Synergistic microbial consortia for lignocellulose decomposition in paddy straw

This study investigates the enzymatic degradation of paddy straw (PS) by utilizing submerged state fermentation. Lignocellulolytic ability of six bacterial cultures (isolated from mushroom compost) and one standard culture of Delftia sp. PP4_S3 was evaluated as a consortium to degrade PS. Efficacy of cultures to breakdown lignocellulose was assessed qualitatively, whereby isolate B2 resulted in the highest potency index (PI) of 1.33 for cellulase activity, B6 for hemicellulolytic activity (1.68) and B4 for lignolytic activity (1.32). A synergistic micro-consortia of the isolated and standard culture was used to decompose PS resulting in maximum enzyme activities of endoglucanase (0.79 U/ml), exoglucanase (1.03 U/ml), β-glucosidase (1.59 U/ml), xylanase (11.83 U/ml) and manganese peroxidase (3.84 U/ml) after 21 days of incubation along with laccase (3.77 U/ml) and lignin peroxidase (6.12 U/ml) after 28 days of incubation. By the action of the consortium, PS exhibited a remarkable reduction of 33.51% in cellulose, 20.5% in hemicellulose and 42.72% in lignin content after 28 days of incubation. Structural damage in straw was proven from Field emission scanning electron microscope (FE-SEM). Consequently the use of microbial consortium for biodegradation of PS can be a promising approach to hasten degradation for in-situ management of paddy straw.