Isolation, Screening, and Identification of Efficient Lignocellulose-decomposing Microorganisms for Sustainable Agriculture

This study focuses on isolating and identifying bacterial and fungal decomposers with potential for environmentally sustainable crop residue management and soil fertility improvement. A total of 122 lignocellulolytic microorganisms (80 bacteria and 42 fungi) were isolated from crop residues, termite guts, and vermicompost. Among these, 18 promising isolates (12 bacterial and 6 fungal) were further characterized. Qualitative screening revealed strong cellulolytic activity in all isolates, evidenced by clear halo zones on CMC agar (Congo red staining). Notably, isolates CRDB34, CRDB42, and CRDF25 exhibited high β-glucosidase activity, while CRDF8, CRDF10, CRDB78, and CRDF25 showed significant xylanase and pectinase production. Quantitative assays demonstrated robust enzymatic potential: CMCase (15.2-137.0 IU/mL), FPase (8.6-129.8 IU/mL), and chitinase (4.7-21.7 IU/mL). Isolates CRDB52 (highest CMCase) and CRDF32 (highest xylanase, chitinase) emerged as top performers. Biochemical tests indicated diverse metabolic traits, including amylase activity, fermentation, catalase production, and ammonia generation, highlighting niche-specific adaptations. Notably, select isolates exhibited plant growth-promoting potential, with indole-3-acetic acid (IAA) production (up to 461.9 µg/mL) and phosphate solubilization (up to 600 µg/mL). Molecular identification confirmed Bacillus haynesii (CRDB-24), Bacillus altitudinis (CRDB48), Bacillus stratosphericus (CRDB52), Fusarium oxysporum (CRDF8), and Aspergillus fumigatus (CRDF32) as key decomposers, supported by 16S rRNA/ITS sequencing (92%-100% similarity). These isolates align with prior reports on lignocellulose. The study underscores the biotechnological potential of these isolates for sustainable residue management, offering enzymatic versatility and nutrient-mobilizing traits critical for agricultural applications.