Diversity of Cellulolytic Bacteria Isolated from Goat Feces in Rayong Province, Eastern Thailand, and Characterization of Their Endoglucanase Activity

Bacterial cellulases are crucial for breaking down cellulose, which is essential for various industries. These bacteria are found in the rumen of herbivores including domestic goats. Goat feces show potential as a source of cellulase-producing bacteria, but studies on these bacteria isolated from goat feces in Thailand remain limited. This study isolated and genetically identified cellulase-producing bacteria from goat feces in eastern Thailand. The cellulases produced by the most effective cellulase-producing bacterium were also characterized enzymatically. A total of 30 cellulase-producing bacteria were isolated and classified using PCR-RFLP analysis of the 16S rRNA gene. Thirteen different RFLP patterns were obtained through MspI-AluI digestion, belonging to nine bacterial genera: Acinetobacter, Bacillus, Corynebacterium, Enterococcus, Escherichia, Exiguobacterium, Providencia, Pseudomonas, and Staphylococcus (Mammaliicoccus). The predominant genera of the isolated cellulase-producing bacteria were Escherichia, Exiguobacterium, and Corynebacterium. Several of the isolated bacterial species had limited prior evidence of cellulase production. Bacillus sp. strain FMJ 1105 showed the highest cellulase activity using the CMC agar method and produced CMCase (endoglucanase) activity of 2.67 ± 0.06 U/mL. The optimum temperature and pH for CMCase activity were determined to be 50°C and pH 7.0, with a stability range of 25-70°C and pH 6.0-8.0 over 24 h of incubation. This study provides new insights into cellulase-producing bacteria isolated from goat feces in Thailand, contributing to the understanding of their enzymatic potential.