ENHANCED PRODUCTION OF LIGNOCELLULOLYTIC ENZYMES BY BACTERIAL CULTURE OF DELFTIA SP. THROUGH SUBMERGED STATE FERMENTATION OF BIODIGESTED SLURRY AND UTILIZATION FOR BIOGAS AUGMENTATION USING PADDY STRAW

The bioconversion of various agricultural residues can be used to produce biofuels, biological products and biogas augmentation. The objective of this study was to produce lignocellulolytic enzymes by Delftia sp. PP4_S3 using biodigested slurry and their utilization for degradation of paddy straw for biogas augmentation. Delftia sp. PP4_S3 in biodigested slurry produced exoglucanase activity of 0.036 U mL(-1), beta-glucosidase activity of 1.459 U mL(-1), manganese peroxidase activity of 0.244 U mL(-1) and lignin peroxidase activity of 0.111 U mL(-1). RSM mediated optimization gave maximum enzyme activities at 50% slurry concentration, 1% inoculum and incubation period of 5 days. After upscaled submerged state fermentation, the paddy straw supplemented with enzyme enriched biodigested slurry showed 35% increase in biogas production, as compared to the control. A decrease in cellulose, hemicelloses and lignin percentage, with an increase in ash and silica percentage, was reported. Thus, Delftia proved to be an excellent source for lignocellulolytic enzyme production using biodigested slurry waste and subsequent biogas augmentation.