Antimicrobial activity of Serratia sp isolated from the coralline red algae Amphiroa anceps

Abstract

Bacterial isolates (6 nos) were obtained from the coralline red algae Amphiroa anceps. Crude extract of these isolated were tested for antimicrobial activity against 20 different human pathogenic bacterial and fungal strains. Among this crude extract of a single red pigmented strain AA1 was found to show activity against (12) bacterial pathogens and (1) fungi. Higher range of antibacterial activity was observed against Staphylococcus aureus and antifungal activity against Rhizopus sp, while moderate antibacterial activity was observed with Salmonella typhi, Enteropathogenic E.coli and Klebsiella pneumonia. Identification based on morphological, biochemical and 16S rDNA sequencing showed that the strain AA1 was identified as Serratia sp (KC149511). Fractioned extract of the bacterial isolate was analyzed in a Gas Chromatography Mass Spectrometry (GC-MS). Results showed the presence of certain metabolites such as octadecanoic acid, phenol, 2, 4-bis (1, 1- dimethyl ethyl), nonanoic acid- 9 oxo methyl ester which could be responsible for the antifungal and antibacterial activities. Results showed that the pigmented Serratia sp is a potential source for bioactive substances and could contribute to the discovery of several novel compounds of pharmaceutical importance.