A comparative study was done for feasibility of pulse husk waste (Green gram husk (GgH), Black gram husk (BgH), Bengal gram husk (BegH) and Red gram husk (RgH)) as substrates for laccase production by Pleurotus ostreatus 1804 under solid state fermentation. Various process parameters like incubation time, pH of the culture, initial moisture content, particle size, inoculum size, substrate loading, and effect of inducer (2,5-xylidene) on laccase production were investigated. To characterize the solid substrate (pulse husks) before and after fermentation FT-IR, substrate components (cellulose, total carbohydrates, and lignin) and CHNS analysis were done. Inducer enhanced 2-fold of the laccase yield at optimized culture conditions. GgH was proven to be the best source for laccase production with maximum yield of 2200 U compared to all other substrate studied [1350 U (BgH), 1010 U (BegH) and 810U (RgH)].
Keywords: Laccase, Pleurotus ostreatus, solid state fermentation, optimization, husk.