Utilization of anaerobically treated distillery spent wash for production of cellulases under solid-state fermentation

Abstract

Pollution caused by distillery spent wash on one hand has stimulated the need to develop new technologies to treat the waste and on the other, forced us to reevaluate the efficient utilization of its nutritive potential for production of various high value compounds. In this study, anaerobically treated distillery spent wash was used for the production of cellulases by Aspergillus ellipticus under solid-state fermentation using wheat straw as a substrate. The interactions between distillery effluent concentration, initial pH, moisture content and inoculum size were investigated and modeled using response surface methodology (RSM) involving Box–Behnken design (BBD). Under optimized conditions, filter paper activity, β-glucosidase and endo-β-1,4-glucanase activities were found to be 13.38, 26.68 and 130.92 U/g of substrate respectively. Characterization of endo-β-1,4-glucanase and β-glucosidase was done after partial purification by ammonium sulfate fractionation followed by desalting. The partially purified endo-β-1,4-glucanase and β-glucosidase showed maximum activity at 60 °C. Saccharification studies performed with different lignocellulosic substrates showed that wheat bran was most susceptible to enzymatic hydrolysis. The study suggests that anaerobically treated distillery spent wash can be used as a viable nutrient source for cellulase production under solid-state fermentation by A. ellipticus.