Aquatic Bacillus cereus JD0404 isolated from the muddy sediments of mangrove swamps in Thailand and characterization of its cellulolytic activity

This study aimed to conduct the isolation, screening and identification of bacteria with a high level of cellulolytic activity from the muddy sediments of mangrove swamps in Thailand. One hundred and ninety aquatic bacterial isolates were isolated from different muddy sediments and eighty one isolates were determined to be cellulolytic bacteria. The cellulolytic bacterium identified as Bacillus cereus JD0404 showed maximum hydrolysis activity on carboxymethylcellulose agar plates. Its cellulolytic performance for CMCase activity, Avicelase activity and β-glucosidase activity was 1.778 ± 0.003 U/mL, 0.079 ± 0.001 U/mL and 0.048 ± 0.002 U/mL, respectively. The optimum temperature and pH for the enzyme activity were determined to be 50 °C and 7.0 respectively. The cellulolytic activity was greatly enhanced by Mn2+ and considerably inhibited by EDTA and toluene. Preliminary bioconversion application showed that the B. cereus JD0404 could be used for the hydrolysis of cellulose-based biomass. This study demonstrated a feasible bacterium for environmentally friendly industries and biotechnology.