Selective Isolation of Actinomycetes from Mangrove Forest of Pahang, Malaysia

Abstract

Actinomycetes which abundantly found in nature are renowned for their unique capabilities to produce biologically active metabolites. Poorly studied mangrove ecosystem offers a promising natural resource of new actinomycetes due to their high species diversity. This study aims to assess the diversity of actinomycetes from mangrove forest of Pahang, Malaysia. Various selective isolation media and pre-treatments were employed for maximum isolation of mangrove actinomycetes. A total of 4850 actinomycete isolates had been successfully recovered. It was observed that inorganic-salt starch agar (ISP4) displayed the highest percentage of actinomycetes recovery (31.7 %). Starch-yeast extract (SYE) and starch casein agar (SCA) were found to be more efficient in isolating wide variety of actinomycetes based on their morphological appearance. It was also observed that wet heat pre-treatment was more effective in isolating mangrove actinomycetes as 81.4 % of total isolates were yielded using this technique. On the other hand, dry heat treatment was better in the enumeration of spore-forming actinomycetes despite lower number of isolates recovered. Of both pre-treatments, station 1 which is located within the deep mangrove forest area recorded the highest recovery (23.7 %), with Streptomyces and Micromonospora-like isolates being the most predominant observed from all sampling sites. The presence of relatively large number of isolates suggests that Pahang mangrove forest is a potentially rich source of actinomycetes.