Utilization of Jatropha deoiled seed cake for production of cellulases under solid-state fermentation

Abstract

Toxic waste generated by Jatropha seed cake after utilization of biodiesel 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 and its conversion to non-toxic forms which could be used as animal feed stock. In this study, Jatropha seed cake was used for production of cellulases by new isolate of Thermoascus aurantiacus under solid-state fermentation. The interaction of nitrogen source concentration, moisture ratio, initial pH of the medium and inoculum size was investigated and modelled using response surface methodology (RSM) using Box-Behnken Design (BBD). Under optimized conditions endo-β-1,4-glucanase, β-glucosidase and filter paper activities were found to be 124.44, 28.86, 4.87U/g of substrate, respectively. Characterization of endo-β-1,4-glucanase, β-glucosidase was done after partial purification by ammonium sulfate fractionation followed by desalting. The endo-β-1,4-glucanase and β-glucosidase showed maximum activity at 70°C and pH 4. Saccharification studies performed with different lignocellulosic substrates showed that sugar cane bagasse was most susceptible to enzymatic hydrolysis. The study suggests that Jatropha seed cake can be used as a viable nutrient source for cellulase production without any pretreatment under solid-state fermentation by T. aurantiacus.