Isolation and characterization of an ectoine-producing moderate halophilic bacterium TA-4

A moderately halophilic bacterium TA-4 was isolated from a Tong-an saltern.The strain TA-4 was identified as Halomonas salina characterized by its 16S rDNA,morphology,physiological and biochemical properties.This strain was capable of growing in 2%～25% NaCl solutions,and exhibited an optimum growth in NaCl concentration of 6%,temperature at 35℃ and pH of 7.0～8.0,respectively.Under hyperosmotic stress,TA-4 accumulated ectoine as its main compatible solute which could reach to 60.3mg/g·cdw in the LB medium containing 15%NaCl.The osmotic tests indicated that the concentration of ectoine correlated linearly with medium osmolarity and the intracellular ectoine was immediately released outwards under hyperosmotic shock and can return to the original concentration by more than 90% in 6 hours after hyperosmotic shock.