ANTAGONISTIC CHARACTERIZATION OF MARINE MICROALGAE EPIPHYTIC BACTERIUM PSEUDOMONAS MALTOPHILIA SU2 AGAINST SELECTED CLINICAL PATHOGENS

Abstract

Marine epiphytic bacteria become an important array of study in the exploration for novel microbial products. In recent years pharmaceutical, industrial focus on screening of marine microorganisms for biologically active secondary metabolites. We have studied antagonistic epiphytic bacteria from marine microalgae Tetraselmis suecica (Kylin). The antagonistic screening was carried out against selected clinical pathogens by the isolates. The potential epiphytic bacterium was identified as Pseudomonas maltophilia SU2 and its antagonistic ability was assessed at different physico-chemical parameters. Among the pathogens tested, highest antibacterial activity was noticed against Vibrio cholera (18mm) when the isolate incubated at 35oC at the pH 9. The crude ethyl acetate extract was partially purified by column chromatography. Each fraction was subjected to perform thin layer chromatography to check the purity and to calculate the retention factors (Rf). The Rf value of fraction 1, 2 and 3 were 0.70, 67 and 0.58 respectively. All the fractions were subjected to antibacterial screening against selected human pathogens. A total of six fractions was tested, interestingly fraction 1&2 showed maximum activity (10 ± 0.70 mm) against Staphylococcus aureus and Streptococcus pyogenes. The crude compounds were identified using GC-MS analysis. The extract from this epiphytic bacteria contain an unusual chemical compound of 2, 6, 10, 14 Tetramethyl heptadecane with the molecular weight of 296.57. This finding indicates that marine epiphytic bacteria have a wide array of biosynthetic capabilities for the production of novel and unique structures for clinical applications.