Biological Activities of Bacterial Isolates from Adiangao Cave, San Jose Camarines Sur

Abstract ―​

Considered an extreme environment, caves possessed a unique and poorly studied ecosystem comprising a unique microbial community carrying out various biological activities. This study aimed to isolate, identify, and characterize the biological activities of bacteria isolated from soil samples in Adiangao Cave, San Jose, Camarines Sur. Seventeen bacterial isolates were identified and characterized in terms of enzymatic activity, phosphate solubilizing activity, formaldehyde resistance, and antagonistic activity. Based on 16S rDNA sequencing, the most prevalent isolates obtained were members of the Bacillus genera. Results have shown that 11 isolates exhibited amylase activity, and 12 had cellulase activity, showing its potential for industrial application. Eight isolates were positive for phosphate solubilization, which can be used for plant growth promotion and heavy metal immobilization. It was also shown that 13 isolates could grow under the presence of formaldehyde showing its potential application for the bioremediation of formaldehyde. Isolate CS31, identified as Bacillus paranthracis, is noted to have great potential for the production of antimicrobial compounds that can inhibit pathogenic microorganisms such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Salmonella typhimurium. The results of this study demonstrated the importance of cave bacteria for the production of valuable bioactive compounds that are commercially important.