Unraveling the Efficient Cellulolytic and Lytic Polysaccharide Monooxygenases Producing Microbes from Paddy Soil for Efficient Cellulose Degradation

Abstract

Paddy straw, an abundant agricultural residue obtained from rice harvesting, poses significant environmental challenges due to its improper management and disposal practices, including the prevalent practice of residue burning. To address these issues, there is a growing need to explore sustainable alternatives for paddy straw decomposition. This study aims to harness the crucial role of microbes in facilitating the degradation of cellulose. The bacterial and fungal cultures were isolated and screened for cellulolytic enzyme activity. Among the microorganisms, fungi isolates showed significantly higher CMSase and FPase activity compared to bacterial isolates. Fungal isolates exhibiting superior enzymatic activities were subsequently identified using Internal Transcribed Spacer (ITS). Among the fungal isolates F-9: Aspergillus fumigatus and F-5: Trichoderma asperellum exhibited the highest carboxymethyl cellulase (CMCase) and filter paperase (FPase) activity with 40.14 and 68.02 U mL-1 respectively, when inoculated in a Reese’s mineral medium containing 1% microcrystalline cellulose. Through spectrophotometric analysis the highest LPMOs activity was recorded in F-8: Aspergillus aculeatus with 0.85 U mL-1 and F-3: Phanerodontia chrysosporium with 0.73 U mL-1. This study highlights the importance of fungi, particularly Aspergillus fumigatus, Trichoderma asperellum, and Aspergillus aculeatus in accelerating cellulose degradation through their robust cellulolytic and LPMO enzyme activities.