Optimum of medium components for the production of ectoine by a halophilic bacterium isolated from Can Gio mangrove

Abstract

A fermentation process for ectoine production has been developed, using a halophilic bacterium strain D209 isolated from Can Gio mangrove as the producer strain. First, the effect of different carbon and nitrogen sources on growth of producer strain was investigated. Sucrose and glucose were found to be suitable carbon sources, and monosodium glutamate was favorable nitrogen source for bacterial cell growth. The effect of different NaCl concentrations on growth and ectoine accumulation was also evaluated. Optimum salt concentrations for bacterial growth was ranged from 4 to 6 %, whereas, NaCl concentrations from 12 to 15 % found to be good for ectoine accumulation. Two-step fed-batch fermentation was then designed, first step for biomass production and second step for ectoine synthesis. Biomass and ectoine content were significant increased by using this process, maximum CDW of 25 g/l and ectoine content of 10.3 % were obtained. Strain D209 was then characterized by using 16S rRNA gene sequence. Our results showed that strain D209 belonged to Halomonas genus and closed to Halomonas organivorans species.