Role of Compatible Solutes in the Fast Growth Bacterium Salinivibrio costicola subsp. yaniae

Salinivibrio costicola subsp. yaniae (NCCB 100212) is a moderately halophilic bacterium which has recently been isolated in a saltern located on the coast of Yellow Sea of North China. S. costicola subsp. yaniae, which is termed as strain DL6, has a short generation time, i.e., doubling time was 11.4 min during 2.5-5.5 h of incubation. Glycine betaine, ectoine, and glutamate were identified as the predominant compatible solutes by ¹³ C-NMR analyses when strain DL6 was grown in the nutrient AS medium. Glycine betaine might be taken up or converted from choline rather than de novo synthesis, while ectoine was synthesized de novo. Under low salinity condition, on the other hand, glycine betaine has no effect on the growth of strain DL6, but it will improve the level of cells to cope with osmotic stress at high salinity. Glutamate did not support the cell survival for high osmotic stress. Therefore, strain DL6 developed and constructed such complex system to adapt itself against high salinity environments.