Diversity of Myxobacteria Isolated from Indonesian Mangroves and Their Potential for New Antimicrobial Sources

Mangroves are unique intertidal ecosystems that provide ecological niches to different microbes, which play various roles in nutrient recycling and diverse environmental activities. The association between myxobacteria and mangroves are hitherto poorly understood. The aim of our study was to evaluate the myxobacterial community composition as well as isolate myxobacteria and to characterize the antimicrobial activity of myxobacteria isolates from Indonesian mangroves. Twenty-five cultivable myxobacteria were affiliated in six genera: Myxococcus, Corallococcus, Archangium, Chondromyces, Racemicystis and Nannocystis of the order Myxococcales based on partial 16S rRNA gene sequences. Thirteen crude extracts showed moderate activities against at least one of human pathogenic microorganisms. The crude extract of Racemicystis sp. strain 503MSO indicated a novel compound, which has not been reported in the database yet and the identification of this compound needs further study. The myxobacterial communities of three different sampling sites were analyzed using primers adapted for the myxobacteria group identification. The results showed that myxobacterial communities are more diverse than assumed. Therefore, our study has highlighted the importance of the mangrove habitat as promising harbor of myxobacteria as well as novel antimicrobial compounds with activity against pathogenic microorganisms.