Screening of secondary metabolite from waterfall and marine bacteria as biocontrol agent

Abstract

Biocontrol agent often used to reduce sources of disease, such as bacteria, fungi, and mosquito. Emergence of antibiotic-resistant bacteria and fungi are increasing due to excessive used of antimicrobial substances. Chemical substances used to kill mosquito larvae in water environment might also be dangerous for human and environment. Hence, a biocontrol agent is required to be safe and effective. The purpose of this study is to discover bacteria from waterfall and marine water which has a good potential as biocontrol agent. Four waterfall bacteria (S 1.1, S 2.1, S 3.1, and S 3.2) and three marine bacteria (A 1.1, A 1.2, and PA 1.3C) were proved to have antifungal activity towards pathogenic fungal. PA 1.3A was the only marine bacteria which proved to have antimicrobial activity towards Escherichia coli and Streptococcus agalactiae. Extraction of antimicrobial substance using several solvents resulted in larger clear zone diameter and inhibition of other bacteria, such as Bacillus licheniformis and Staphylococcus aureus. Extracted antimicrobial substance of PA 1.3A was also proved to be non toxic towards Aedes aegypti larvae through larvicidal assay and mammals through brine shrimp lethality assay (LC 50 > 1000µg/mL).