Role of lignocellulolytic thermophilic fungus Thermoascus aurantiacus MTCC 375 in paddy straw digestibility and its implication in biogas production

Abstract

Paddy straw was pretreated with Thermoascus aurantiacus MTCC 375, a ligno-cellulolytic thermophilic fungus, to enhance its biodegradability. The potential of microbial pretreatment under aerobic condition on paddy straw digestibility was investigated at regular intervals of 1, 2, 3, 4 and 5 days by determining the change in proximate (total solids (%) and volatile solids (%)) and chemical composition (cellulose, hemicellulose, lignin and silica content). The pretreatment of 5 days significantly (P ≤ 0.05) reduced the concentrations of cellulose, hemicelluloses, lignin and silica content in the paddy straw by 34.25, 39.19, 34.12 and 10.59%, respectively. A maximum of 30% increase in biogas production was observed from one day pretreated paddy straw as compared to untreated paddy straw. However, biogas production from paddy straw supplemented with enzyme containing digested biogas slurry without giving aerobic treatment was found to be more than the samples given aerobic treatment. In both cases, biogas production was greater than the control by 63.2 and 30.7%, respectively.   Key words: Paddy straw, pretreatment, lignin, Thermoascus aurantiacus, biodegradability, enzyme containing digested biogas slurry, biogas production