Biotechnological production and statistical optimization of fungal xylanase by bioconversion of the lignocellulosic biomass residues in solid-state fermentation (original) (raw)
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Bioscience Journal, 2016
This study reports the optimization of xylanase production under solid state fermentation (SSF) by a thermotolerant Aspergillus fumigatus strain (SCB4) isolated from sugarcane bagasse piles of Brazilian Cerrado. Different combinations of low-cost agricultural byproducts in SSF were evaluated: sugarcane bagasse and wheat bran (1:1), sugarcane bagasse and corn straw (1:1) and only sugarcane bagasse. The enzyme biosynthesis by SSF was carried out at different temperatures (40, 45, 50 and 55 o C). The maximum levels of xylanase activity were obtained after 24 h at 45 °C using a culture medium containing sugarcane bagasse and wheat bran (1:1). Under optimal conditions, the fungal culture produced 574 U g-1 of xylanase (units/g of dry substrate). The crude enzyme showed optimal activity at 60 °C and pH 4.5. It exhibited thermostability up to 55 °C, wide range of pH stability and tolerance to ethanol, xylose and glucose. The physicochemical properties shown by this enzyme are appropriate for its application in hydrolysis of lignocellulosic residues for ethanol production and other bioproducts.
Food Technology and …, 2008
Xylanase was produced by Aspergillus niger LPB 326 cultivated on lignocellulosic substrate composed by sugarcane bagasse and soybean meal in solid-state fermentation. The effects of various variables were observed and optimized by applying statistical experimental designs. The best xylanase activity was obtained in a medium containing 10 g of sugarcane bagasse and soybean meal in the ratio of 65 and 35 %, respectively, moistened to 85 % of initial water content with a nutrient salt solution composed of (in g/L): CuSO 4 0.4, KH 2 PO 4 1.5 and CoSO 4 0.0012, and incubated for 4 days at 30°C. Under these optimized conditions, a xylanase activity of 3099 IU/g of dry matter was obtained.
Optimization of nutritive media composition for xylanase production by Aspergillus awamori
2007
Optimization of nutritive media composition for xylanase production by Aspergillus awamori RUS-8 was carried out. Full adequate regression model was obtained by Central Composition Plan. Maximum xylanase activity was achieved in optimized nutritive media on a following composition (g/L): wheat bran-20.02; corn cobs-30.85; corn steep liquor-20.38; NaNO 3-2.20; KH 2 PO 4-1; KCl-0.5; MgSO 4-0.5 and FeSO 4-0.01.
Bioresources, 2017
Xylanase is a key enzyme in the conversion of lignocellulosic biomass into various oligosaccharides and simpler monomeric units through the hydrolysis of hemicellulose. Rice straw is readily available around the world and is a rich source of hemicellulose. Recently, there has been growing interest in the exploitation of rice straw as a low-cost substrate for the production of hemicellulolytic enzyme, i.e., xylanase. This study aimed to optimize the nutritional components (rice straw, magnesium sulphate, and calcium chloride concentrations) and physical parameters (temperature and pH) for xylanase production with a newly isolated Aspergillus oryzae LC1 under submerged fermentation using central composite design based response surface methodology. The optimum media constituents were 1% rice straw (w/v), 1.0 g/L calcium chloride, and 0.3 g/L magnesium sulphate, and the optimum physical parameters were pH 5 and 25 °C. The statistical design showed increased xylanase production with a ma...
Biochemical Engineering Journal, 2010
Xylanase production by Aspergillus foetidus MTCC 4898 was carried out under solid state fermentation using wheat bran and anaerobically treated distillery spent wash. Response surface methodology involving Box-Behnken design was employed for optimizing xylanase production. The interactions among various fermentation parameters viz. moisture to substrate ratio, inoculum size, initial pH, effluent concentration and incubation time were investigated and modeled. The predicted xylanase activity under optimized parameters was 8200-8400 U/g and validated xylanase activity was 8450 U/g with very poor cellulase activity. Crude xylanase was used for enzymatic saccharification of agroresidues like wheat straw, rice straw and corncobs. Dilute NaOH and ammonia pretreatments were found to be beneficial for the efficient enzymatic hydrolysis of all the three substrates. Dilute NaOH pretreated wheat straw, rice straw and corncobs yielded 4, 4.2, 4.6 g/l reducing sugars, respectively whereas ammonia treated wheat straw, rice straw and corncobs yielded 4.9, 4.7, 4.6 g/l reducing sugars, respectively. The hydrolyzates were analysed by HPTLC. Xylose was found to be the major end product with traces of glucose in the enzymatic hydrolyzates of all the substrates.
The production of extracellular xylanase by a locally isolated strain of Aspergillus flavus FPDN1 was studied for optimization of cultural conditions and saccharification followed by bioethanol production. Among the various agro residues used pearl millet (bajara) bran was found to be the best for high activity of xylanase with poor cellulase production under solid state fermentation with compared to submerged fermentation. During optimization, influence of different cultural conditions such as substrate concentration, incubation period, moisture level, inoculum size, pH, temperature, effect of carbon sources, orgenic and inorganic nitrogen sources were investigated. The production of the xylanase reached at maximum with substrate concentration (4g), incubation period (5 day), moisture level (45%), inoculum size (3 x 106 spores/mL), pH (6), temperature (250C), carbon source (xylose), organic nitrogen source (yeast extract) and inorganic nitrogen source [(NH4)2SO4]. Under optimized c...
Bioprocess and Biosystems Engineering, 2012
The production of extracellular xylanase by a locally isolated strain of Aspergillus tubingensis JP-1 was studied under solid-state fermentation. Among the various agro residues used wheat straw was found to be the best for high yield of xylanase with poor cellulase production. The influence of various parameters such as initial pH, moisture, moistening agents, nitrogen sources, additives, surfactants and pretreatment of substrates were investigated. The production of the xylanase reached a peak in 8 days using untreated wheat straw with modified MS medium, pH 6.0 at 1:5 moisture level at 30°C. Under optimized conditions yield as high as 6,887 ± 16 U/g of untreated wheat straw was achieved. Crude xylanase was used for enzymatic saccharification of agro-residues like wheat straw, rice bran, wheat bran, sugarcane bagasse and industrial paper pulp. Dilute alkali (1 N NaOH) and acid (1 N H 2 SO 4) pretreatment were found to be beneficial for the efficient enzymatic hydrolysis of wheat straw. Dilute alkali and acid-pretreated wheat straw yielded 688 and 543 mg/g reducing sugar, respectively. Yield of 726 mg/g reducing sugar was obtained from paper pulp after 48 h of incubation.
Materials Today: Proceedings, 2016
A fungal strain (Aspergillus sp.S6) isolated from soil and identified as Aspergillus aculeatus was found to produce xylanase using SSF. The optimum conditions for enzymesubstrate reaction were pH : 4.8 , temperature : 60 o C, incubation time : 5 min, substrate concentration : 5mg/ml. Enzyme activity was stimulated by Ca 2+ , K + and Cu 2+ while completely inhibited by Hg 2+ and Ag +. Untreated moistened wheat bran at 25 o C subjected to 72 h fermentation using Aspergillus aculeatus provided maximum xylanase production (253.98IU/gds). Supplementation with xylan (1%) and ammonium chloride (0.5-1 %) improved enzyme production. Small catabolic repression occurred in xylose and glucose supplemented wheat bran.
Fountain Journal of Natural and Applied Sciences
Xylanases are hydrolytic enzymes with wide range of applications in food processing, bleaching of pulp in paper manufacturing industry, bio-conversion of biomass wastes to fermentable sugars and enhancing nutrient digestibility in animal feeds. The optimization of growth conditions and evaluation of an appropriate substrate as carbon source among cassava peels, corn cobs, wheat bran and rice husk on xylanase production by novel strain of Aspergillus tubingensis under Solid State Fermentation (SSF) was investigated. The fungal isolate was identified based on ribosomal RNA gene and ITS gene sequencing analysis as Aspergillus tubingensis. Results showed that Corn cobs had the highest xylanase production among the four substrates. Corn cobs recorded the highest value of xylanase production at pH of 6.0 (107.97 U/g), after incubation period of 72 hour (111.23 U/g), at temperature of 30oC (44.26 U/g) and at ratio 1:3 (45.68 U/g). The optimum growth conditions for xylanase production by As...
Optimization of Xylanase production from Aspergillus niger by Solid state fermentation.docx
Aspergillus niger is one of the most important filamentous fungi that used in the fermentation industry. Aspergillus niger isolate was cultured on potato-dextrose agar (PDA) for activation, and the optimum conditions for xylanase production from this local isolate were studied by solid state fermentation, using a medium composed of wheat bran moisten with corn steep liquor at ratio 1:0.5 (v:w) at initial pH 5.5, inoculated with 1.6 × 106 spores/ml, and incubated at 30Cᵒ for 5 days.