Year: 2013 | Month: June | Volume 3 | Issue 1
Brewer’s Spent Grain as a Valuable Substrate for Low Cost Production of Fungal Cellulases by Statistical Modeling in Solid State Fermentation and Generation of Cellulosic Ethanol
Abstract: <div>Brewer’s spent grain (BSG), a brewery waste was used as a substrate for cellulase production employing a laboratory isolate of Aspergillus sp.SS-25 under solid state fermentation as well as for cellulosic ethanol production. The cultural parameters and media components were statistically optimized for enhancing the cellulase yields employing Plackett-Burman design model. A near-optimum medium formulation for maximum cellulase production by the fungus was determined that increased the CMCase, FPase and β-glucosidase yields by 3.1, 3.6 and 2.1 folds, respectively. Predicted results showed that supplementing malt spent grain with 20% (w/w) wheat bran, 2% each of potato peels, peptone, soyabean meal, tryptone, malt extract, 0.14% NH<sub>4</sub>SO<sub>4</sub>, 0.002% CoCl<sub>2</sub>, 0.0006% FeSO4, 0.1% MnCl<sub>2</sub>, 0.1% NaNO<sub>3</sub>, 0.03% urea, 0.03% NH<sub>4</sub>Cl, maintaining 70% moisture content and incubation at 30<sup>o</sup>C for 6 days induced maximum production of all the components of cellulase system yielding 295, 90 and 80 IU/g respectively for CMCase, FPase and β-glucosidase against the predicted yields of 289,</div><div>94 and 82 IU/g dry solids. The enzyme preparation worked well in degrading the cellulose fraction in steam pretreated BSG into glucose revealing 75% cellulose conversion efficiency by way of yielding 134 mg glucose/g of BSG. The fermentation efficiency of glucose was found to be 91% producing 78µl</div><div>ethanol/g of BSG.</div>
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