Use of co-cultivation method to stimulate the production of antimicrobial natural products from mangrove microorganisms

Abstract

Discovery of novel antimicrobial bio-product is increasingly significant with rapid emergence of drug resistant pathogenic ‘superbugs’. Actinomycetes are high GC Gram-positive mycelial bacteria that are widely documented as a rich source of bioactive products, especially within the genus Streptomyces. Cryptic gene clusters from actinomycetes are suspected to harbor potential in producing bioactive products, and in this study, co-cultivation is utilized to stimulate these cryptic gene clusters in novel antibiotics production. 10 actinomycete strains isolated from Sungei Buloh Wetland Reserve were co-cultured with Mycobacterium Abscessus and Asperigillus Westerdijikiae in two liquid mediums, Glucose-Yeast extract-Malt extract (GYM) and Minimum Media (MM). Their culture extracts were screened for antibacterial activity using filter-disc assay. Experimental results indicated that co-cultivation with M. abscessus in GYM during Late Log Phase (LLP) of the actinomycetes’ growth led to an increase in antibacterial production. On the other hand, for co-cultivation in MM, more bioactive products were found when the co-cultivation with M. abscessus occurs during Early Phase (EP) of the actinomycetes’ growth. Potential candidates can be isolated and prioritized to undergo secondary screening using High Performance Layered Chromatography (HPLC) to further identify bioactive compounds present.