Deoiled Rice Bran: A Substrate for Co-Production of a Consortium of Hydrolytic Enzymes by Aspergillus niger P-19

With the aim to utilize deoiled rice bran, an agro-industrial waste, as a feedstock for the co-production of multiple carbohydrases, a fungal strain was isolated which could utilize DORB to co-produce a consortium of cellulases, hemicellulases, pectinase and amylases and was named as Aspergillus niger P-19 after molecular identification. Further, optimization for the co-production of all the enzymes was carried out by one factor at a time approach. Time profile studies of the production of enzymes revealed that 5th day of incubation was best suited for the extraction of enzymes. An initial solid to moisture ratio of 1:1.5 and an inoculum size of 5 x 10(7) spores gds(-1) were found to be optimum for maximum productivities. Enzyme yields were significantly improved with the exogenous supplementation of carbon source, nitrogen source, surfactants and lignocellulosic inducers. This is the first report of its kind where DORB has been utilized for the co-production and co-optimization of eight different enzymes which can have a potential application in biofuel industry as the enzyme preparation could effectively hydrolyze steam pre-treated DORB releasing a total reducing sugars of 356.17 +/- 9.58 mg gds(-1).