Antimicrobial Activity of Lichens-Associated Actinomycetes Strain LC-23

Actinomycetes known as the largest antibiotic producer that has a broad range habitat. Research has been done to find a new antibiotic from the various habitats of actinomycetes. Lichens was the symbiotic structure of alga and fungi known as the ecological niche of various kinds of microbes including actinomycetes. The aim of this study in deep of isolate strain LC-23 for production of antimicrobial, characterize the metabolite profile of the ethyl acetate extract and identification based on 16S rRNA gene sequence analysis. The result revealed actinomycetes from lichen, strain LC-23 showed potency against Gram positive bacteria. Ethyl acetate extract of the strain showed positive inhibition against Staphylococcus aureus BTCC B-611 and Micrococcus luteus BTCC B-552. Minimum Inhibitory Concentration (MIC) of extract LC-23 was less than 2.106 ppm. The ethyl acetate extract was subjected to fractionation and tested against the pathogenic microbes and showed inhibition activity in column 9 and 10, and specifically in column 7E to 7G for Staphylcoccus aureus BTCC B-611 and 7E-7H for Micrococcus luteus BTCC B-552. The identification based on 16S rRNA gene sequence showed strain LC-23 was 98.51% similarity to Streptomyces palmae type strain. Neighbor-joining phylogenetic tree confirmed the relationships of this strain to other members of Streptomyces genera.