RESUMEN
Deep Sea sediment cores were collected from the surrounding of active volcanic Barren Island, Andaman & Nicobar Islands. A total of 24â¯halophilic eubacteria were isolated and identified based on their biochemical and 16S rDNA sequences. Three major classes (Gamma-Proteobacteria, Alpha-Proteobacteria and Bacilli) of bacteria were detected in the deep sea sediments of active volcanic Barren Island. Among those, 37% of isolates exhibited antimicrobial activity against all tested Gram positive and Gram negative clinical pathogens. 60% of isolates revealed the presence of either PKS or NRPS genes and 65% isolates disclosed medium to higher level of cytotoxicity in MB-231 breast cancer cell line. Majority of the isolates revealed excellent potential for bioprospecting of novel byproducts with industrial and pharmaceutical importance.
Asunto(s)
Bacterias , Ecosistema , Microbiología del Agua , Bacterias/clasificación , Bacterias/aislamiento & purificación , Sedimentos Geológicos/microbiología , Islas , Océanos y Mares , Filogenia , ARN Ribosómico 16S/genéticaRESUMEN
The production of a lipopeptide surfactant from the sponge-associated eubacteria Bacillus licheniformis NIOT-AMKV06 from the Andaman and Nicobar Islands was investigated. The highest production was attained with glucose and yeast extracts as the carbon and nitrogen sources (1.789 mg mL(-1)), respectively. The surfactant was highly stable over a pH range of 5.0-10 and a temperature range of 20-70°C with high NaCl concentrations. Excellent emulsification activity was exhibited by the purified surfactant with crude oil, kerosene, and diesel. A two-fold increase in surfactant production (3.0 mg mL(-1)) was observed using the newly formulated medium in this study. The surfactant biosynthesis gene cluster (sfp, sfpO, and srfA) from B. licheniformis NIOT-AMKV06 was heterologously expressed in Escherichia coli, and the production was increased three-fold (11.78 g L(-1)) over the original strain. The results confirm the potential of the surfactant for use in bioremediation of hydrocarbons in a marine environment and for enhanced oil recovery. To our knowledge, this is the first report on the ability of a hydrocarbon degrading B. licheniformis from marine sponges for the biosynthesis of a potent lipopeptide surfactant possessing characteristics of maximum stability, outstanding surfactant activity, and exceptional emulsifying capability.