Isolation, Screening and Characterization of Cellulolytic Fungi from Decaying Plant Materials for Sustainable Bioethanol Production

Abstract

The increasing generation of plant waste presents significant environmental and public health challenges while simultaneously offering an abundant renewable resource for biofuel production. Microbial cellulases play a pivotal role in the conversion of lignocellulosic biomass into fermentable sugars, making the isolation of efficient cellulolytic fungi essential for sustainable bioethanol production. This study investigated the occurrence, isolation, screening, and characterization of cellulolytic fungi from decaying plant debris with the aim of identifying promising cellulase-producing strains for bioethanol production. Decaying plant debris samples were collected from domestic sources, processed under aseptic conditions, and cultured using standard microbiological techniques. Distinct fungal isolates were purified and identified based on their morphological and cultural characteristics. Preliminary screening for cellulase production was carried out on carboxymethyl cellulose (CMC) agar using Congo red staining, followed by quantitative determination of cellulase activity using standard enzyme assays. The cellulolytic potential of the isolates was evaluated by measuring hydrolysis zones and enzyme activity under controlled laboratory conditions. Selected isolates exhibiting superior cellulolytic activity were further characterized for their suitability in lignocellulosic biomass degradation. The findings demonstrated considerable diversity among the isolated microorganisms, with several fungal species exhibiting significant cellulolytic capabilities. The best-performing isolates producing large hydrolysis zones and high cellulase activities were Phanerochaete concrescens and Fusarium solani, producing 12.5 and 2.6 µmol/min/mg respectively indicating their potential application in enzymatic saccharification of decaying plant material. These findings provide valuable insights into the utilization of locally available microbial resources for sustainable waste valorization and renewable energy generation.