Isolation and identification of thermophilic cellulolytic bacterium Streptomyces thermocarboxydus and its degradation effect on moso bamboo waste

Significant waste is generated during the processing of Moso bamboo (Phyllostachys edulis). High-temperature aerobic composting offers an effective method for utilizing Moso bamboo waste, with cellulose degradation being crucial to improving compost quality and efficiency. Isolation and screening of thermophilic cellulose-decomposing bacteria is vital for enhancing bamboo waste composting. In this study, samples were collected from lignocellulose-rich environments such as soils from rice fields, grasslands, bamboo forests, forest, and high-temperature straw compost sites in Hunan. Bacteria were enriched at 50℃ using cellulose from bamboo processing residues as the sole carbon source and screened using the hydrolysis ring method. Strains were evaluated for Moso bamboo weight loss, carboxymethyl cellulase (CMCase) activity, and filter paper cellulase (FPase) activity to identify those with superior degradation performance. The isolates, primarily fungi and actinomycetes, were further analyzed for temperature-dependent degradation and lignocellulose breakdown. The strain JFDF-S1 showed the highest weight loss rate (20.35%) after 5 days of liquid fermentation at 50℃, along with significantly higher CMCase and FPase activities. Identified as Streptomyces thermocarboxydus based on colony morphology and molecular biology, JFDF-S1 demonstrated robust growth and degradation capacity between 30–55℃ aligning well composting process. It effectively decomposes hemicellulose and cellulose components in bamboo waste. This study provides a theoretical basis for the development of microbial agents to enhance bamboo composting efficiency, support bamboo waste recycling, and foster sustainable development of the bamboo industry.