Construction Of Ectoine Synthesis Engineering Strain

Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) is a compatible solute synthesized by some microorganism to response to the stress of environmental osmotic pressure. Ectoine plays a stabilizing and protection function on living cells and other macromolecules, and it has the characteristic to balance osmotic pressure in extreme environments, so that there are broad prospects and development value in the field of environmental remediation, and the research of improving Ectoine synthesis efficiency has a great significance.Ectoine-specific transport protein (TeaABC) is discovered in Halomonas elongata DSM 2581T. H. elongata DSM 2581T regulates intracellular Ectoine synthesis and accumulation based the absorption of Ectoine by TeaABC and the release of Ectoine by the expansion pressure-sensitive channel. H. elongata DSM 2581T mutant, which is knockouted TeaABC coding gene teaABC, can only output Ectoine without absorption, blocked the balance of Ectoine output/absorption and compromised the negative feedback regulation of Ectoine synthesis, the synthesis of Ectoine increased more than intracellular concentration of Ectoine for balancing osmotic pressure. It means that the knockout of the only Ectoine transporter TeaABC led to a mutant of H. elongata can overproducing Ectoine.In this paper, we cloned Halomonas salina DSM 5928 teaABC gene by walking PCR, and knockouted it to construct Ectoine synthesis engineering strain of H. salina DSM 5928T by Red recombination technology. The Ectoine absorption experiments investigating the absorption efficiency of the strain. The total concentration of Ectoine and productivity in a 10 L fermentor were 9.10 (±0.08) g/L and 9.93 (±0.09) g/L.d, and build the fermentation kinetic model of the strain.