Valorization of Organic Residues for the Production of Added Value Chemicals a Contribution to the Bio-based Economy

Accepted ManuscriptTitle: Valorization of organic residues for the production of added value chemicals: A contribution to the bio-based economy Author: Daniel Pleissner Qingsheng Qi Cuijuan Gao Cristina Perez Rivero Colin Webb Carol Sze Ki Lin Joachim Venus PII: DOI: Reference: S1369-703X(15)30131-5 http://dx.doi.org/doi:10.1016/j.bej.2015.12.016 BEJ 6367 To appear in: Biochemical Engineering Journal Received date: Revised date: Accepted date: 30-7-2015 16-12-2015 20-12-2015 Please cite this article as: Daniel Pleissner, Qingsheng Qi, Cuijuan Gao, Cristina Perez Rivero, Colin Webb, Carol Sze Ki Lin, Joachim Venus, Valorization of organic residues for the production of added value chemicals: A contribution to the bio-based economy, Biochemical Engineering Journal http://dx.doi.org/10.1016/j.bej.2015.12.016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. 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Valorization of organic residues for the production of added value chemicals: A contribution to the bio-based economy Daniel Pleissner1, Qingsheng Qi2, Cuijuan Gao2,3,4, Cristina Perez Rivero5, Colin Webb5, Carol Sze Ki Lin4, Joachim Venus1* 1 Department of Bioengineering, Leibniz Institute for Agricultural Engineering Potsdam- Bornim, Potsdam, Germany 2 State Key Laboratory of Microbial Technology, Shandong University, Shanda Nanlu, Jinan 250100, People’s Republic of China 3 School of Life Science, Linyi University, Linyi, 276005, People’s Republic of China 4 School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong 5 Satake Centre for Grain Process Engineering, School of Chemical Engineering and Analytical Science, The University of Manchester, PO Box 88, Manchester M60 1QD, United Kingdom *Corresponding author: Joachim Venus, Department of Bioengineering, Leibniz Institute for Agricultural Engineering Potsdam-Bornim, Potsdam, Germany, Mail: [email protected], Tel: +49 331 5699 112, Fax: +49 331 5699 849 1 Abstract Establishing of a bio-based and green society depends on the availability of inexpensive organic carbon compounds, which can be converted by microbes into various valuable products. Around 3.7 × 109 t of agricultural residues and 1.3 × 109 t of food residues occur annually worldwide. This enormous amount of organic material is basically considered as waste and incinerated, anaerobically digested or composted for the production of heat, power or fertilizers. However, organic residues can be used as nutrient sources in biotechnological processes. For example, organic residues can be hydrolyzed to glucose, amino acids and phosphate by chemical and/or biological methods, which are utilizable as nutrients by many microbes. This approach paves the way towards the establishment of a bio-based economy and an effective organic residues valorization for the formation of bio-based chemicals and materials. In this review, valorization of organic residues in biotechnological processes is presented. The focus is on the production of three industrially important added value chemicals, namely succinic acid, lactic acid and fatty acid-based plasticizer, which have been used for the synthesis of environmentally benign materials and food supplements. Furthermore, utilization strategies of residues coming from fruit and vegetable processing are introduced. Keywords: Succinic acid, Lactic acid, Fatty acids, Bio-plasticizer, Agricultural residues, Food residues, Vegetable residues 2 Introduction Due to the finiteness and environmental impacts of fossil oil, bio-based chemicals have been considered as sustainable alternatives to petroleum-based chemicals in chemical reactions. It is particularly the diversity of biochemical pathways of microbes that allows the biotechnological production of a wide range of industrially relevant bio-based chemicals [1]. The cost-efficient realization of biotechnological processes depends on the presence of inexpensive nutrients, to be used as carbon, nitrogen and phosphate sources for microbes [2]. Pure nutrients (e. g. glucose, amino acids and phosphate), however, are expensive and make most of the developed biotechnological processes economically unfeasible. It was estimated that 3.7 × 109 t of agricultural residues is produced annually as by-products by agricultural industries worldwide [3]. Agricultural residues consist of around 40% cellulose, 30% hemicellulose, 20% lignin, 5% proteins and 5% minerals [4]. In total, it was estimated that 1,376 × 106 t cellulose and 848 × 106 t hemicellulose occur globally every year [3]. Due to the recalcitrant structure of agricultural residues, tough processes, such as hydrothermal treatment or chemical hydrolysis in combination with the use of enzymes are needed for depolymerization and sugar recovery. The released C5- and C6-sugars can then be used as carbon sources in biotechnological processes [5-9]. Furthermore, it was estimated that one third of the food produced globally for human consumption is wasted every year. The overall amount of food wasted corresponds to around 1.3 × 109 t [10, 11]. A composition of 30-60% starch, 5-10% proteins and 10-40% (w/w) lipids constitutes food residues a promising feedstock in biotechnological processes [12-14]. Recovery of nutrients from food residues in the form of carbon, nitrogen and phosphorous compounds can be performed by chemical and biological/enzymatic methods after solubilization of the waste matter [15-19]. Even though the technologies for organic residues valorization are known, the potential of organic residues as nutrient sources in biotechnological process for the establishment of a bio-based economy has not been fully exploited. The concept of circular economy considers the reuse and recycling of any types of waste. In this aspect, the utilization of organic residues in biotechnological process for the production of value added chemicals would enable an application of the circular economy concept on organic waste management and contribute to the development of a bio-based economy. 3 lactic acid and bio-based plasticizer. These chemicals are highly wanted feedstocks in chemical reactions by chemical industry for the synthesis of environmentally benign materials. and polyhydroxyalkanoates. Succinic acid Succinic acid. lignin has been used as substrate for the production of polyhydroxyalkonates and adipic acid [24. waste oil and dairy products [21-23]. enzymes and proteins. there is great demand of succinic acid and lactic acid by food industry as food supplements [26-28]. the cascading use of biomass is particularly important. lactic acid and fatty acid-based plasticizer from food waste is introduced. It should be indicated here that the metabolic versatility of microbes enables the fermentative production of a wide range of products. The aim of this review is to give an introduction to biotechnological utilization strategies of organic residues. valorization strategies of residues from fruit and vegetable processing are presented. microorganisms are able to synthesize long carbon chains in form of fatty acids. meat and derivatives. carboxylic and dicarboxylic acids. It should be admitted that the metabolic versatility of microbes opens not only the door to the development of biotechnological processes for the production of value-added chemicals. but also to innovative treatment strategies of organic residues. including biochemical principles and strain development. such as phytosterols. flavonoids. glycerol and erucic acid from fruits and vegetables. animal waste. 25]. The options range from the production of antioxidants. such as lactic acid and succinic acid. The simultaneous production of materials and food supplements from organic residues contributes to the principle of cascading use of biomass. Furthermore. namely succinic acid. Similarly. acrylic acid and esters [23]. a member of the C4-dicarboxylic acid family. is an important platform chemical and was identified as one of the top twelve potential chemical building blocks for 4 . The products range from amino acids. fatty acid methyl esters. such as aspartate and lysine. Furthermore.Within the circular economy. Lignocellulosic biomass has also been used for the production of various compounds. polypropylene. Furthermore. An integrated bioprocess for the simultaneous production of succinic acid. The current options for the valorization of waste organic residues are shown in Table 1. for the production of three added value chemicals. Figure 1 shows relevant industrial metabolites obtainable via fermentative processes [1]. as it considers the production of food and feed prior to material and energetic usage [20]. Mannheimia succiniciproducens and Bacteroides fragilis [36-39]. Most of the succinic acid producing strains were isolated from rumen. In order to overcome this drawback. are anaerobic or facultative anaerobic and capnophilic.8 g SA g-1 glucose. In order to create economically feasible bio-based succinic acid production processes. Three different biochemical strategies for succinic acid production: the reductive TCA pathway. rational strain development by metabolic engineering is crucial. such as Escherichia coli and yeasts.the future by the US Department of Energy [29]. Recent estimates of the market potential of succinic acid and its immediate derivatives were projected to be as much as 245. In the past decade. bread wastes and other types of food waste) achieved similar results to those obtained from conventional media. many of them are even conditional pathogenic bacteria and grow slowly. It can be used to produce various high value commodity derivatives for industrial applications. the pretreatment of food waste can be carried out by in-situ enzymatic hydrolysis. Furthermore. an exciting movement towards bio-based chemicals has been prompted from fossil feedstock to renewable raw materials due to the declining reserves of fossil feedstock and the environmental impacts of oil-based industries [34. there is a demand for a faster and cheaper development of new production strains. 33]. with a productivity over 1 g L-1 h-1 and a yield of 0.000 t per year. such as pharmaceutical. 31]. the oxidative TCA pathway and the glyoxylate shunt exist (Figure 2). Table 2 presents a summary of fermentative succinic acid production from conventional media and organic residues using genetically modified and wild type strains. manufactured at industrial scale mainly by catalytic hydrogenation of petrochemically derived maleic acid or maleic anhydride [32. surfactants and detergents [30. Anaerobiospirillum succiniciproducens. The maximum theoretical yield of 1. food. As shown in Table 2. which is a relatively simple approach compared to the traditional chemical pretreatments required to make carbon compounds available from lignocellulosic materials. which has been found to be produced naturally by a number of microbes including Actinobacillus succinogenes. natural succinic acid producers usually lack of genetic tools. Some of the renewable feedstocks tested (e. However.7 mole succinic acid per mole glucose can be obtained from 5 . Consequently. which preferably can utilize renewable resources [1]. researchers focused on genetically modified non-natural producers. antibiotics. 35]. which make them inappropriate for industrial succinic acid production [40].g. Succinic acid is an intermediate of the tricarboxylic acid (TCA) cycle and a fermentation endproduct. which can operate at low pH. However.11 mole mole-1 glucose in shake flask cultures [40]. Therefore. this acid tolerant Saccharomyces cerevisiae strain produced 3. combined with gene deletion of pdc1. a continuously stirred tank 6 . This approach prevents bacterial contamination and reduces the amount of additives needed for pH regulation and consequently benefits to downstream processing [40]. On the other hand. To date. pdc6. coli FumCp. By employing this strategy.3 g L-1 succinic acid after 40 hours of cultivation. Continuous production of succinic acid is likely to outperform batch processing.62 g L-1 succinic acid at a yield of 0. This is neither practical nor efficient in large-scale fermentation processes and leads to increased operating costs. coli that makes all these three pathways work under aerobic. In order to keep microbes active. glucose [42].8 in a bioreactor. modulating the redistribution of metabolic flux and increasing the transport rate of the sole carbon source. Recently.2 mole mole-1 glucose at pH 3. the reductive pathway was constructed in S. cerevisiae by overexpression of pyruvate carboxylase PYC2p. The latter two strategies can provide more energy. eliminating the NADH competitive pathways. the pH of media needs to be controlled by adding a base. only 1 mole succinic acid per mole glucose can be obtained from the oxidative TCA pathway and the glyoxylate shunt [41].the reductive TCA pathway. succinate salts are formed and subsequent separation of salt ions needs to be carried out after fermentation in order to produce pure succinic acid. gpd1and fum1 [43]. The major drawback of using microbes in succinic acid production is the decrease in pH of fermentation media as a result of succinic acid formation. Furthermore. which is vital for cell growth and maintenance. However. Reactor design and operation of succinic acid fermentation are likely to become more important with the prospect of bulk scale production on the horizon. cytosolic retargeted MDH3p. further strain development is needed in order to increase productivity. The engineered strain produced 13 g L-1 succinate at a yield of 0. especially when considering the projections of future processing quantities. the number of studies on continuous succinic acid producing cultures is limited. yeasts have been explored recently for succinic acid production. As a consequence. FRDS1p and E. By redirecting the carbon flux towards the glyoxylate cycle. microaerobic and anaerobic conditions by depressing the inhibition of low dissolved oxygen. coli strain YL106/pSCsfcA was able to produce 85. pdc5. Li et al. designed and developed a novel whole-phase succinic acid fermentation strategy in engineered E. the engineered E. cell recycling systems using membranes were used in an attempt to enhance productivity [45]. (ii) good mass transfer performance. institutions. The advantages of using cotton as immobilization material are: (i) chemically inert and not harmful to cells. which enables the formation of an external recycle biofilm. (v) simple operation and suitable for mass production. (iii) higher cell recovery. cotton was used as the packing bed for cell immobilization for continuous succinic acid and butanol fermentations. which create complex organic waste streams. as immobilization materials in a FBB. We aim to obtain a similar or even better FBB operation stability and cell viability during continuous succinic acid fermentation as compared to the performance in the typical materials. However. Examples of typical sources of wasted food are households. where a special polypropylene composite support was used to enhance cell immobilization. Solid-state fermentation was performed to produce enzyme mixtures of α-amylase and protease for the hydrolysis of bread waste instead of using commercial available enzymes. corn bran and wheat straw. succinogenes. Urbance et al. which means that the steady-state succinic acid production is difficult unless the residence time is very long. 47]. such as wound cotton towel. respectively.8 g L-1 h-1) by A. Food waste can be defined as a by-product or residues of food processing by industries and consumers. Recent research conducted by our group focused on evaluation of the feasibility for using agricultural residues. [44] reported high productivities (up to 8. the results are scattered with low succinic acid yields at high productivities. which resulted in over 100 g L-1 glucose and 490 mg 7 . (vi) high mechanical strength and long service time. which has not been recycled or used for other purposes. [46. grocery and bakery stores. schools. According to Yan et al. Spirally wound cotton towel has a porosity over 95%. such as cotton stover. [48].reactor has the disadvantage of cells washout. restaurants. the bacterial cells attached onto the fibrous matrix are continuously replenished. 47] and Li et al. Fibrous bed bioreactor (FBB) with cell immobilization has been reported with the advantages of achieving high cell density and long term stability in continuous succinic acid fermentation with high productivity [46. During continuous fermentation. More recently. (iv) low cost. which results in constant cell viability and biomass in a FBB. Our group previously demonstrated that succinic acid can be produced using waste bread as the sole nutrient source [49]. research has appeared switching to the use of food and agricultural wastes as feedstock for fermentative succinic acid production. Apart from normal suspended cell systems. and for the production of organic acids. By adding yeast extract as nitrogen source and MgCO3 for pH control. Stringent waste regulations worldwide are pushing local companies and sectors towards higher sustainability standards. such as citric and αketoglutaric acids. which can all be found in food waste. The created strain named Y-3314 produced 45 g L-1 succinic acid in shake flasks containing CaCO3 as buffer and 126 g L-1 8 . lipolytica was presented and based on the deletion of gene encoding subunit of the succinate dehydrogenase [55].12 g L-1 h-1. Yu et al. succinogenes. The development of novel strategies for food waste utilization is economically and environmentally sound. This corresponds to an overall yield of 0. lipids and alkanes and simple carbon sources. Using a recombinant strain of Y.37 g per g of biomass [51]. After pretreatment of the lignocellulosic biomass with 1-allyl-3-methylimidazolium chloride ionic liquid (AmimCl) and enzymatic hydrolysis. succinogenes 130Z and E. Y. Recently. This hydrolysate derived from waste bread was used in A. which led to the production of 47. lignocellulosic biomass derived from corn stover and pinewood was adopted for succinate production using A. which is the highest succinic acid yield compared to other food waste-derived media. For instance. lipolytica a promising candidate for the degradation and valorization of food waste. Y.3 g L-1 succinic acid with a yield of 1. with an average yield of 0. at the same time it represents an inexpensive nutrient source for biotechnological processes and contributes to the bio-based economy [52].7 g L-1. such as glucose and glycerol. [50] examined the feasibility of using corncob as feedstock in succinic acid fermentation by A.16 g succinic acid per g glucose and productivity of 1. succinic acid production reached 20. a total of 23. Food waste utilization contributes to a solution of the waste issue. coli MG1655. This broad range of substrate makes Y.58 g g-1 sugar without any detoxification of corncob hydrolysate. and avoids the formation of inhibitory compounds such as aldehydes.6 g L-1 of succinic acid was produced with a yield of 0.55 g succinic acid per g bread. lipolytica. Meanwhile. lipolytica was shown to be able to produce succinic acid [53].L-1 free amino nitrogen (FAN). lipolytica can utilize hydrophobic substrates such as fatty acids. succinogenes fermentations.15 g L−1 h−1 under oxygen limitation were obtained [54]. 25 g L−1 succinic acid and a volumetric productivity of 0. Another approach in order to produce succinic acid using Y. a pretreatment step is required which converts the cellulose and hemicellulose fractions into C5 and C6 sugars. In order to produce utilizable carbon sources from lignocellulosic biomass. lactic acid is not only an industrially relevant platform chemical. However. Lactic acid is produced biotechnologically using several microbes. green solvent and cleaning agent [58]. in order to develop innovative food waste utilization strategies. our current research supported by the General Research Fund from the Hong Kong Research Grants Council.5-0.glycerol as carbon source. lactic acid gained significant attention as a monomer to be used in the production of the biodegradable plastic. Furthermore. Therefore.000 t. but also pentoses into lactic acid [9. 6577]. which are able to efficiently convert hexoses. pharmaceutical and chemical industries have been using lactic acid in many applications. such as Rhizopus oryzae are used as production strains. 59. antimicrobial agent. further strain development is needed in order to increase volumetric productivity and yield. Only few studies have been reported for fermentative succinic acid production from wastes [56. such as pH regulation. Food waste is an advantageous substrate for lactic acid production as the supply of additional nutrients. lipolytica has promising potential for succinic acid production. Yields obtained using lignocellulosic materials vary from 0. in order to stimulate cell 9 . such as carbon and nitrogen compounds. In 2013. Bacillus. the demand of lactic acid was estimated at 714. yeast. which is mainly based on the demand of bio-plastic [61-63]. including bacteria. 60]. Lactic acid Lactic acid (2-hydroxypropionic acid) is one of the most promising platform chemicals. cyanobacteria and algae [61]. which can be produced biotechnologically. Streptococcus. The fermentative lactic acid production has a long history and was first carried out at industrial scale in 1881 [64]. A comparison of lactic acid production from conventional media and low-cost feedstocks is shown in Table 3. It is expected that the demand further increases at an annual rate of 15. Pediococcus and Enterococcus. bacteria belonging to the groups of Lactobacillus. 57]. cosmetic. The outcomes indicate that the application of genetically modified Y. lipolytica strain to degrade mixed restaurant food waste and to produce succinic acid and polyhydroxyalkanoates simultaneously at high productivities and yields.5% between 2014 and 2020. which has the potential to substitute considerable amounts of petroleumbased plastics in the future [26. Lactococcus. The food. but also an important product for the bio-based economy. fungi. and filamentous fungi. Nowadays. Thus. poly(lactic acid). focuses on the construction of an engineered Y.9 g g-1. paracasei converted 90% of the supplied glucose into lactic acid and more than 100 g L-1 lactic acid was produced in a batch culture within 30 hours. The simplicity of the biochemical pathway from glucose to lactic acid additionally favors high yields (Figure 2). Under these conditions. 79]. The lactic acid concentration during continuous cultivation was constant at around 50 to 60 g L-1. 81-83]. yeast extract) compounds.9 g lactic acid per g glucose can be obtained in practice [73. However.05 h-1 at the beginning to 0. Cell retention was carried out with hollow fibre membranes. the possibility of fermentative lactic acid production using barley hydrolysates.0.growth and metabolic activity is unnecessary. This approach revealed the opportunity to design 10 .35 h-1 after 110 hours. Batch and continuous cultivations were carried out at 40. the costs of carbon (e. the yield of lactic acid is generally high and up to 0. The retention and recycling of cells continuously increased the biomass concentration in the fermenter. biomass formation is restricted and most of the carbon consumed is used in lactic acid formation. g. despite high yields. The process was thereafter performed as a continuous culture with cell retention for more than 120 hours (Figure 3). The increase in biomass concentration eventually caused an increase in volumetric productivity. 80]. Recently. such as starchy and lignocellulosic materials from agricultural industry. Several organic residues were successfully investigated as nutrient sources. the recent research focus is on making organic residues available as inexpensive nutrient sources. L. Thus. with the goal to develop costefficient fermentation processes. Therefore. Both values were found to be appropriate in order to achieve high volumetric lactic acid productivities and yields.5 °C and pH 6. Basically. which rose to 25 g lactic acid per litre per hour. This productivity was up to four times higher than the productivity found in comparable continuous cultures without cell recycling. It should be admitted here. two moles of lactic acid can be produced from 1 mole of glucose. nitrogen-rich grass press juice and food waste [78. to be used as nutrient sources in fermentations. are high and challenge the economic feasibility of the industrial production of the rather inexpensive product lactic acid [79. glucose) and nitrogen (e. the dilution rate was continuously increased from 0. that the yields of lactic acid in these studies were similar to the yields obtained when defined media were used in fermentations. Lactic acid fermentation is carried under anaerobic or microaerobic conditions. g. 78. green press juice from alfalfa and salts in batch cultures and continuous cultivation with biomass retention of Lactobacillus paracasei was investigated [84]. Due to the increase in volumetric productivity. plasticizers from biological sources are biodegradable and do not accumulate in the environment. sunflower and rubber seed [88. Some microalgae are even able to accumulate more than 50% of their biomass as lipids [92].000 t annually [85. Oleaginous microalgae are able to accumulate more than 20% of their biomass as lipids. Compared to petroleum-based plasticizer. 86]. 91]. linseed. 11 . under stress conditions. but not by mammals. vertical arrows). The formation is based on simple and conventional reactions. containing saturated and unsaturated fatty acids. such as polyvinyl chloride [85]. are not present in all biological materials [87]. canola. The biosynthesis of unsaturated and polyunsaturated fatty acids basically includes two reactions: elongation and desaturation.effective and efficient lactic acid fermentation processes based on organic residues as nutrient sources [84]. Therefore. bio-plasticizer and biodiesel. microalgae are known as a source of fatty acid containing lipids. the carbon chain is extended by two carbon atoms supplied by malonyl-CoA (Figure 5. In addition to vegetable oils. Synthesis of polyunsaturated fatty acids starts with the introduction of a second double bond in the carbon chain of a monounsaturated fatty acid like palmitoleic or oleic acid. 78. Bio-plasticizer Bio-plasticizers are used to improve the flexibility and stability of polymers. The introduction of further double bonds between the first existing double bond and the terminal methyl group is essential for the synthesis of polyunsaturated fatty acids. which. horizontal arrows). 89]. due to differences in biochemical pathways. This particular reaction is carried out by plants. bio-plasticizers are considered as environmentally benign compounds and are produced at around 200. such as soybean. such as nitrogen limitation [13. much efforts have been put on the investigation of vegetable oils from various sources. the precursors of all n-3 and n-6 polyunsaturated fatty acids (Figure 4). The advantage of this approach is the simultaneous formation of two wanted products from fatty acids. The bottle neck of bio-plasticizer production is the availability of unsaturated fatty acids. including methylation of fatty acids and epoxidation of unsaturated fatty acid methyl ester using hydrogen peroxide in presence of toluene and formic acid (Figure 4). 90. microalgae and yeasts. In order to make unsaturated fatty acids for the production of bio-plasticizer available. During elongation. Desaturation. includes the formation of double bonds by dehydrogenation of carbon atoms catalyzed by desaturases (Figure 5. even when microalgae can be cultivated in bioreactors. the realization at larger scale is challenging. 78. respectively [13]. [96] supplemented spent yeast lysate with glycerol in order to increase the C/N ratio from 20 to 35.2 and 0. Table 4 lists different microalgal and yeast strains that have been investigated for the production of fatty acids.However. however. Using the alga Schizochytrium mangrovei and food waste hydrolysate. With this 12 . respectively [95]. For instance. The tested microalgae and yeasts grew well on organic residues derived nutrients and all microbes accumulated lipids including unsaturated fatty acids. pyrenoidosa was inhibited when more than 30 g L-1 glucose was supplied.2 g L-1 d-1) productivities of C.9 g L-1 d-1 was obtained. g. Ryu et al. their abilities to utilize organic residue derived nutrients and the mode of cultivation. The accumulation of lipids and unsaturated fatty acids depends on the carbon-to-nitrogen (C/N) ratio. an adjustment is difficult when complex organic substrates are used. Therefore. The volumetric lipid and unsaturated fatty acid productivities were dependent on the type of strains. glucose) makes cultivations at larger scale economically unfeasible. fatty acids. in oleaginous microbes [13. Therefore. the growth of C. Fed-batch processes are particularly an attractive option when the microbes are sensitive to high substrate concentrations. the cultivation is restricted by fairly low biomass productivities and high demand of nutrients [93]. It is well known that the limitation in nitrogen favors the accumulation of both. For example.8 g L-1 d-1) and fatty acid (1. pyrenoidosa were found (Table 4) as compared to batch cultures in presence of food waste hydrolysate [78]. Phototrophic algal strains have the advantage of converting carbon dioxide into biomass and thus. lipids and fatty acids. Nevertheless. Thus. fed-batch cultures performed at a glucose concentration below 30 g L-1 is an appropriate fermentation strategy. Due to a higher biomass concentration in fed-batch cultures. considerably higher volumetric lipid (1. the volumetric lipid and fatty acid productivities were 2. recent research has been focused on the use of organic residues as nutrient sources [94]. The biomass productivity of heterotrophic algal strains is high. the need of expensive nutrients (e. Cultivations of the listed microbes were carried out in presence of hydrolyzed organic residues as carbon and/or nitrogen sources. Chlorella vulgaris was cultivated under mixotrophic conditions on soy whey and thin stillage. and an unsaturated fatty acid productivity of 0. and in particular unsaturated fatty acids. 90.9 g L-1 d-1. However. 91]. in order to develop feasible cultivation processes.1 and 0. Decreased lipid contents of 50% and 61% were obtained when the C/N ratios in the feed were 65 and 80. In this way. with nitrogen-rich streams. and also biofuels and chemicals can be produced when using those wastes as culture media in fermentations [100]. prebiotic oligosaccharides and natural antioxidants. the wine and olive oil industries leave behind a large amount of wastes throughout the production chain. They found highest lipid content of biomass (75%) when only glucose was supplied during fed-batch phase. the volumetric lipid productivity of the yeast Crytococcus curvatus was doubled (Table 4). [97] carried out fed-batch cultures of Rhodosporidium toruloides with different C/N ratios in the feed. not all substrate was consumed. such as reinforcement materials in polypropylene composites [101] or novel pectin materials with good surfactant and biological properties [102]. However. After citrus juice extraction. and thus improve the profitability of the process [103]. cosmetic or food industry in form of additives. enzymes or ingredients are extracted (Table 5).approach. research is focusing in obtaining innovative products from those wastes. which could be drawn upon for a more sustainable performance of the plant: from tree cultivation to wastewater streams or solid residues generated after filtration [98. succinic acid. microbial consortia or solid state fermentation are some of the most employed techniques [105]. Wiebe et al. In order to obtain an appropriate C/N ratio for increased productivities of fatty acids. 13 . Valorization of residues from fruit and vegetable processing Residues coming from fruit and vegetable processing industry have attracted much attention in recent years as they represent up to 60% of its total production. 50% of the fresh fruit becomes citrus wastes. More recently. such as lignocellulosic hydrolysates. to be used as feeding material in fermentative processes. Citrus wastes can be utilized for producing enzymes (especially pectinase) citric acid. 99]. these are organic solids with high content in sugars but low amount of protein. one might consider mixing carbon-rich hydrolysates. For the valorization of other agricultural residues. dietary fibers production. Valuable phytochemical compounds for the pharmaceutical. The fact that lipid accumulation as a secondary product is triggered when cultivation is carried out under conditions of restricted growth particularly favors the application of fed-batch over batch processes. respectively. Similarly. such as green press juice and food waste hydrolysate. mixed substrates. potato residues combined with potato starch have been directly fermented into lactic acid in septic systems [104]. which can be 14 . in which oil extracted from spent grounds serves as polyhydroxyalkanoate (PHA) precursor and the remaining solids after extraction are hydrolyzed in order to generate new feedstocks for either further PHA or carotenoids production by different microorganisms. 1. 270 kg glucose. 4. the most extended form of organic residues valorization is in the form of bioenergy. Extraction of lipids from algal biomass and remaining solids gives 111. 478. 107]. glycerol. Obruca et al. ß-carotene.7 kg FAN and 1.917. Furthermore.000 kg mixed restaurant food waste. Alternatively. nutrients recovered from food waste can be used for the fermentative production of succinic acid. Integrated biorefinery concept for the production of succinic acid.673 kg lactic acid.000 kg food waste would result in the production of 251.1 kg succinic acid [56]. For the process shown in Figure 6. an external carbon source is required as the residues do not contain sufficient carbon compounds. which produce 78 kg bio-plasticizer [113].3 kg algal biomass. biodiesel. opportunities were introduced to valorize organic residues for the production of added value chemicals. the nitrogen-rich residues obtained after lipid extraction from algal biomass and remaining solids are sufficient for the production of 1. lactic acid and bioplasticizer Integrated biorefinery concepts have been presented for the simultaneous production of various products. Applying all nutrients recovered from 1.9 kg phosphate can be recovered.5 kg lipid-rich solids remain. The by-products of a biorefinery facility are also subject of valorization to achieve a real integrated facility as promoted by the cascade approach [1]. 113].Although it is not discussed in this review. [108] presented another scenario of integrated valorization of organic residues in the coffee industry. Furthermore. The concept for the production of lactic acid and bioplasticizer was tested in our earlier studies [78. lactic acid and bio-plasticizer (Figure 6). such as ethanol and succinic acid from industrial hemp [109].5 kg glucose is required. In the previous sections. lactic acid and poly-3-(hydroxybutyrate-co-hydroxyvalerate) have been produced from stillage [106.4 kg unsaturated fatty acids. 111] and polyhydroxybutyrate and bioenergy from banana residues [112]. In this context. Based on the facts provided above an integrated biorefinery concept was developed for the simultaneous production of succinic acid. From 1. Similarly. However. fermentative production of succinic acid using hydrolysate derived from mixed food waste was demonstrated by our groups [56]. omega-3 fatty acids. bioethanol and bioenergy from algal biomass [110. Nutrients recovered from food waste are sufficient to produce 213. glycerol. the successful and efficient conversion of organic residues into succinic acid likely depends on the use of engineered microbial strains. lipolytica is currently being developed in our laboratory as a cell factory for biological production of succinic acid by metabolic pathway engineering.40 g L-1 h-1 and 0. The metabolic versatility of microbes enables the fermentative production of a wide range of products. Using fed-batch fermentation strategy. it is of particular interest to develop processes that can be operated in a decentralized modus and contribute to the regional utilization of organic residues. This approach does not only contribute to the reduction of the amount of organic waste that needs to be treated. corn bran and wheat straw are currently tested as cell immobilization materials in FBB. whole cell bioconversion and upgrading of industrial wastes. This aspect particularly contributes to the principle of cascading use of biomass. In this aspect. and lowering of bulk viscosity. Conclusions and future perspectives Recovered nutrients from organic residues in the form of sugars and amino acids.40 g g-1 glycerol (unpublished result).2 g L-1. This oleaginous yeast has been demonstrated as a promising host for succinic acid production using crude glycerol as carbon source. productivity and yield resulted were 160. More research is needed in order to realize and implement innovative and effective waste valorization strategies. but also to the production of environmentally benign and added value chemicals with great industrial potential. Furthermore. lactic acid and bio-based plasticizer are potential precursors in chemical reactions. Succinic acid. Various agricultural residues such as cotton stover. recent research conducted in our group focuses on the use of FBB technology and hydrolysate of agricultural residues or food waste as feedstock. As mentioned previously. as well as the obvious potential benefits of increased cell concentration. Valorization of organic residues opens the door to the development of innovative waste treatment strategies and biotechnological processes. 115]. While lactic acid and fatty acid productions are possible with native microbial strains. Such immobilization offers several potential advantages of a process engineering nature to the continuous fermentation system. the final succinic acid concentration. These include ease of handling and of cell separation. but also phosphate can be used as feed for many microbes in biotechnological processes. 15 .supplied in form of hydrolysate from cellulose and hemicellulose-rich agricultural residues [114. succinic acid and lactic acid can be used as food supplements. A strictly aerobic yeast Y. 0. which contribute to the bio-based economy. K. Qi. China [Project No. The Authors want to acknowledge the contribution of the COST Action TD1203 – EUBis. Therefore. CityU189713] and the State Key Lab of Microbial Technology in Shandong University. nutrients recovery from food supply chain waste such as expired food and beverage waste from grocery store would be an innovative waste-based biorefinery strategy. Lin on metabolic engineering of Yarrowia lipolytica for the simultaneous production of succinic acid (SA) and polyhydroxyalkanoates (PHAs) is part of the research projects supported by grants from the Research Grants Council of the Hong Kong Special Administrative Region. materials and fuels would be the future trend for waste valorization. carbohydrates. Lin gratefully acknowledge the Innovation and Technology Funding from the Innovation and Technology Commission [ITS/353/12] in Hong Kong for their support in research project ‘Sustainable Biorefinery Concept Based on Microalgal Biomass Produced from Mixed Food Waste‘.g. the development of bioconversion process to convert the nutrients in expired food and beverage wastes (e.K.S. C. lipid. 16 .Furthermore. China [M2014-03]. Acknowledgements The work presented by Q. Pleissner and C. minor constituents with high market values) for the production of chemicals. Gao and C. proteins.S. D. I. Kwan. Zhao. Sayeki. Valorization of industrial waste and by-product streams via fermentation for the production of chemicals and biopolymers. U. [9] K. Cederberg. J. 2013. Jiang. American Chemical Society 2014. S. A. Vlysidis. Shupe. C. Bentsen. [2] Q. Sonesson. Bioresour Technol. J. C. Zhang. [11] J. [10] J. Dao. Pleissner. [3] N.J. Q. Gu. Kopsahelis. T. Simultaneous saccharification and high titer lactic acid fermentation of corn stover using a newly isolated lactic acid bacterium Pediococcus acidilactici DQ2. K. Miyoshi. in: S. 247-263. pp. Agricultural residue production and potentials for energy and materials services. A. Qi. C. [5] B. Mochizuki. pp.H. van Otterdijk. Lopez Garcia. C. 38. Obare. Koutinas. From a co-production design to an integrated single-cell biorefinery. A. Gustavsson. 70.A. M. Springer Berlin Heidelberg2007. [12] M. J. Hse. Pleissner.C. T. [6] R.) White Biotechnology. T.H. The methodology of the FOA study: global food losses and food waste – extent. [8] J. Crit Rev Biotechnol. [7] Y. Lin.References [1] A. Matsumoto. T. Felby. Cederberg. Nishiyama. Bao. Liang. pp. [4] D. Luque (Eds. Kamm. Anim Sci J. Sell (Eds. H. 32 (2014) 1328-1335.F. Hydrolysis of lignocellulosic materials for ethanol production: a review. Chu. Global food losses and food waste – extent. Kitagawa. 40 (2014) 59-73. 83 (2002) 1-11. Singh. A. Kookos. J. Prog Energy Combust Sci. Q.S. 13 (1993) 151-172. 14 (2012) 2821-2830. causes and prevention. Thorsen. R. 175-204. C. D. Renewable chemical feedstocks from integrated liquefaction processing of lignocellulosic materials using microwave energy. 17 . Meybeck. R. A. Ulber.O. Venus. The Swedish Institute for Food and Biotechnology. Sun. Agricultural residues as feedstocks for lactic acid fermentation. Bioresour Technol. I. Biotechnol Adv. causes and prevention. Biorefineries – Multi Product Processes. Xu.K. A. 72 (2001) 34-40. Sonesson. D. 2011. U.S. 43 (2014) 2587-2627. D. Green Chem. M.) Green Technologies for the Environment. J. Kamm. Abe. 135 (2013) 481-489. Papanikolaou.K. Cheng. M. A. in: R. Chemical composition and energy value of dried meal from food waste as feedstuff in swine and cattle. N. Qiao. pp. Food and Agriculture Organization of the United Nations. Gustavsson. B. Chem Soc Rev. Takasu. Lignocellulose Biotechnology: Current and Future Prospects. Emanuelsson. Kuhad. Keegan. C. M. [17] J. C. Johnson. Lignin valorization through integrated biological funneling and chemical catalysis. G. M. Energy Environ Sci. L. S.M. Beckham. Utilization of byproducts and waste materials from meat. [24] J. G.G.T. Lin. Shriner.R.A. Salm. Vardon.J. Lin. [14] A. technologies and the conflict with food production.A. Jayathilakan. Pleissner. Linger. Kim.K. Feasibility of producing ethanol from food waste. Panoutsou. Z.W. Yao. 111 (2014) 12013-12018. Lam. Pak. M. Fed batch enzymatic saccharification of food waste improves the sugar concentration in the hydrolysates and eventually the ethanol fermentation by Saccharomyces cerevisiae H058. Lau. Ind Eng Chem. [18] W. Lin. Beckham.T. Pienkos.C. M. Mirabella. Pleissner. Johnson.Y. 137 (2013) 139-146.J. Zhi. Castellani. D.H. X. Li. D.E. S. Haider. Sala. Food waste as nutrient source in heterotrophic microalgae cultivation. [23] S. K. J Clean Prod. Franden. butanol and ethanol production from domestic organic waste by solventogenic clostridia. Claassen. 15 (2013) 690-695. G.C. W. J.S.A. [25] D. 31 (2011) 2121-2125. Guarnieri. Radhakrishna. [21] K. Waste Manage.-z. J Food Sci Technol. A. M. Hunsinger. Biomolecules. Current options for the valorization of food manufacturing waste: A review. V. Guarnieri. 18 . Karp. Green Chem. Hydrolysis of starch by sulfurous acid.C. Franden. C.M. J. G. J. T.[13] D. K.K. C. Bioresour Technol. C. Braz Arch Biol Technol. 55 (2000) 183192. 51 (2015) 506-520. Zhang. [19] S. Yao. Yan.L. Sun.W. 3 (2013) 651-661.K. Sultana. 65 (2014) 28-41.C.Y. Strathmann. Sun.T. 33 (1944) 1001-1003. K.B. Valorisation of bakery waste for succinic acid production. Production of fungal glucoamylase for glucose production from food waste.M. M.S. [16] M. Gorman. [20] D. Bardhan. Z.S. M. C.R. 7 (2013) 193-206. P Natl Acad Sci USA. Budde. Z. Gupta.T. M.G. J. Elbersen. [22] N.A. Strathmann. J Mol Microbiol Biotechnol. M.A.. Lee. P. [15] P. W. D.K. Acetone. Bawa.J.J. 49 (2012) 278-293. Wu. Biorenewable chemicals: Feedstocks.T. C. Karp. R. A.S. Biofuel Bioprod Bioref. T. E. B. B. Vardon. Kretschmer. Leung. Lam. Renew Sust Energ Rev. E. Cascading use: a systematic approach to biomass beyond the energy sector. C. Chupka. Hayek. 8 (2015) 617-628. 2 (2000) 39-44. poultry and fish processing industries: A review. López-Contreras. Han. Linger. Adipic acid production from lignin. Isolation and characterization of a new succinic acid-producing bacterium. nov. Beppu. Applied Microbiology and Biotechnology. Succinic acid production by Anaerobiospirillum succiniciproducens ATCC 29305 growing on galactose. Soetaert. M. M. Cok. Prior. Vieira. Trends Food Sci Tech. J. 8 (2014) 16-29. from bovine 19 .[26] F.A. Biotechnology of succinic acid production and markets for derived industrial products. [29] T. Salgado. S.S.H. Lee. Jain. Biotechnol Adv. J. Hong. Wang. Jain. [35] X. Zeikus. Wang.C. Yan. 18 (2008) 1792-1796. Wan. P. Bioresour Technol. D. [33] J. K. C. M. 12 (2010) 539–554. B. G. Petersen.M. Chang.Y. development and industrialization. Zhang. Int J Syst Bacteriol. A. Chen. Mannheimia succiniciproducens MBEL55E. [34] C. H. B. L. Bozell. 47 (2011) 254-263. Lee.R. Balciunas.the US Department of Energy’s “Top 10” revisited. Petersen. 156 (2014) 6-13. G.M.P.J. H.K.K. A.M. Werpy. Natural-based plasticizers and biopolymer films: A review.A. [37] P. Lee. Metabolic engineering of Escherichia coli: a sustainable industrial platform for bio-based chemical production. R. Yang.A. 5 (2010) 1149-1163. Actinobacillus succinogenes sp. Rumler. dos Santos. (2004). Biotechnol J. [27] B. M. Z.H. I. applications and production: A review. Patel. Y. S.V. S. Technology development for the production of biobased products from biorefinery carbohydrates . De Mey. Zhang. Xu. Kumar. [38] P. Y. Liu.G. Washington DC. [30] J. J.A. Guo. galactose/glucose. 45 (2010) 1103-1114. Ming. Oliveira. Lee.Y.N.K. and galactose/lactose. Y. 31 (2013) 1200-1223. Roes.J. D. Top value added chemicals from biomass. J Microbiol Biotechnol. M.M.N. Tian. W. da Silva. L. Chang. Singh. Lactic acid properties. Elankovan. Biofuel Bioprod Bioref.. [31] J.d. Tsiropoulos. Eur Poly J. a novel succinic-acid-producing strain from the bovine rumen. Guo. Zhou. [36] M. Guettler. USDOE. 51 (1999) 545-552. [28] M. Beauprez. [32] J. Castillo Martinez. W. 49 Pt 1 (1999) 207-216.C. Green Chem. Process Biochem. M. B. S. E. Poly(butylene succinate) and its copolymers: Research. Domínguez González. Xing. 30 (2013) 70-83. Succinic acid production derived from carbohydrates: An energy and greenhouse gas assessment of a platform chemical toward a bio-based economy. M. Microbial succinic acid production: Natural versus metabolic engineered producers. A. Novel membrane-based biotechnological alternative process for succinic acid production and chemical synthesis of bio-based poly (butylene succinate).L. Converti.O. Y.rumen. R. Pometto. Xing. Metab Eng. Z.F. C.A.Y. S. S.C. 89 (2014) 1760-1766. 24 (2014) 87-96.K. H. C.-Z. Dong. DiSpirito. Zheng. Liu. Biochem Eng J. Evaluation of succinic acid continuous and repeat-batch biofilm fermentation by Actinobacillus succinogenes using plastic composite support bioreactors. Denli. 65 (2012) 10-15. 91 (2014) 92-98. Ai.L. Q. 37 (2010) 1033-1040. Tao. H. Zhou. III. Leung. J Chem Technol Biotechnol. Utilisation of waste bread for fermentative succinic acid production. A. Bioresour Technol. Li. 58 (2002) 663-668. Bioresour Technol.Y. S. Substrate and product inhibition kinetics in succinic acid production by Actinobacillus succinogenes. Yu. A fibrous bed bioreactor to improve the productivity of succinic acid by Actinobacillus succinogenes. D. Bioresour Technol. 41 (2008) 128-135. Zheng. Appl Microbiol Biotechnol. Ye.S. Lang. Biochem Eng J. X. Urbance. Yang. [43] D. J. [47] Q. Zhang. Xu. Yan. Qi. P. [39] S. Zhang. S. P.-Q. Yang. M. [46] Q. Z. [50] J. Appl Microbiol Biotechnol. A. Y. Cheung.E.-T. Lin. A novel whole-phase succinate fermentation strategy with high volumetric productivity in engineered Escherichia coli. [49] C. Q. Zhang. [48] L. J. Zhu. P. Z.K. Construction of reductive pathway in Saccharomyces cerevisiae for effective succinic acid fermentation at low pH value.H. Yan. K. Tan. Enhanced butanol production by coculture of Clostridium beijerinckii and Clostridium tyrobutyricum. Li.C. J. [44] S. Li. Fermentation process for continuous production of succinic acid in a fibrous bed bioreactor. A. C. 156 (2014) 232-239.D. X. 20 .M.J. Yang. Liang. Zhang. Metabolic engineering of Saccharomyces cerevisiae for the biotechnological production of succinic acid.S. C. J. Wu. [40] A. C. J. A. Wang. Nicol.T. Gebhardt. Du. N. S. [45] C. J Ind Microbiol Biotechnol. Sun. Development of succinic acid production from corncob hydrolysate by Actinobacillus succinogenes. Webb. Metab Eng.J. Liang. Z. Wang. G. 65 (2004) 664-670. J. W. Koutinas. Wang. Lam. Q. Dong.-F. Continuous succinic acid fermentation by Actinobacillus succinogenes. [42] Y. 143 (2013) 397-404. Biochem Eng J 73 (2013) 5-11. Biochem Eng J. J. Yang. Bolotina. 149 (2013) 333-340. M. Raab. Chen. [41] X. Weuster-Botz. Tang. 12 (2010) 518-525.J. Y. A. Li. Yan. Metabolic evolution of two reducing equivalent-conserving pathways for high-yield succinate production in Escherichia coli. Z. Chen. Li. Van Heerden. Lin. S. Kamzolova. Sonomoto. 101 (2010) 8493-8501. 6 (2013) 426. N. Finogenova. S. Bioresour Technol.-O.P. Q. Mixed food waste as renewable feedstock in succinic acid fermentation.A. in: M. N. R. Jamshidi. Pfaltzgraff. Thermal characterization of polylactides. H. Aurich.A. Appl Microbiol Biotechnol. Food waste as a valuable resource for the production of chemicals. [52] C. Energy Environ Sci. Herrero-Davila. Recent advances in lactic acid production by microbial fermentation processes. T. 83 (2009) 1027-1034. Appl Microbiol Biotechnol. Clark. Yusupova. Muller. L. Morgunov. Kim.H.V.A.R & D for 21 . S. Sineoky. Appl Biochem Biotechnol. R. A. Matsui. W.S. K. Hyon. Gao. L. Nair. Dickson.-W. L. Q.V. N. An overview of the recent developments in polylactide (PLA) research. N. Mohamed. Ionic liquid pretreatment to increase succinic acid production from lignocellulosic biomass. Jost. Vybornaya. Luque. Bioresour Technol. Ryu. O.A.Y. Fukui. Larina. C. R. H. Ikada. T. Vinokurova. Chemically assisted microbial production of succinic acid by the yeast Yarrowia lipolytica grown on ethanol. K.V. Du. 29 (1988) 2229-2234. Q. Kondrashova. Abderrahim.[51] C.B. Kang. Q. Liang.P. [60] K. C. Wee. R. [62] T. Sun. Laptev. Y. Y. 107 (2010) 673-682. materials and fuels. Holz. Biotechnol Adv. Biotechnol Bioeng.-J. Sun. Koutinas. G. Brocklesby. K. D.A. Kang. Kopsahelis. Wang. T.G. Current situation and global perspective. The influence of oxygen limitation for the production of succinic acid with recombinant strains of Yarrowia lipolytica. J. Madhavan Nampoothiri. Polymer. A. Thankappan. K. Lin. J. Wang. [54] B. Li. 99 (2014) 1675-1686. John. Lin. T.V. Yuzbasheva. Sanna. Qi.G. Y.I. I. 174 (2014) 1822-1833. 172 (2014) 283-289. Yan. Z.I. 31 (2013) 877-902.H. Bley. S. The current status and future expectations in industrial production of lactic acid by lactic acid bacteria. Stamatelatou. 44 (2006) 6.R. [61] M. M. Sobolevskaya. Abdel-Rahman. E. E.) Lactic Acid Bacteria . A. Xing. Tashiro.N. Yuzbashev. Bioresour Technol. M. Heikki. Barth. Li.I.S.K. F. Production of succinic acid at low pH by a recombinant strain of the aerobic yeast Yarrowia lipolytica. [59] K. RKY2 using corn steep liquor as a nitrogen source Food Technol Biotechnol. Qi. M. Kongo (Ed. Wang. Q. Fedotcheva.S. Mubofu. [53] S. [56] Z. [57] Z. [58] Y. J. A. [55] T. Production of succinate and polyhydroxyalkanoate from substrate mixture by metabolically engineered Escherichia coli. 102 (2011) 6600-6604. I. Pilot-scale lactic acid production via batch culturing of Lactobacillus sp. Electron J Biotechnol. [70] S. Ramchandran. Hofvendahl. Enzym Microb Technol.-K. M. A. Franco. A. l-lactic acid production from whole wheat flour hydrolysate using strains of Lactobacilli and Lactococci. Mathews.R. Ingram.-M. 73 (2001) 25-34. 38 (2003) 1573-1583. pp. I.K. 59 (2002) 160-169. x. Madzingaidzo.-G. Duke.T. Z. Biotechnol Lett. P. Chang. Biochem Eng J. substrate. C. S. [68] W.N. M. L (+) lactic acid fermentation and its product polymerization. W.P. Krištofı. R. L. Middelberg. Chang.. 24 (1999) 191-199. Biotechnol Lett.-M.5% from 2014-20: Grand View Research (2014). Process Biochem. Bai. Neureiter. M. [72] M. Kwon. M. Appl Microbiol Biotechnol. Zhang. Roychoudhury. Srivastava. Thermophilic production of lactic acid using integrated membrane bioreactor systems coupled with monopolar electrodialysis. [65] D. Braun. and oxygen. Zhao.J. Xu. Fick. J Membr Sci. Schlosser. 18 (2004) 41-48. A. [71] J. [64] N. Broome. I. ková. Ou.P.-M. Lactic acid production by Bacillus coagulans—kinetic studies and optimization of culture medium for batch and continuous fermentations. W. L. [66] A. InTech2013. P. Fermentation of sugar cane bagasse hemicellulose hydrolysate to l(+)-lactic acid by a thermotolerant acidophilic Bacillus sp. T. Strain improvement of Rhizopus oryzae for over-production of l(+)-lactic acid and metabolic flux analysis of mutants.O. Enzym Microb Technol. L. K. X. C. Rosenberg. [63] SpecialChem. Lee. Sabolová. E. 22 . Lactic acid production from lactose by Lactobacillus plantarum: kinetic model and effects of pH. [74] L. Biotechnol Bioeng.M. Patel. [69] K. M.K. Š. Growth and lactic acid production in batch culture of Lactobacillus rhamnosus in a defined medium.G. Vasiljevic. Yoo. Y. Thomasser. cremoris by a novel submerged membrane fermentation process.M. [73] T. Fermentation of lactic acid with Rhizopus arrhizus in a stirred tank reactor with a periodical bleed and feed operation. B. Sanciolo. Danner. M. Berry. High-rate continuous production of lactic acid by Lactobacillus rhamnosus in a two-stage membrane cell-recycle bioreactor. Narayanan. 21 (1999) 163-167. [67] H. H. Marták. 3 (1999) 163-170. 26 (2004) 865-868. Li. 20 (1997) 301-307. 403–404 (2012) 179-187. Improving cell yield and lactic acid production of Lactococcus lactis ssp. Chemaly. Powell. amp. Health and Livestock Purposes. Payot.Food. 7 (2004) 13. 670. Global lactic acid market to grow at a CAGR of 15. Fu. Hahn-Hägerdal. Biochem Eng J. Shanmugam. X. [83] J. Y. Walczak. J. Le Gal (Eds. 1. [80] S. Park. [87] J. Productivity and economics of a continuous membrane bioreactor. Gallezot. Efficient production of L-lactic acid using co-feeding strategy based on cane molasses/glucose carbon sources. M. 73 (2015) 52-61. C. Oltuszak-Walczak. 1 (2006) 1428-1432. Gas chromatographic and spectroscopic analysis 23 . Continuous mode lactic acid fermentation based on renewables. and economical aspects. M. Venus. Chem Soc Rev. E. Biotechnol J. L. Faria-Machado. roles as biomarkers. Beppu. Res J Biotechnol. Cheryan. pp.R.) Mar Biotechnol. 43 (1995) 242248. Shamala. A. Karimi. Xylose fermentation to optically pure l-lactate by isolates of Enterococcus faecium.A. 2012.-P. Degradation of starchy substrates by a crude enzyme preparation and utilization of the hydrolysates for lactic fermentation. Enzymatic-based hydrolysis processes for ethanol. Vieira. [84] J. Enzym Microb Technol. 2 (2007) 32. [85] A. Yahiro. Rygala. Bu. Lin. Kosakai. Ulber.T. 153 (2014) 23-29. Okabe. 9 (1987) 726-729. Ziegler.K. [82] M.J.R.A. M. K. 236 (2013) 365-371. 4 (2009) 15-22. Epoxidation of modified natural plasticizer obtained from rice fatty acids and application on polyvinylchloride films. Tang. M. A. Y. Fatty acids from lipids of marine organisms: Molecular biodiversity. R. Xu. [88] E. A. Schneider. Czyzowska. Venus. [76] P. Pleissner. P. Venus. 49-125. [77] P. Jiang. Springer Berlin Heidelberg2005. Food Res Int. [78] D. Appl Microbiol Biotechnol. Utilization of renewables for lactic acid fermentation. Sreekantiah. Akintayo. J Ferm Bioeng. He. K. Pietraszek.Y. 84 (1997) 249-253. Conversion of biomass to selected chemical products. Fatty acid feedstock preparation and lactic acid production as integrated processes in mixed restaurant food and bakery wastes treatment.M. da Silva.G. [86] P. Yin.F. M. pp. New Biotechnol. Bioresources. J. biologically active compounds. Barnathan.S. N. T. 41 (2012) 1538-1558. in: R. [81] T. Tejayadi. Onipede. G. Y. Enhanced production of L(+)-lactic acid from corn starch in a culture of Rhizopus oryzae using an air-lift bioreactor. 127 (2013) 3543-3549. [79] K. Lactic acid from cheese whey permeate. Eur Food Res Technol. K. Taherzadeh. A. P. Dybka. Lau. Bioresour Technol. L(+)-Lactic acid production from furfural residues and corn kernels with treated yeast as nutrients.[75] Y. Xu. K. Otlewska. Nishina. Bergé. J Appl Poly Sci. K. J. Koivuranta. Kim. The spent cake from olive oil filtration as biomass feedstock. Y. W. Pleissner. Alvarez.-G. Biotechnol Bioeng. A matter of detail: Assessing the true potential of microalgal biofuels. Food Hydrocolloid. Fats and oils as oleochemical raw materials. [95] D. P. 1 (2013) 1-6. [91] D. Lewis.J. Mutjé.-W. Tornabene. 16 (2014) 156-160. M. G. 135 (2013) 357-364. Food Res Int. Valorization of winery and oil mill wastes by microbial technologies.J. [92] Y. Ind Crop Prod. T. J Phycol. S.M. J. 24 .H. [100] J. Guerrini. [98] J. Rodríguez-Gutiérrez. FernándezBolaños. 1 (2012) 40-48. Biotechnol Adv.S. Agr Eng Int: CIGR Journal. Romero-Garcia. Lipid production in batch and fed-batch cultures of Rhodosporidium toruloides from 5 and 6 carbon carbohydrates. Negro.R. [90] A. [101] I. [99] P.G. A. State of the art and future trends. J. High-cell-density cultivation of oleaginous yeast Cryptococcus curvatus for biodiesel production using organic waste from the brewery industry. Sust Chem Proc. Bioresour Technol. Nino. Choi. Lamsal. L. [94] D. Lama-Muñoz. nitrogen. [93] D. C. [96] B. Castro. 72 (2000) 10. 72 (2015) 183-191. J. Benemann. Boufi. C. 109 (2012) 2005-2016. A. and carbon limitation on biomass composition in batch and continuous flow cultures of the heterotrophic dinoflagellate Crypthecodinium cohnii. K. Bull Chem Soc Ethiop. 25 (2007) 294-306. Y. [89] K. García. Hill. Maicas. Penttilä. Klein-Marcuschamer. [97] M. S. Algal Res. Chisti. Mitra. Biotechnol Bioeng. 50 (2015) 237-246. J. Thomas.-E.T. Rubio-Senent. Martinez-Patino. Naghmouchi. Lin. 21 (1985) 72-81. J. [102] F. 73 (2015) 13-25. Chisti. Yang. A. Masella. Kim. Eriksen. Parenti. BMC Biotechnol 12 (2012) 10. Bioresour Technol. M. 110 (2013) 23172322. Effects of phosphorous. van Leeuwen. Biodiesel from microalgae. Ruohonen. D.G. E. Pure Appl Chem. B.-I. Novel pectin present in new olive mill wastewater with similar emulsifying and better biological properties than citrus pectin. Ben-Amotz.of epoxidized canalo oil. N. Biorefinery based on olive biomass. L. Heterotrophic/mixotrophic cultivation of oleaginous Chlorella vulgaris on industrial co-products. Ryu. J. Wiebe. Pleissner. Valorisation of food waste in biotechnological processes. Mateo. C. K. Chemical profile of selected species of microalgae with emphasis on lipids. L. Olive stones flour as reinforcement in polypropylene composites: A step forward in the valorization of the solid waste from the olive oil industry. Han.K. 159 (2014) 421-432. 20 (2006) 11. [114] X.K. M. P. K. Bioresour Technol. Algal Res. J. Zhang. W. B. S. Cardona. Semenčenko. Valorization of agricultural residues for compactin production by Aspergillus terreus MTCC 279 in mixed substrate solid state fermentation. Neureiter. Xia. [110] R. [106] A. Kuglarz. [112] J. Wurz. New Biotechnol. Obruca. [105] M.V. Smerilli. 90 (2015) 648-657. J. J. Patnaik.Y. Haznedaroglu. [111] L. 5 (2014) 529-549. Montazeri.2015. Naranjo. Mukhopadhyay. Seraman. Rajendran.A.10. Fruhauf. (2015). 73 (2015) 75-80. 133 (2006) 251-262. Higuita. S. Petrik. Radosavljević. Mallick. Shen.V. 12 (2015) 328-336. [104] M. S. ChemSusChem. [109] M.C. Karakashev.1016/j. J. Integrated production of cellulosic bioethanol and succinic acid from industrial hemp in a biorefinery concept. Biotechnological conversion of spent coffee grounds into polyhydroxyalkanoates and carotenoids. De. Direct fermentation of potato starch and potato residues to lactic acid by under non-sterile conditions. L. C. Use of residual banana for polyhydroxybutyrate (PHB) production: Case of study in an integrated biorefinery. Waste Biomas Valor. Soh. 31 (2015) 717-727.[103] D. Peccia. Thangavelu. 5 (2014) 715-724. Kucera.D.D.K. J Chem Technol Biotechnol. Bioresour Technol. Appl Biochem Biotechnol.Z. Waste Manage. Benesova.P. Pleissner. A.S. Integration of poly-3-(hydroxybutyrate-co-hydroxyvalerate) production by Haloferax mediterranei through utilization of stillage from rice-based ethanol manufacture in India and its techno-economic analysis.M. Lin. U.and algal biomass-derived lipids. M. I. I. C. 25 .081. Lactic acid production from cellulosic material by synergetic hydrolysis and fermentation. 34 (2014) 2634-2640. 8 (2015) 1686-1691. S. N. L.biortech. C. Kelly. Effective valorisation of distillery stillage by integrated production of lactic acid and high quality feed. [107] A. M. V. Mojović. Plasticizer and surfactant formation from food-waste. C. Pejin. Waste Biomas Valor. S. Fuchs. P.B. Haas. Christakopoulos. Mamma. V. Mukherjee. Bhowmic. Food Res Int. C. Bhattacharyya. World J Microbiol Biotechnol. Zimmerman. S. Syed. Angelidaki. A. [108] S. J. Lau. Jana. Haldar. (2016) doi: 10. D. M. D.M. Eckelman. [113] D. Utilization of Scenedesmus obliquus biomass as feedstock for biodiesel and other industrially important co-products: An integrated paradigm for microalgal biorefinery.B. Marova. Kocić-Tanackov. Biotransformation of citrus by-products into value added products. Alvarado-Morales. 151 (2014) 19-27. M. Evaluating microalgal integrated biorefinery schemes: Empirical controlled growth studies and life cycle assessment. K. Djukić-Vuković.J. S. Z. Zhang. [120] J. R. Y. Y.-W. Dong. 25 (2003) 1161-1164. Ouyang. J. D. Z. J.S. Chen. Whey fermentation by Anaerobiospirillum succiniciproducens for production of a succinate-based animal feed additive. 102 (2011) 6147-6152. Fang. Chen. 149 (2013) 84-91. Y. J. P. [119] C. L. 101 (2010) 7889-7894. Zheng. J. Lin. S. P. Appl Biochem Biotechnol.-J.-K. S. U. [123] K. Zheng. torquens. Simultaneous saccharification and fermentation of acid-pretreated rapeseed meal for succinic acid production using Actinobacillus succinogenes. Jiang. Dong.-Y. A. Biotechnol Lett. J Sust Bioen Syst. Koutinas. Zeikus. A. Xu. M. L.G. Y.-H. Miao. Ke-Quan. L. Enhanced succinic acid production from sake lees hydrolysate by dilute sulfuric acid pretreatment and biotin supplementation. Wei. M. Hodge. W. Belén Moldes. Ma. Du. Ni. P. K. P. Effect of different carbon sources on the production of succinic acid using metabolically engineered Escherichia coli. Chen. X. 48 (2011) 339-344.-H. K. Sun. Jain. Jiang.-L. [125] R. Yáñez. Wan. J.-Y. Wei. 99 (2008) 8310-8315. Y. Dai. [126] M. Jiang. Biotechnol Prog 23 (2007) 381-388.[115] R. Ye-Lian. Efficient succinic acid production from lignocellulosic biomass by simultaneous utilization of glucose and xylose in engineered Escherichia coli. A.C. [121] P. R. 145 (2008) 111-119.-Q. Xiu. Production of D(−)-lactic acid from cellulose by simultaneous saccharification and fermentation using Lactobacillus coryniformis subsp. Li. [116] C. Wu. F. Liu. Alonso. J. Y. Dorado.-Q. [122] P. Liu. Min. M. Parajó. Z. J. M. C. Fang. K. Fermentative production of succinic acid from straw hydrolysate by Actinobacillus succinogenes. Bioresour Technol. Succinic acid production from cellobiose by Actinobacillus succinogenes.-J. [124] C. Xu. Succinic acid production from cheese whey using Actinobacillus succinogenes 130 Z. Li. Jie-Yu. M. Bioresour Technol. Bioresour Technol.K. Xi. Li. Shahbazi. Samuelov.-J. J. K. Succinic acid production from corn stover by simultaneous saccharification and fermentation using Actinobacillus succinogenes. 26 . Rova. Fang. S. J. Wei. Zheng.-H. P. P. 65 (1999) 2260-2263. [118] C. H. X. Bioresour Technol. 100 (2009) 2425-2429. Han. Chen. C. Liang. R. Bioresour Technol. A complete industrial system for economical succinic acid production by Actinobacillus succinogenes. Ni.K. Wan. Appl Environ Microbiol. Chen. 2012 (2012). Zhang. Ouyang. Webb. [117] N. Sun. Wang.-J. Andersson. Datta. Bioresour Technol. A wheat biorefining strategy based on solid-state fermentation for fermentative production of succinic acid. Wei. Y. Berglund. Enzyme Microb Technol. P.A. G. John. Generation of succinic acid in culture. Lee. [136] R. [132] D. Pérez-Chabela.G. Zhu. Yim. H. P. Appl Microbiol Biotechnol. J Ind Microb Biotechnol. Liu. Q. Sanville-Millard. 2004. N. 35 (2004) 648-653. S. 170 (2014) 491498. Y. Lactic acid production from hemicellulosic hydrolyzate by cells of Lactobacillus bifermentans immobilized in Ca-alginate using response surface methodology. Lee. Lactic acid production from waste sugarcane bagasse derived cellulose. Z. recover succinic acid. Bioresour Technol. [135] M. Madhavan Nampoothiri. Roca. Carvalho. 37 (2010) 1137-1143. Green Chem. Reis. V. Chang. Appl Biochem Biotechnol. Simultaneous saccharification and fermentation of cassava bagasse for l-(+)-lactic acid production using Lactobacilli. Donnelly. J.M. Duchiron. Pandey. Succinic acid production from orange peel and wheat straw by batch fermentations of Fibrobacter succinogenes S85. 134 (2006) 263-272. Bennett. In vitro fermentation of 27 . F. [133] M. Wang. Mayorga-Reyes.N. S. [129] Q. 88 (2010) 671-678. Yan. Siles. Efficient production of lactic acid from sucrose and corncob hydrolysate by a newly isolated Rhizopus oryzae GY18. H. [128] C. M. X. Economical succinic acid production from cane molasses by Actinobacillus succinogenes.-H. Park. [127] Y. San. propagate.V. Production of succinic acid by engineered E.Y. D. Jiang. Batch and continuous fermentation of succinic acid from wood hydrolysate by Mannheimia succiniciproducens MBEL55E.Y. 25 (2003) 111114. Zheng. Kim. [130] M.C. C.-P. 24 (2008) 745-752. Li. accumulate biomass. 99 (2008) 1736-1742. coli strains using soybean carbohydrates as feedstock under aerobic fermentation conditions. K.-J. A. Guo. metabolize hydrolysate. Sun. obtain mutant cells. C. World J Microb Biot. S. S.P. Dong. [131] P. I.C. [138] A.Y. Gokhale. C. 9 (2007) 58-62.J. Biological conversion of wood hydrolysate to succinic acid by Anaerobiospirillum succiniciproducens. Lee.N. Nghiem. [137] Y. [134] S. Varma.A. A. Hong. Z. Adsul. Ni.135 (2013) 469-474. Chang. Lee. Teng. Bioresour Technol. G. L. Biotechnol Lett. Carob pod water extracts as feedstock for succinic acid production by Actinobacillus succinogenes 130Z. P. M. L. Bioresour Technol. K. Thakker. J. Givry. S. 130 (2013) 398-405.-L.-Y. Lee.I. Parra-Matadamas. Google Patents. Thompson. Prevot. Enz Microb Technol. W. Rentschler. and determination of the antioxidant activities of the extracts. Schieber.A. Storage stability of a high dietary fibre powder from orange by‐products.V. Hilt. J. Yamazumi. Endreß. Pleissner. A.) seed oil production as a valuable source of phenolic antioxidants. Ohkouchi. Y.A. [148] J. Lin. [146] T. T. Appl Biochem Biotechnol. R. Shirai. Biotechnol Lett. Direct production of l(+)-lactic acid from starch and food wastes using Lactobacillus manihotivorans LMG18011. P. Schieber.L. Yener.-J. Yun. Ryu.Y. M. A new process for the combined recovery of pectin and phenolic compounds from apple pomace.S. [140] Y. Fernández‐López. Berardini. J Supercrit Fluids. Int J Food Sci Technol. Y. Carle. cactus pear peel and pineapple peel by lactic acid bacteria.R. Kammerer. [147] A. S. Selective proliferation of lactic acid bacteria and accumulation of lactic acid during open fermentation of kitchen refuse with intermittent pH adjustment. R. M. M. P. Simon. 43 (2007) 55-63. E. Sendra‐Nadal. D. Y. C. 170 (2014) 144-151. A closed loop for municipal organic solid waste by lactic acid fermentation. Viuda‐Martos. Identification of flavonol and xanthone glycosides from mango (Mangifera indica L. Cv. In Food Res J. Alvarez. Iyer. D. Tau. Tanumihardjo. Inoue. Carotenoid profiles and 28 . N. Bayındırlı. 26 (2004) 71-74. Surles. 84 (2000) 665-677. High-yield fermentation of pentoses into lactic acid. Y. J. Moriguchi. Carle. Park.P. 6 (2000) 140-145. Biotechnological production of L (+)lactic acid from wood hydrolyzate by batch fermentation of Enterococcus faecalis. Inno Food Sci Emerg Technol.O. S. Adil. Navarro.-W. H. [142] Y. H. Pümpel. D. 22 (2015) 859-865. [143] K.-U. N. Subcritical (carbon dioxide+ ethanol) extraction of polyphenols from apple and peach pomaces. J Agric Food Chem. Lee. A. [145] A. Sayas. Maier. Schieber.“Tommy Atkins”) peels by high-performance liquid chromatography-electrospray ionization mass spectrometry. 97 (2006) 15541562. Residues of grape (Vitis vinifera L. Y. [144] K. Wee.-S. Sakai. 51 (2003) 5006-5011. [139] P. 4 (2003) 99-107. J. Food Chem. H. Thomas. Weng. Insam. [150] R. Probst. 44 (2009) 748-756. Bioresour Technol. H. Murata.-H. A. Mori. [149] I. C. E. 175 (2015) 142-151. Recycling of food waste as nutrients in Chlorella vulgaris cultivation. Food Sci Technol Res. R.K. Lau. 112 (2009) 551-559. [141] M. M. C. Cetin.H. Bioresour Technol.agroindustrial by-products: grapefruit albedo and peel. Streker. H. Bioresour Technol. Carle. P. Wagner.W. Walde. T. M. 78 (2002) 319-324. 52 (2004) 3417-3421. Analyses of tomato peel and seed byproducts and their use as a source of carotenoids. Changes in nutraceutical composition of lemon juices according to different industrial extraction systems. Llorach. S. Onions: a source of unique dietary flavonoids. J Agric Food Chem. Conrad. Vågen. Espín. 55 (2007) 10067-10080. Knoblich. J. [157] R. Tanumihardjo. Tringali. Daquino. Ruberto. J Sci Food Agric. 57 (2009) 4142-4147. Uribesalgo. V. C. [153] G.) of various colors. De Tommasi. Valorization of cauliflower (Brassica oleracea L. Food Chem. [154] N. J Agric Food Chem. Simon. Amico.C. L. anthocyanins. Fezer. 85 (2005) 1166-1170. P. U. C. Spatafora. 51 (2003) 2181-2187. Fossen.consumer sensory evaluation of specialty carrots (Daucus carota. botrytis) by-products as a source of antioxidant phenolics. [152] F. Screening of mango (Mangifera indica L. Anderson. F. [155] T. [151] M. Food Chem. Schieber.A. [156] R. Polyphenol constituents and antioxidant activity of grape pomace extracts from five Sicilian red grape cultivars. Beifuss. Carle. and pectin. C. 53 (2005) 1563-1570. Berardini. R. Antioxidant phytochemicals and antioxidant capacity of biofortified carrots (Daucus carota L. var. Tomás-Barberán. Marın.) cultivars for their contents of flavonol O-and xanthone Cglycosides. Castillo. M. I. F.) of various colors. 29 . Martinez.M. D. Frutos. B. Slimestad. R. A. J Agric Food Chem. S. Renda.A. J Agric Food Chem. J. A. Latshaw. T. J Agric Food Chem. Ferreres. 100 (2007) 203-210. Sun.W. N. Figure 1. 30 . Industrially relevant metabolites obtainable via fermentative processes [1]. the oxidative pathway and the reductive pathway of the tricarboxylic acid (TCA) cycle.Figure 2. including the glyoxylate shunt. Pathways involved in succinic acid production. 31 . respectively. Continuous cultivation of Lactobacillus paracasei with biomass ( ) retention for lactic acid ( ) production at increasing dilution rate ( ). 32 .Figure 3. Glucose ( ) and nitrogen source were obtained from barley hydrolysate and green press juice. Chemical conversion of saturated and unsaturated fatty acids into biodiesel and bio-plasticizer.Figure 4. 33 . respectively [113]. 34 .Figure 5. Major pathways of polyunsaturated fatty acid biosynthesis starting from acetylCoA [87]. lactic acid and bio-plasticizer from food waste. 35 . into lactic acid. The remaining nitrogenrich compounds from algal biomass production and lipid extraction would be sufficient to convert 1.917.Figure 6. Integrated biorefinery concept for the production of succinic acid. Figures are based on dry weights.5 kg glucose (*obtainable from cellulose and hemicellulose-rich agricultural residues). trace minerals [21. gelatine. 22] Dairy products Carbon and nitrogen sources [22] Waste oil Fatty acid methyl esters. glycerol. erucic acid [23] Cellulosic biomass Phytosterols. lipids. 25] 36 .Table 1. phenols. isobutanol. thioester. carotenoids. nitrogen source. phytochemicals. collagen. Organic residues and their applications. adipic acid [24. flavonoids. acrylic acid. meat and derivatives Proteins. Organic residues Application Ref. polypropylene. Fruits and vegetables Antioxidants. esters [23] Lignin Polyhydroxyalkanoates. carbon source [22] Animal waste. enzymes. 86 0. succinogenes Cheese whey NA A.3 1. coli A.19 0.16 0.60 NA [116] 34. succiniciproducens Glucose.91 - [117] 19.66 NA [116] - 0.3 - 0. coli Fructose NA Rec.12 1.87 0. coli Xylose NA Rec. coli NA Rec. oryzae A. Xylose Raw whey (lactose) A.8 - 0.58 NA [116] - 0.83 NA [116] - 1.50 NA [116] - 0.28 [14] 31. bench top bioreactor Batch/bench top bioreactor 37 Final conc.Table 2. E.78 0. oryzae A. succinogenes Food waste Wheat-based feedstock Waste bread Cakes Pastries Rec.02 - - [117] 29. E. awamori and A. oryzae A.7 0.80 0.80 - [117] 34.22 [56] 64. succinicproducens Cheese whey NA A.8 0.44 0.2 1.9 0.01 0. succinogenes A. awamori and A. succinicproducens Cheese whey NA A. - 1. Feedstock Pretreatment Microorganisms Glucose NA Rec. E.succinogenes A. awamori and A. E.81 - [118] 47. Comparison of succinic acid production from conventional media and organic residues. succinogenes Configuration Batch/bench top bioreactor Batch/bench top bioreactor Batch/bench top bioreactor Batch/bench top bioreactor Batch/bench top bioreactor Fed-batch Batch/bench top bioreactor Batch/bench top bioreactor Batch/bench top bioreactor Batch/bench top bioreactor Batch/Bench top bioreactor Batch/bench top bioreactor Fed-batch/bench top bioreactor Continuous. coli NA Rec. E.79 0. awamori and A.60 - [117] 27.67 0. succinicproducens Cheese whey NA A.48 0.35 [14] 34.56 0. coli NA A. E. awamori and A. oryzae A.79 0.7 1. Fructose Glucose.55 [49] 24. oryzae A.57 - [119] . [g L-1] Productivity [g L-1 h-1] Yield [g g-1 sugar] Yield [g g-1 waste] Ref.27 0.9 0.7 - 0. 5 0.65 - [126] Acid.21 - [122] A.59 - [124] Rec.97 0.12 - [123] A.61 0.succinogenes Batch/bench top bioreactor 45.72 - [121] A.33 0.73 - [120] A.1 - 0.83 1. Aqueous ammonia soaking Alkaline + enzymatic hydrolysis Alkaline + enzymatic hydrolysis A.6 - 0.succinogenes Anaerobic bottle 19.Corn stover Corn stover Corn straw Corn straw Alkaline + enzymatic hydrolysis Alkaline. potassium ferrocyanide. succinogenes Batch/bench top bioreactor 56.3 0.0 - 0. succinogenes Batch/bench top bioreactor 46.74 - [122] A.6 1.81 - [122] A.4 0.2 0.succinogenes Batch/bench top bioreactor 20 0.4 - 0. Alkaline peroxide.63 - [122] A.succinogenes Anaerobic bottle 17.95 0.4 - 0. E coli Fed-batch/bench top bioreactor 39.89 - [122] A. resin A.79 - [127] Corn core hydrolysate Rice straw hydrolysate Wheat straw hydrolysate Rapeseed meal Sake lees Sugar cane bagasse hydrolysates Cellobiose & sugars from sugarcane bagasse cellulose hydrolysates Sugar cane molasses Acid + enzymatic hydrolysis Acid + enzymatic hydrolysis 38 .succinogenes SSF 15. succinogenes SSF 47.succinogenes Anaerobic bottle 32.21 0.succinogenes Batch/bench top bioreactor 61.5 - 0.97 - [125] Acid + enzymatic hydrolysis A. Acid.succinogenes Fed-batch/bench top bioreactor 53. potassium ferrocyanide. succinogenes Batch /bench top bioreactor 24. E.54 - [130] Steam explosion + enzymatic hydrolysis Steam explosion + enzymatic hydrolysis Steam explosion + enzymatic hydrolysis A.9 0. resin and activated carbon Acid hydrolysis Acid hydrolysis Wheat straw NA Orange peel Steam distillation + acid hydrolysis Rec.19 0.0 - - - [129] 1. succinogenes Sugar cane molasses Wood hydrolysate Wood hydrolysate Wood hydrolysate Plant hydrolysates (industrial grade hydrolysates) A.15 - - [127] 11.55 - [132] - Rec. succiniciproducens Batch/bench top bioreactor 11.56 - [132] M. E. bench top bioreactor 8.88 - [131] M.Soybean meal Soy solubles and activated carbon Acid.64 - [128] [128] 2.05 [129] - 1.0 - 0.2 1.2 36.0 3.00 - [133] 39 .61 0.03 - 0.0 1.8 - 0. coli - 72.64 0. coli Fibrobacter succinogenes Fibrobacter succinogenes Carob pod water extracts - A. coli Rec.7 1. succinogenes Fed-batch/bench top bioreactor Batch/flask Batch/flask Batch/serum bottles Batch/serum bottles Batch/bench top bioreactor 55.00 1.17 0. E. succiniciproducens Continuous. 0 - 0.0 - [83] 40 . - L.3 2.83 [134] 168.0 - 0.0 - 0.3 - [83] - L. coagulans - L. paracasei Continuous/ hollow fibre membrane reactor 60. Comparison of lactic acid production from conventional media and organic residues.84 [78] Batch/conical flasks - - 0.92 [73] Batch/bench top bioreactor 32.8 - 0.Table 3.1 0.0 25.47 [134] 62. coagulans food waste fermentation Defatted algal Proteolytically biomass and defatted pretreated defatted food B. [g L-1] Productivity [g L-1 h-1] Yield [g g-1 sugar] Batch/bench top bioreactor 55.84 [78] Batch/bench top bioreactor 37.94 [81] Batch/test tubes 41.0 3. biferementans hydrolysate Wheat bran hydrolysate Cane molasses/glucose Barley hydrolysate and green juice from alfalfa Barley hydrolysate and green juice from alfalfa Configuration Final conc. paracasei Batch 100. Feedstock Pretreatment Sucrose/Yeast NA Bacillus coagulans extract Defatted algal Fungal enzymes in biomass and defatted submerged B.3 - 0.88 [79] Microorganisms Batch/cell immobilization by calcium alginate beads Fed-batch/bench top bioreactor Ref. biferementans - B. coagulans food waste waste derived solids Lactobacillus Ragi and wheat bran Enzymatic hydrolysis plantarum Wheat bran L. Sugarcane bagasse Cassava bagasse Corncob hydrolysates Steam + alkali + enzymatic hydrolysis Enzymatic hydrolysis Acid + enzymatic hydrolysis NaCl scalding + milling and sieving L.80 [139] Wood hydrolysate Acid hydrolysis. Steam explosion.11 [142] 27-45 - - [143] Grapefruit albedo Municipal solid wastes Kitchen waste Homogenizing Kitchen waste - Batch L. delbrueckii SSF - 1.1 - - [138] Soft wood Acid hydrolysis L. pH intermittently brevis neutralized predominantly 41 . L. viridans Batch/flask 2.2 - - [138] Batch/flask 2.4 - [136] Rhizopus oryzae Batch/flask 97.79 - [141] 48.83 [135] L. Commercial enzymes Enterococcus faecalis Batch/bench top reactor 24-93 1.93 0.7 - 1.2 - [140] Blending L. viridans Milling and sieving A.81 - [137] Batch/flask 2.7-3.4 - - [138] Grapefruit peel Milling and sieving Pineapple peel Opuntia ficus fruit peel Milling and sieving Aerococcus viridans Pediococcus pentosaceus A.5 0.4 - - [138] Batch/flask 2. manihotivorans L. acidophilus Fed-batch - 0. Batch. rhamnosus Batch/bottle - 0. delbrueckii SSF 67. phantarnm.38 0. casei susp.0 0. 1 0.2 1.6 0.3 0.c Food waste Food waste 0.d Thin stillage Thin stillage 4. aBatch culture. vulgarisa.2 [144] C.1 [13] C.2 [78] S.e C.6* - [96] Yeasts C. bFed-batch culture.2 0.1 [95] C. d Grown under mixotrophic conditions. mangroveia. vulgarisa.1 0.e.8* 1.Table 4.0 1.c Food waste Food waste 9.c Food waste Food waste 1. Lipid concentration and productivities of lipids and unsaturated fatty acids (UFAs) of various microalgal strains cultivated in presence of organic residues as carbon and/or nitrogen sources.9 [13] 8.1* 3. eCultivation carried out at a C/N ratio of 20.8 1. curvatus a.2 0.6 0. Algae C.6* - [96] 19.2 0.9 [95] C. Microbes Carbon source Nitrogen source Lipid concentration Lipid productivity UFA productivity [g L-1] [g L-1 d-1] [g L-1 d-1] Ref.d Soy whey Soy whey 0.c Food waste Food waste 2. fCultivation carried out at a C/N ratio of 35 42 . pyrenoidosab. curvatusa.f Spent yeast lysate / Spent yeast glycerol lysate Spent yeast lysate / Spent yeast glycerol lysate *Based on quantified fatty acid methyl esters. vulgarisa.2 2. pyrenoidosaa. cGrown under heterotophic conditions. grape pomace.Table 5. carrot pomace. 157] 43 . Phytochemical compound Fruit and vegetable residues Ref. mango peel. onion waste [153-156] Hydroxycinnamic acids Orange pomace. lemon pomace. mango peel. carrot pomace. tomato pomace. onion wastes [145] Flavonoids Apple pomace. onion waste [145-148] Carotenoids Peach peel. Phenolic acids Apple pomace. grape pomace. lemon pomace [149-152] Anthocyanins Apple pomace. Phytochemicals in fruit and vegetable residues. carrot pomace. cauliflower by-products [148.