Growth engineering of Propionibacterium freudenreichii shermanii for organic acids and other value-added products formation

Propionic acid production from glucose was studied using Propionibacterium freudenreichii shermanii. Conditions were optimized for high yields of propionic acid and total organic acids by sequential optimization of parameters like pH, inoculum age, inoculum volume and substrate concentration. Near-theoretical yield (0.54?±?0.023?g/g) was achieved for propionic acid with fermentation of 1% glucose using 20% (v/v) of 48?hr old P. shermanii at 30°C, pH maintained at 5.5. Total organic acid yield under these conditions was 0.74?±?0.06?g/g. The study resulted in achieving 98% and 95% theoretical yields of propionic acid and total organic acids, respectively. Under optimized conditions, along with organic acids, P. shermanii also produced vitamin B12 and trehalose intracellularly, showing its potential to be used as a cell factory.     

Utilization of horticultural waste (Apple Pomace) for multiple carbohydrase production from Rhizopus delemar F2 under solid state fermentation

The brown rot fungus Rhizopus delemar F₂ was shown to produce extracellular thermostable and multiple carbohydrase enzymes. The potential of Rhizopus delemar F2 in utilizing apple pomace under solid state fermentation (SSF) is the purpose of the study. Solid state fermentation (SSF) is a very effective technique opposed to submerged fermentation in various aspects. Enhanced production of multiple carbohydrases 18.20?U?g^?1 of cellulose, 158.30?U?g^?1 of xylanase, 61.50?U?g^?1 of pectinase and amylase 21.03?U?g^?1 was released by microwave pretreatment of apple pomace at 450?W for 1?min and then by incubation the culture thus obtained at 30?°C for 6 days with moisture content of 1:4.5. Apple pomace can serve as a potential source of raw material for the production of multiple carbohydrases. Besides, it can find great commercial significance in production of bioethanol and various industries like textile, fruit juice, paper and pulp industry.     

Effect of High-Dose Nano-selenium and Selenium–Yeast on Feed Digestibility, Rumen Fermentation, and Purine Derivatives in Sheep

The aim of this study was to evaluate the effect of nano-selenium (NS) and yeast?Cselenium (YS) supplementation on feed digestibility, rumen fermentation, and urinary purine derivatives in sheep. Six male ruminally cannulated sheep, average 43.32?±?4.8?kg of BW, were used in a replicated 3?×?3 Latin square experiment. The treatments were control (without NS and YS), NS with 4?g nano-Se (provide 4?mg Se), and YS with 4?g Se-yeast (provide 4?mg Se) per kilogram of diet dry matter (DM), respectively. Experimental periods were 25?days with 15?days of adaptation and 10?days of sampling. Ruminal pH, ammonia N concentration, molar proportion of propionate, and ratio of acetate to propionate were decreased (P?<?0.01), and total ruminal VFA concentration was increased with NS and YS supplementation (P?<?0.01). In situ ruminal neutral detergent fiber (aNDF) degradation of Leymus chinensis (P?<?0.01) and crude protein (CP) of soybean meal (P?<?0.01) were significantly improved by Se supplementation. Digestibilities of DM, organic matter, crude protein, ether extract, aNDF, and ADF in the total tract and urinary excretion of purine derivatives were also affected by feeding Se supplementation diets (P?<?0.01). Ruminal fermentation was improved by feeding NS, and feed conversion efficiency was also increased compared with YS (P?<?0.01). We concluded that nano-Se can be used as a preferentially available selenium source in ruminant nutrition.     

Candida zeylanoides as a new yeast model for lipid metabolism studies: effect of nitrogen sources on fatty acid accumulation

Lipid homeostasis is well-known in oleaginous yeasts, but there are few non-oleaginous yeast models apart from Saccharomyces cerevisiae. We are proposing the non-oleaginous yeast Candida zeylanoides QU 33 as model. The aim of this study was to investigate the influence of the carbon/nitrogen ratio and the type of nitrogen source upon oil accumulation by this yeast grown on shake flask cultures. The maximum biomass was obtained in yeast extract (2.39?±?0.19 g/l), followed by peptone (2.24?±?0.05 g/l), while the highest content of microbial oil (0.35?±?0.01 g/l) and the maximum lipid yield (15.63 %) were achieved with peptone. Oleic acid was the predominant cellular fatty acid in all culture media (>32.23 %), followed by linoleic (>15.79 %) and palmitic acids (>13.47 %). The highest lipid yield using glucose and peptone was obtained at the C/N ratio of 200:1.     

Protease production by thermo-alkaliphilic novel gut isolate Kitasatospora cheerisanensis GAP 12.4 from Gryllotalpa africana

In course of searching for proteolytic microbes from the gut of Gryllotalpa africana, a potent isolate GAP 12.4 was screened and identified as Kitasatospora cheerisanensis having protease activity 46.8?±?1.52?U/ml. Optimum conditions for the protease production (605.3?±?9.7?U/ml) were 7-d cultivation, 5% inoculum, pH 9.5, 55?°C, 150?rpm, and supplementation with 0.8% glucose and 0.6% ammonium sulfate. Surfactants such as SDS, EDTA, Tween 80 and Triton X-100 showed positive effect on enzyme production. Addition of biotin (50?μg/ml) promotes enzyme production maximally (674.15?±?4.13?U/ml). Further enhancement on addition of casein hydrolysate and molasses to the production medium was 709.20?±?7.53?U/ml and 744.26?±?9.71?U/ml, respectively. The isolate was also able to utilize agro-industries waste, green gram husk in solid-state fermentation for enzyme production (1675.02?±?21.58?U/ml). This thermo-alkaliphilic isolate may be a potent candidate for low cost protease production through management of agro-residues. It is the first report of protease production by a member of actinobacteria under the Kitasatospora genus.     

Biosynthesis regulation of natamycin production from Streptomyces natalensis HDMNTE-01 enhanced by response surface methodology

Natamycin has been widely applied in medical treatments and food protection widely due to its effective inhibition to the growth of yeast and mold. As polyene macrolide antibiotic, the biosynthesis pathway of natamycin is relatively clear. To regulate the biosynthesis of natamycin, additions of precursors affecting cell growth and natamycin production were investigated. The results showed that 0.003% (w/v) potassium ferrocyanide and sodium propionate: n-butanol at a ratio of 4:1 was added into the broth at 0 and 24?hr, respectively, and they contributed to yield natamycin, reaching 1.62?g?L^?1 (174.6% higher than control). Furthermore, response surface methodology was undertaken to enhance natamycin production by Streptomyces natalensis HDMNTE-01 (a wild strain). The optimum conditions determined were: glucose 3.97%; soya peptone 2%; yeast extract 0.5%; original pH 7.0; inoculum volume 6%; growth in a 250-mL flask containing 24.68?mL of medium; shaken (220?rpm) at 28°C for 4 days. Under the optimized conditions, the yield was 2.81?g?L^?1 natamycin in 5-L fermentor when the fermentation was processed.     

Cost-effective and concurrent production of industrially valuable xylano-pectinolytic enzymes by a bacterial isolate Bacillus pumilus AJK

Simultaneous production of xylanase and pectinase by Bacillus pumilus AJK under submerged fermentation was investigated in this study. Under optimized conditions, it produced 315?±?16 IU/mL acidic xylanase, 290?±?20 IU/mL alkaline xylanase, and 88?±?9 IU/mL pectinase. The production of xylano-pectinolytic enzymes was the highest after inoculating media (containing 2% each of wheat bran and Citrus limetta peel, 0.5% peptone, 10?mM MgSO₄, pH 7.0) with 2% of 21-hr-old culture and incubated at 37°C for 60?hr at 200?rpm. Xylanase retained 100% activity from pH 6.0 to10.0 after 3?hr of incubation, while pectinase showed 100% stability from pH 6.0 to 9.0 even after 6?hr of incubation. Cost-effective and concurrent production of xylanase and pectinase by a bacterial isolate in the same production media suggests its potential for various biotechnological applications. This is the first report of simultaneous production of industrially important extracellular xylano-pectinolytic enzymes by B. pumilus.     

Synthesis of geranyl propionate in a solvent-free medium using Rhizomucor miehei lipase covalently immobilized on chitosan–graphene oxide beads

The chemical route of producing geranyl propionate involves the use of toxic chemicals, liberation of unwanted by-products as well as problematic separation process. In view of such problems, the use of Rhizomucor miehei lipase (RML) covalently bound onto activated chitosan–graphene oxide (RML-CS/GO) support is suggested. Following analyses using Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetry, properties of the RML-CS/GO were characterized. A response surface methodological approach using a 3-level-four-factor (incubation time, temperature, substrate molar ratio, and stirring rate) Box–Behnken design was used to optimize the experimental conditions to maximize the yield of geranyl propionate. Results revealed that 76?±?0.02% of recovered protein had yielded 7.2?±?0.04?mg?g^?1 and 211?±?0.3%?U?g^?1 of the maximum protein loading and esterification activity, respectively. The actual yield of geranyl propionate (49.46%) closely agreed with the predicted value (49.97%) under optimum reaction conditions (temperature: 37.67°C, incubation time: 10.20?hr, molar ratio (propionic acid:geraniol): 1:3.28, and stirring rate: 100.70?rpm) and hence, verifying the suitability of this approach. Since the method is performed under mild conditions, the RML-CS/GO biocatalyst may prove to be an environmentally benign alternative for producing satisfactory yield of geranyl propionate.     

Carboxymethyl cellulase production optimization from Glutamicibacter arilaitensis strain ALA4 and its application in lignocellulosic waste biomass saccharification

Abstract

In this context, carboxymethyl cellulase (CMCase) production from Glutamicibacter arilaitensis strain ALA4 was initially optimized by one factor at a time (OFAT) method using goat dung as proficient feedstock. Two-level full factorial design (2⁵ factorial matrix) using first-order polynomial model revealed the significant (p?<?0.05) influence of pH, moisture, and peptone on CMCase activity. Central composite design at N?=?20 was further taken into account using a second-order polynomial equation, and thereby liberated maximum CMCase activity of 4925.56?±?31.61?U/g in the goat dung medium of pH 8.0 and 100% moisture containing 1% (w/w) peptone, which was approximately two fold increment with respect to OFAT method. Furthermore, the partially purified CMCase exhibited stability not only at high pH and temperature but also in the presence of varied metal ions, organic solvents, surfactants, and inhibitors with pronounced residual activities. The enzymatic hydrolysis using partially purified CMCase depicted the maximum liberation of fermentable sugars from alkali pretreated lignocellulosic wastes biomass in the order of paddy straw (13.8?±?0.15?mg/g)?>?pomegranate peel (9.1?±?0.18?mg/g)?>?sweet lime peel (8.37?±?0.16?mg/g), with saccharification efficiency of 62.1?±?0.8, 40.95?±?0.4, and 37.66?±?0.4%, respectively after 72?hr of treatment.     

Influence of pH on butyrate uptake and solvent fermentation by a mutant strain of Clostridiumacetobutylicum

The effect of pH (between 4.4 and 6.6) on butyrate uptake by the mutant strain of Clostridium acetobutylicum was studied using the fermentation broth from fermentor-2 (solventogenic stage) of a two-fermentor continuous system. Low pH (?1 butyrate, under batch incubation at 30?°C, was not inhibited at pH?>?5.2, however, at pH??1. Batch incubation at relatively higher temperatures (35° and 37?°C) indicated a similar trend i.e., a pH of >5.5 was required for uptake of >8?g l^?1 butyrate. Optimization studies for butyrate uptake by C. acetobutylicum suggested a direct correlation between minimum pH and butyrate concentration or temperature. The role of undissociated butyric acid appears to be critical in regulation of butyrate uptake.     

Cyanophycin production from feather hydrolysate using biotechnological methods

Abstract

Cyanophycin is a bacterial storage polymer for carbon, nitrogen and energy with emerging industrial applications. As efficient cyanophycin production is enhanced by peptone, but commercial peptones are very expensive, thereby increasing the overall production cost, an enzymatically produced feather hydrolysate (FH) is assessed as a cheap replacement of peptone to lower the costs and make cyanophycin production more economically feasible. Keratinase production using feather as the sole carbon/nitrogen source by S.pactum 40530 at 30-L fermentation scale was achieved within 93?h with degradation rate of 96.5%. A concentration of 60?g/L of FH, generated by keratinolytic activity (8?×?10³?U?g^?1L^?1d^?1) within 24?h, was used as the main carbon/peptone source to produce cyanophycin. The growth performances of E. coli DapE/L using FH was compared to that of casamino acids (CA) and up to 7.1?±?0.4 and 5.3?±?0.3?g/L of cell mass were obtained after 72?h from FH and CA, respectively. Cyanophycin production yielded 1.4?±?0.1g/L for FH with average molecular mass of 28.8 and 1.4?±?0.2 for CA with average molecular mass of 35.3, after 60?h. For the first time, FH generated by biotechnological methods from environmentally problematic, abundant and renewable feather bioresource was successfully used for cyanophycin biopolymer production.     

Optimization of cellulase-free xylanase production by alkalophilic Cellulosimicrobium sp. CKMX1 in solid-state fermentation of apple pomace using central composite design and response surface methodology

Microbial xylanases and associated enzymes degrade the xylans present in lignocellulose in nature. Xylanase production by Cellulosimicrobium sp. CKMX1, isolated from mushroom compost, produced a cellulase-free extracellular endo-1, 4-β-xylanase (EC 3.2.1.8) at 35 °C and pH 8.0. Apple pomace—an inexpensive and abundant source of carbon—supported maximal xylanase activity of 500.10 U/g dry bacterial pomace (DBP) under solid state fermentation. Culture conditions, e.g., type of medium, particle size of carbon source, incubation period, temperature, initial pH, and inoculum size, were optimized and xylanase activity was increased to 535.6 U/g DBP. CMCase, avicelase, FPase and β-glucosidase activities were not detected, highlighting the novelty of the xylanase enzyme produced by CKMX1. Further optimization of enzyme production was carried out using central composite design following response surface methodology with four independent variables (yeast extract, urea, Tween 20 and carboxymethyl cellulose), which resulted in very high levels of xylanase (861.90 U/g DBP). Preliminary identification of the bacterial isolate was made on the basis of morphological and biochemical characters and confirmed by partial 16Sr RNA gene sequencing, which identified CKMX1 as Cellulosimicrobium sp. CKMX1. A phylogenetic analysis based on the 16Sr RNA gene sequence placed the isolate within the genus Cellulosimicrobium, being related most closely to Cellulosimicrobium cellulans strain AMP-11 (97% similarity). The ability of this strain to produce cost-effective xylanase from apple pomace on a large scale will help in the waste management of apple pomace.     

Valorization of Hemicelluloses: Production of Bioxylitol from Poplar Wood Prehydrolyzates by <Emphasis Type="Italic">Candida guilliermondii</Emphasis> FTI 20037

In this study on the valorization of hemicelluloses (a co-product generated during cellulosic bioethanol production), prehydrolyzates obtained from poplar woodchips pretreated in an industrial experimental steam-explosion pilot-plant facility were evaluated for the production of bioxylitol using the yeast, Candida guilliermondii FTI 20037, employing both batch and fed-batch fermentation modes in shake flasks on defined nutrient medium. The prehydrolyzates consisted of monosaccharides (pentose and hexose sugars) as well as xylo-oligosaccharides and undegraded hemicellulose. Xylose (31.6?±?0.57 g/L) was the major sugar in the prehydrolyzates that also contained acetic acid and degradation products of lignin and sugars (phenolic and furanic compounds). Xylose in the prehydrolyzates could be further increased (106.4?±?0.02 g/L) through an acid hydrolysis step (0.6 % (w/v) H₂SO₄). Compounds of a toxic nature in both the acid hydrolyzates and prehydrolyzates were removed by treatment with Amberlite IRA-400 resin (chloride form). Batch fermentation of pure xylose and poplar prehydrolyzate resulted in bioxylitol production of 9.9?±?0.01 and 4.9?±?0.17 g/L, respectively, indicating that the poplar prehydrolyzates exhibited an inhibitory effect on fermentation. After detoxification of the poplar prehydrolyzates, bioxylitol production increased to 8.9?±?0.01 g/L. Fed-batch fermentation of the prehydrolyzate increased the bioxylitol production to 12.39?±?0.33 g/L, while acid hydrolysis followed by detoxification resulted in a maximum bioxylitol production of 22.0?±?0.01 g/L, a 348 % increase. The results demonstrated that acid hydrolysis and detoxification followed by fed-batch fermentation was an efficient way to produce bioxylitol from poplar prehydrolyzates.     

Addition of citrus pulp and apple pomace in diets for dogs: influence on fermentation kinetics,digestion, faecal characteristics and bacterial populations

Fermentation kinetics, digestibility, faecal characteristics and bacterial populations (aerobes, anaerobes, lactobacilli, lactic acid bacteria, enterococci, coliforms and clostridia) of dog food mixed with citrus pulp and apple pomace were evaluated. The in vitro gas production of a pre-digested dog food mixed with 0, 30, 50 and 70 g/kg dry matter (DM) of citrus pulp or apple pomace was measured, and also an experiment with dogs fed the same dog food with or without the addition of 70 g/kg of either fresh citrus pulp or apple pomace was conducted. Gas production increased linearly (p < 0.001) and quadratically (p < 0.001) as fibre levels augmented. The inclusion of fibre sources in the diets resulted in higher faecal output (p = 0.005) and defecation frequency (p < 0.001), and lower faecal pH (p < 0.001) and digestibility values (p < 0.01). Faecal consistencies and microbial populations did not differ among treatments. The addition of fresh citrus and apple was effective to stimulate the hindgut fermentation, but slightly depressed the digestion.     

Optimization of production conditions for β-mannanase using apple pomace as raw material in solid-state fermentation

Apple pomace is a wasted resource produced in China in large quantities, disposal of which has caused serious environmental problems. In order to make the best of this residue, apple pomace together with cottonseed powder was used as a raw material to produce β-mannanase in solid-state fermentation (SSF) by Aspergillus niger SN-09. Optimization of fermentation conditions for maximizing β-mannanase production was carried out using Plackett-Burman and Central Composite designs. A mixture of apple pomace and cottonseed powder (3:2, w/w) with 59.2 % (w/w) initial moisture, together with certain ionic compounds and salts, proved to be the optimal medium. The test fungi were inoculated in the optimized medium and incubated at 30°C for 48 h. The activity of β-mannanase reached 561.3 U/g, an increase of 45.7 % compared with that in basal medium, and reached the same level of production as that achieved using wheat bran and soybean meal as raw materials as in most factories in China. This is the first report of the use of apple pomace as a raw material to produce β-mannanase in SSF. This will not only reduce the production cost of β-mannanase, but also represents a new and effective way to make the best use of apple pomace, which can consequently help to reduce the environmental pollution caused by this waste.     

Total phenolic and flavonoid contents and antioxidant activity of ginger (Zingiber officinale Rosc.) rhizome,callus and callus treated with some elicitors

The present study was aimed at determining total phenolic and flavonoid contents and studying the antioxidant activity of ginger (Zingiber officinale Rosc.) rhizome and callus, 6-gingerol and 6-shogaol and callus treated with elicitors. Petroleum ether (PE) and chloroform: methanol (1:1, v/v) (CM) extracts were prepared by maceration. Highest total phenolic content was obtained from the CM extract (60.34?±?0.43?mg gallic acid/g) of rhizome while callus showed lower content detected in the CM extract (33.6?±?0.07?mg gallic acid/g). Flavonoids were only detected in rhizome (CM extract 40.25?±?0.21?mg quercetin/g). Both rhizome extracts exhibited good antioxidant activity with higher activity recorded in PE extract (IC₅₀ value 8.29?±?1.73?μg/mL). Callus extracts revealed lower antioxidant activity (IC₅₀ value 1265.49?±?59.9?μg/mL obtained from CM extract). 6-gingerol and 6-shogaol displayed high antioxidant activity in both assays with IC₅₀ 4.85?+?0.58_DPPH and 5.35?±?0.33_ABTS μg/mL for the former and IC₅₀ 7.61?±?0.81_DPPH and IC₅₀ 7.05?±?0.23_ABTS μg/mL for the latter. Treatment of callus with elicitors showed significant (p?<?0.05) effects in enhancing phenolic content and related antioxidant activity. The highest significant increase in phenolic content (37% and 34%) and antioxidant activity in DPPH assay (34% and 30%) was observed in callus treated with 100?mg/L yeast extract and 50?mg/L salicylic acid respectively. Therefore, studying the effect of the elicitation of ginger cultured tissues in phenolic accumulation would be of immense importance for pharmacological, cosmetic and agronomic industries.     

Probiotic Properties and Cellular Antioxidant Activity of <Emphasis Type="Italic">Lactobacillus plantarum</Emphasis> MA2 Isolated from Tibetan Kefir Grains

Lactobacillus plantarum MA2 was isolated from traditional Chinese Tibetan kefir grains. Its antioxidant properties had been demonstrated in vitro and in vivo previously. In the present study, the probiotic characteristics of this strain were further evaluated by investigating its acid and bile salt tolerances, cell surface hydrophobicity, and autoaggregation, respectively. In addition, the cellular antioxidant activity (CAA) assay was applied to test the antioxidant capacity of the isolate in different growth phases. Same method was also used to evaluate the antioxidant capacity of its fermentation supernatant, cell-free extract, and intact cell quantitatively. The results of probiotic characteristic tests showed that MA2 could survive at pH 2.5 and 0.3% bile salt. Meanwhile, the measurements of cell surface hydrophobicity and autoaggregation were 45.29?±?2.15 and 6.30?±?0.34%, respectively. The results of cellular antioxidant activity tests indicated that MA2 had high antioxidant potential. The CAA value of logarithmic phase cell-free extract of MA2 (39,450.00?±?424.05 μmol quercetin equivalents/100 g sample) was significantly higher than that in stationary phase cell-free extract (3395.98?±?126.06 μmol quercetin equivalents/100 g sample) and that of fermentation supernatant in logarithmic phase (2174.41?±?224.47 μmol quercetin equivalents/100 g sample) (p?<?0.05). The CAA method was successively applied to evaluate the antioxidant capacity of MA2 in this study, which suggests that it could be used as a useful method for lactic acid bacteria antioxidant potential evaluation.     

Use of response surface methodology to optimize protease synthesis by a novel strain of Bacillus sp. isolated from Portuguese sheep wool

Aims: To investigate the influence of yeast extract, peptone, temperature and pH upon protease productivity by Bacillus sp. HTS102 – a novel wild strain isolated from wool of a Portuguese sheep breed (Merino). Methods and Results: A 2⁴ full factorial, central composite design together with response surface methodology was used to carry out the experiments and analyse the results, respectively. Among the individual parameters tested, temperature and peptone concentration produced significant effects upon protease productivity. A high correlation coefficient (R² = 0·994, P < 0·01) indicated that the empiric second‐order polynomial model postulated was adequate to predict said productivity, with the optimum loci characterized by: temperature of 43°C, peptone content of 1·4 g l^?1, pH of 5·1 and yeast extract concentration of 10·0 g l^?1. Conclusions: Protease synthesis depends chiefly on temperature and peptone level. The maximum protease activity was more than twice that obtained with the basal medium, so the experimental design and analysis undertaken were effective towards process optimization. Significance and Impact of the Study: Rational choice of processing conditions for maximum protease productivity will be relevant if an economically feasible fermentation process based on Bacillus sp. HTS102 is intended.     

A novel recycle batch immobilized cell bioreactor for propionate production from whey lactose

Recycle batch fermentations using immobilized cells of Propionibacterium acidipropionici were studied for propionate production from whey permeate, de-lactose whey permeate, and acid whey. Cells were immobilized in a spirally wound fibrous sheet packed in a 0.5-L column reactor, which was connected to a 5-L stirred tank batch fermentor with recirculation. The immobilized cells bioreactor served as a breeder for these recycle batch fermentations. High fermentation rates and conversions were obtained with these whey media without nutrient supplementation. It took approximately 55 h to ferment whey permeate containing approximately 45 g/L lactose to approximately 20 g/L propionic acid. Higher propionate concentrations can be produced with various concentrated whey media containing more lactose. The highest propionic acid concentration obtained with the recycle batch reactor was 65 g/L, which is much higher than the normal maximum concentration of 35 to 45 g/L reported in the literature. The volumetric productivity ranged from 0.22 g/L . h to 0.47 g/L . h, depending on the propionate concentration and whey medium used. The corresponding specific cell productivity was 0.033 to 0.07 g/L . g cell. The productivity increased to 0.68 g/L . h when whey permeate was supplemented with 1% (w/v) yeast extract. Compared with conventional batch fermentation, the recycle batch fermentation with the immobilized cell bioreactor allows faster fermentation, produces a higher concentration of product, and can be run continually without significant downtime. The process also produced similar fermentation results with nonsterile whey media. (c) 1995 John Wiley & Sons, Inc.     

Immobilization of co-culture of Saccharomyces cerevisiae and Scheffersomyces stipitis in sodium alginate for bioethanol production using hydrolysate of apple pomace under separate hydrolysis and fermentation

Apple pomace as a substrate for bioethanol production is interesting due to its abundance and sustainable availability in varied states like Himachal Pradesh (H.P.), Jammu and Kashmir, Uttarakhand and Arunachal Pradesh, India. In the current study, apple pomace which is the main fruit industrial waste of H.P. was evaluated as feedstock for bioethanol production by the process of enzymatic saccharification using multiple carbohydrases. Microwave pretreatment of the apple pomace resulted in the efficient removal of lignin and crystalline structure of cellulose fibre. The enzymatic saccharification of the pretreated biomass was done by optimizing parameters for maximal saccharification leads to production of 27.50?mg/g of reduce, ng sugar. An enhanced ethanol yield of 44.46?g/l and fermentation efficiency of 58% by immobilized co-culture of Saccharomyces cerevisiae MTCC 3089 and Scheffersomyces stipitis NCIM 3498 under SHF as compared to fermentation performed with free yeast cells, i.e. 34.46?g/l of ethanol and 45% of fermentation efficiency.