Generating Fermentable Sugars from Rice Straw Using Functionally Active Cellulolytic Enzymes from Aspergillus niger HO (original) (raw)
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Cellulases can be used for biofuel production to decrease the fuel crises in the world. Microorganisms cultured on lignocellulosic wastes can be used for the production of cellulolytic enzymes at large scale. In the current study, cellulolytic enzyme production potential of Aspergillus fumigatus was explored and optimized by employing various cultural and nutritional parameters. Maximum endoglucanase production was observed after 72 h at 55 °C, pH 5.5, and 70 % moisture level. Addition of 0.3 % of fructose, peptone, and Tween-80 further enhanced the production of endoglucanase. Maximum purification was achieved with 40 % ammonium sulfate, and it was purified 2.63-fold by gel filtration chromatography. Endoglucanase has 55 °C optimum temperature, 4.8 optimum pH, 3.97 mM K m , and 8.53 μM/mL/min V max. Maximum exoglucanase production was observed at 55 °C after 72 h, at pH 5.5, and 70 % moisture level. Further addition of 0.3 % of each of fructose, peptone, and Tween-80 enhances the secretion of endoglucanase. It was purified 3.30-fold in the presence of 40 % ammonium sulfate followed by gel filtration chromatography. Its optimum temperature was 55 °C, optimum pH was 4.8, 4.34 mM K m , and 7.29 μM/mL/min V max. In the case of β-glucosidase, maximum activity was observed after 72 h at 55 °C, pH 5.5, and 70 % moisture level. The presence of 0.3 % of fructose, peptone, and Tween-80 in media has beneficial impact on β-glucosidase production. A 4.36-fold purification was achieved by 40 % ammonium sulfate precipitation and gel filtration chromatography. Optimum temperature of β-glucosidase was 55 °C, optimum pH was 4.8, K m was 4.92 mM, and V max 6.75 μM/mL/min. It was also observed that fructose is better than glucose, and peptone is better than urea for the growth of A. fumigatus. The K m and V max values indicated that endoglucanase, exoglucanase, and β-glucosidase have good affinity for their substrates.
Cellulase Production by Aspergillus Flavus and Saccharification of Wheat Straw
Cellulase production from fungal sources is utilized in the processing of lignocellulosic biomass for production of alternative fuels. Biomass selection is an important consideration in commercial production of cellulase. Wheat straw is a cheap and readily available substrate with potential for bioconversion. The production of cellulase using wheat straw as substrate and subsequently saccharification was investigated in this study. Rapid production of cellulase viz. FPase & CMCase derived from Aspergillus flavus was observed. Maximum activity of FPase 167 IU/g and CMCase 415IU/g was obtained after 96h of incubation with cellulose as co-substrate and pH 4.5. Highest saccharification yield was with 25gL-1 (72%) substrate though higher concentration of wheat straw inhibited enzyme activity. The study suggests that production of cellulase from Aspergillus flavus using low cost wheat straw as substrate can be an alternative for large scale low cost enzyme production.
Isolation, Optimization and Production of Cellulase by Aspergillus niger from Agricultural Waste
Cellulases are the group of hydrolytic enzymes such as endoglucanase (CMCase), exoglucanase, β β β β β-glucosidase (BGL) and FPase which are responsible for release of sugars in the bioconversion of the cellulosic biomass into a variety of value-added products. The cellulase producing fungi were isolated from various agriculture fields. Total 21 isolates were obtained on Czapek's Dox agar medium. Aspergillus niger was selected as most efficient enzyme producer by screening technique. Optimization of some nutritional and environmental factors like nitrogen source, temperature, pH and fermentation time were studied under submerged culture condition for cellulolytic enzyme production. Different agriculture waste material was used as carbon source. Maximum cellulolytic activity was observed in 4.2 pH media at 28°C after 96 hours in submerge condition. Wheat straw showed maximum activity of CMCase, exoglucanase, β β β β β-glucosidase and FPase were 8.38 IU/ml, 5.21 IU/ml, 0.30 IU/ml and 8.08 IU/ml, respectively followed by baggase.
Polish Journal of Microbiology Polskie Towarzystwo Mikrobiologow the Polish Society of Microbiologists, 2013
This study was aimed to evaluate the pattern of cellulase biosynthesis from Aspergillusfumigatus ABK9 under submerged fermentation. Production was increased concomitantly with fungal growth up to 72 h and reached maximum (Xmax -6.72 g/l) with specific growth rate (mu max) of 0.126/h. Highest specific rate of enzyme production (q ) was found at initial medium pH of 5.0 and incubation temperature of 30 degrees C. At the same time, in the presence of 2-deoxy-D-glucose concentration of 0.5 mg/ml, the production of cellulolytic enzymes, viz, carboxymethyl cellulase activity (CMCase), filter paper degrading activity (FPase) and P-glucosidase activity reached maximum of 132.2, 21.3 and 28.9 U/ml, respectively. Cellulase biosynthesis was induced in respect to higher volumetric production rate (Qp), specific rate of enzymes production (qp, U/g biomass/h) and enzyme/biomass yield (YE/X) when grown in carboxymethyl cellulose in comparison to other saccharides as sole carbon source. Induction ratios (IR) of cellulases were between 12.3 and 24.4 in the presence of 1.5% (w/v) CMC in the culture media. The strain was quite resistant to catabolic repression by glucose up to 0.4% (w/v). Cellulases production was greatly influenced in the presence of yeast extract and potassium dihydrogen phosphate (KH2POA) as nitrogen and phosphate sources in the culture media. C/N ratio of 10.0 and C/P ratio of 4.0 proved to be the best for the production of enzyme cocktail. Along with the high production yield, the crude enzymes showed a promising cellulose hydrolyzing efficiency of rice straw, indicating the enzyme could be beneficial for its large scale industrial exploitation.
Background: Production of cellulose-degrading enzymes from Aspergillus terreus D34 using different growth substrates was studied under solid-state cultivation. We have tested two lignocellulosic biomass residues viz., rice straw (RS) and sugarcane bagasse (BG), both separately and in combinations, and crystalline cellulose as a sole source of carbon for cellulase production. We also demonstrated different cellulase cocktail formulations and enzymatic saccharification studies on mild-alkali and dilute-acid pretreated RS- and BG-biomass residues. Results: Substrate-specific non-denaturing native gels showed two exoglucanases, four endoglucanases, three β-glucosidases, and four xylanases in the microbial culture extract of RS-grown cells. While in the BG-culture extract, two exoglucanases, five endoglucanases, three β-glucosidases, and four xylanases were detected. Similarly, in crystalline cellulose-grown culture extract, three exoglucanases, four endoglucanases, one β-glucosidase, and two xylanases were detected. However, the cellulase compositions were highly varied with the culture extracts obtained from the mixed biomass (RSBG) growth substrate. We found that few enzymes were specifically induced while others were repressed in RSBG-grown cultures. Enzymatic saccharification resulted in the production of maximum reducing sugars of 0.733 and 0.498 g g−1 with mild-alkali treated RS- and BG-biomass residues with saccharification yields reaching up to 82.8% ± 1.0% and 59.3% ± 1.7%, respectively. Conclusions: The cellulase activities, namely FPase, CMCase, avicelase, β-glucosidase, and endoxylanase, were significantly higher in the BG-grown culture extract. Optimization of microbial growth carbon sources produced an efficient cellulase enzyme cocktail mixture with an approximately twofold higher total cellulase (FPase) activity that drastically reduced the required amount of enzyme (in terms of unit volumes) for enzymatic hydrolysis studies.
Cellulase production by Aspergillus niger on different natural lignocellulosic substrates
Cellulases are the group of hydrolytic enzymes Filter paperase (FPase), Carboxymethylcellulase (CMCase) and -glucosidase (BGL) and are responsible for release of sugars in the bioconversion of the lignocellulosic biomass into a variety of value - added products. The present study was aimed to examine cellulase production by Aspergillus niger on individual lignocellulosic substrates in both submerged (SmF) and solid State (SSF) Fermentations. Rice bran supported maximum enzyme yields followed by wheat bran in both fermentations. Among different combinations with rice bran at equal ratio (1:1w/w) tested, combination of rice bran and wheat bran served the best combination for production of cellulolytic enzymes. Maximum titers of FPase, CMCase and BGL obtained on this combination were 2.632, 2.478 and 2.984 U/mL in SmF and 29.81, 25.2 and 32.18 U/gDS in SSF respectively
Bioresource technology, 2017
The aim of this work was to characterize cellulase from Aspergillus tubingensis NKBP-55 for generation of fermentable sugars from agricultural residues. The strain produced high titres of cellulase (750 U/gds) on copra meal in solid state fermentation (SSF). The enzyme preparation also showed hemicellulolytic activities (U/gds) viz. endo-mannanase (1023), endo-xylanase (167), β-glucosidase (72) and α-galactosidase (54). Zymography revealed presence of six cellulases, six mannanases and one β-glucosidase. It effectively degraded sugarcane bagasse (SCB) and rice straw (RS) releasing xylose, glucose and cellobiose. One cellulase (Cat 1, Mr ∼65 kDa) was purified and characterized. It retained more than 50% activity at 70 °C after 150 mins and its activity was enhanced in the presence of Mn2+ ions (130%) and β-mercaptoethanol (140%). FTIR and 13C CP/MAS NMR analysis of the enzyme treated SCB and RS revealed degradation of cellulose and hemicellulose, while 1H and 13C liquid state NMR exp...
3 Biotech, 2015
Different agricultural residues were considered in this study for their ability to support cellulolytic enzyme production by Aspergillus niger. A total of eleven agricultural residues including finger millet hulls, sorghum hulls, soybean hulls, groundnut husk, banana peels, corn stalk, cassava peels, sugarcane bagasse, saw dust, rice straw and sheanut cake were subjected to three pretreatment (acid, alkali and oxidative) methods. All the residues supported the growth and production of cellulases by A. niger after 96 h of incubation. Maximum cellulase production was found in alkali-treated soybean hulls with CMCase, FPase and b-glucosidase yields of 9.91 ± 0.04, 6.20 ± 0.13 and 5.69 ± 0.29 U/g, respectively. Further studies in assessing the potential of soybean hulls are being considered to optimize the medium composition and process parameters for enhanced cellulase production.
Sugarcane bagasse as carbon source for the production of cellulase by Aspergillus niger
BIOMED natural and applied science
Background: In the presence of a suitable carbon source, filamentous fungi such as Aspergillus species are particularly important in enzyme production for industrial scale. The conversion of hemicelluloses from agro-waste biomass into valuable products has been considered strategic for the economic viability and bedrock of lignocellulose biorefineries. Methods: In the present study, we explore the potential of Aspergillus niger and Aspergillus flavus to utilized 3 agro-waste including sugarcane bagasse (SB), plantain pseudostem (PS), and corn cob (CC) as carbon sources for cellulase production, and determine the optimum yielding condition. Results: The results revealed that among the 3 agro-waste explored, SB was the most suitable carbon source utilized by A. niger and A. flavus for cellulase production. The maximum activity ranges of 205.03±3.25 and 302.13±2.56 IU/mL were obtained after 24 hr of fermentation with the SB. The optimum temperature, pH, and substrate concentrations wer...