假单胞菌F12中氨对产酶及L-半胱氨酸合成的影响

Effect of ammonium on enzyme production and L-cysteine biosynthesis in Pseudomonas sp. F12

目的:探索假单胞菌F12氨的代谢及积累对产酶和转化合成L-半胱氨酸的影响。方法:本研究考察了氨对菌体生长、对DL-2-氨基-△2-噻唑啉-4-羧酸(DL-ATC)的代谢及产酶的影响,以及转化过程中氨的积累对L-半胱氨酸合成的影响。结果:氨浓度大于60mmol/L时对菌体生长有明显抑制作用,并没有影响DL-ATC的代谢和产酶,但同时加入葡萄糖后产酶显著下降;转化过程中有氨的释放,但DL-ATC消耗引起的氨的积累不影响L-半胱氨酸的合成。结论:氨的积累在产酶阶段和转化阶段对L-半胱氨酸的合成影响不显著。

Objective .. To figure out the metabolic characterastics of ammonium in Pseudomonas sp. F12 and the the effect of ammonium accumulation on enzyme production and L-cysteine synthesis. Methods .. The effect of ammonium on growth,DL-ATC consumption and enzyme production were performed. Besides,the effect of ammonium on bioconversion was also investigated. Results.Ammonium concentration higher than 60mmol/L inhibited growth but did not exert negative effect on DL-ATC metabolism and enzyme production. However, both ammonium and glucose existed in medium greatly decreased enzyme production. The accumulation of ammonium in bioconversion did not exert negtive effect on L-cysteine synthesis. Conclusion..the accumulation of ammonium released from DL-ATC utilization or bioconversion did not exert negative effect in enzyme production and L-cysteine synthesis.