Exploration of Culturable Earthworm Gut Microbiota for Lignocellulolytic Enzyme Production in Organic Matter Decomposition

Composting is an effective and eco-friendly approach for reducing soil pollution caused by agricultural residues such as paddy and wheat straw, particularly under tropical climatic conditions. Eisenia fetida is a potent vermicomposting earthworm with immense agricultural importance due to its ability to facilitate decomposition and recycling of organic matter. In this context, a study has been conducted to evaluate the degradation potential of various enzymes derived from earth worm gut microbes in the decomposition of organic matter. A total of 31 microbial isolates were obtained from the earth worm gut, comprising 25 bacterial and 6 fungal cultures. These isolates were subjected to both qualitative and quantitative assessments for key enzymes, particularly cellulase, hemicellulase, and laccase. To identify the most efficient enzyme producing microbes, 16s rRNA sequencing was performed on selected high-performing isolates. Among the bacterial isolates, AJM22 (Bacillus cereus) showed highest cellulase activity (93.04 ± 0.24 U mL−1) while AJM9 (Paenibacillus dendritiformis) showed the highest xylanase activity (0.832 ± 0.02 U mL−1), among the fungal isolate AJF3 (Penicillium citrinum) recorded the highest activities of cellulase (124.84 ± 0.91 U mL−1), xylanase (1.146 ± 0.01 U mL−1) and laccase (9.34 ± 0.22 U mL−1). These microbes or their enzymes could potentially be used to enhance composting efficiency and enable more effective management of agricultural wastes.