Adding value to agro-industrial waste for cellulase and xylanase production via solid-state bioconversion

The lignocellulosic biomass is presenting an enormous potential in biofuel production, which requires a hydrolyzing step in the bioconversion process. The biomass is hydrolyzed using costly enzymes like cellulase and xylanase. These enzymes can be produced by using lignocellulosic biomass as feedstock, and on-site produced crude enzyme can saccharify biomass. The integration of both approaches can lower down the cost of biofuel production. Keeping this in view, the present study was conducted to explore various agro-industrial waste as carbon sources and best-suited conditions for enhanced cellulase and xylanase production by Aspergillus flavus under solid-state fermentation. Among all studied biomass, microwave alkali-pretreated rice straw was found most suitable as a carbon source for enzyme production. Maximum enzyme activities FPase 12.5 IU/gds, CMCase 235 IU/gds, beta-glucosidase 190 IU/gds, and xylanase 180 IU/gds were obtained under optimum conditions of initial pH 5.5, temperature 30 degrees C, substrate to liquid ratio 1:3.5 (w/v), particle size 500-1000 mu m, and NaNO3 on the 5th day of the incubation period. Enzyme activities FPase, CMCase, beta-glucosidase, and xylanase were enhanced by approximately 1.27-, 1.18-, 1.06-, and 1.09-fold during tray fermentation. The adopted approach utilized low-cost lignocellulosic biomass for enzyme production as an additional avenue to biomass valorization along with solid waste management and its reduction which would otherwise cause environmental pollution problems.