Efficient Preparation Of Ectoine And Its Effection On Adversity Resistance And Assist Roles To Enzvmes/Cells

Compatible solute in moderately halophilic bacteria cells is an important mechanism of salt-tolerant. Ectoine is a usual compatible solute in moderately halophilic bacteria. Ectoine is not only able to balance the osmotic pressure, but also protect enzyme, DNA, membranes and whole cells against the extreme environments of high temperature, freeze, dryness, extreme PH value, high-pressure, high salt and high radiation, which had been applied in cosmeties, biological preparations and pharmaceutical industry, and other fields.Because of Ectoine contains a chiral carbon atom, it is difficult to synthesis with chemical methods. The technology of Ectoine preparation with microbial fermentation had increasingly attracted attention. The studies of the Ectoine preparation efficiency are mainly concentrated in the screening of strains and preparation process. On the majority of reports, there are some contradiction between the Ectoine intracellular threshold and high salt concentration. Using bacterial milking technique for preparation of Ectoine, the production of Ectoine were greatly improved, but the Ectoine release rate is not high. The fermentation technology level of Ectoine is not high, especially the fermentation process is short of the optimization control theoryIn order to solve the above problem, Halomonas venusta DSM4743which could resist to higher halostress of NaCl concentration and synthesize higher intracellular Ectoine concentration was adopted. The maximum Ectoine concentration was3.2g/L with the batch fermentation processe at1.5mol/L NaCl. H. venusta DSM4743was able to tolerate the osmotic shock. Ectoine was produced by "bacterial milking". The total concentration of synthesized Ectoine was14.7g/L. The average release rate of Ectoine was97%. At the same time, according to the metabolic flux analysis, the fermentation process of H. venusta DSM4743was realized the optimization control. Ectoine concentration was increased in Ectoine fermentation adopting monosodium glutamate as the sole carbon and nitrogen sources, feeding monosodium glutamate and supplying oxygen limitedly. The concentration and yield of Ectoine were increased by2.8and2times, respectively by comparison with batch fermentation using glucose as carbon source. In the applied research of Ectoine. the mylase.(3-glucanase and cellulose of malt was selected. In the preparation process of malt, the activities of amylase, β-glucanase and cellulose had different degree loss at high temperatures. It is resulted to decreas the brewing performance of malt. In this paper, the effects of the addition of Ectoine on the adversity resistance and assist roles of enzymes were studied at the high temperatures.The results showed that after heat treatment at80℃and at90℃, the addition of Ectoine could improve the residual amylase activities by17.6%and by26.8%respectively (compared with that without Ectoine addition), the addition of Ectoine could improve the residual β-glucanase activities by25.7%and by34.6%respectively, and the addition of Ectoine could improve the residual cellulase activities by57.6%and by50.8%respectively. In the enzyme’s heat treatment system, the effect of Ectoine on the adversity resistance and assist roles of enzymes was remarkable.