Evaluating Bacterial Isolates for Enhanced Composting Efficiency: A Comparative Study of Mushroom Compost, Vermicompost and Earthworm Gut Bacteria

Background: Composting and vermicomposting are sustainable methods of organic waste management, which are catalyzed by complex microbial communities. Microbiota in the compost and earthworm’s gut play an important role in nutrient cycling and decomposition, but the relative ability of these microbial communities to stimulate composting efficiency has not been studied vastly. The present research cultured bacterial isolates of mushroom compost, vermicompost and earthworm gut and evaluated their biochemical properties, plant-growth-promoting abilities and enzyme degrading potential. Methods: Bacterial cultures were isolated from mushroom compost, earthworm gut and vermicompost collected from different composting units at Dr. Rajendra Prasad Central Agricultural University, Pusa. The distinct morphological colonies formed on various agar plates were tested for Gram staining. The isolates were screened for cellulose and hemicellulose degradation and the ability to solubilize phosphorus, potassium and zinc, production of siderophores were further biochemically characterised using IMViC test. The data was analyzed by using Origin Pro 2023b, version 10.0.5.157. Result: A total of 80 isolates were obtained by culturing on different media: 20 from mushroom compost, 40 from vermicompost and 20 from earthworm gut. The isolates obtained in mushroom compost had the highest cellulose and hemicellulose degradation index, the earthworm gut isolates had the highest phosphorus and zinc solubilization index and vermicompost isolates produced the highest siderophore. Thirty-one promising isolates, demonstrating multiple degradation and solubilization activities, were further characterized through IMViC tests and substantial diversity was observed. These bacterial isolates hold potential for enhancing composting efficiency, promoting faster decomposition and nutrient release.