摘要
在10L发酵罐培养地中海拟无枝酸菌过程中基料添加Zn2+(终浓度0.75mg/L)对利福霉素SV效价和有机酸合成产生了显著影响。72h^141h胞外丙酮酸、丙氨酸浓度分别比对照提高了19.7%~93.72%和降低了37.69%~59.55%;同时,胞外谷氨酸、赖氨酸和苯丙氨酸的浓度分别比对照提高了7.62%~162.59%、1.99%~43.10%和25.84%~92.89%。胞外酪氨酸浓度(72h^120h)与对照差异不大,之后迅速提高,141h时酪氨酸浓度是对照组的2.56倍。利福霉素SV的效价在96h比对照提高了11.72%,120h时效价提高了9.1%;141h时效价仅比对照提高了3.5%。说明锌离子抑制了丙氨酸脱氢酶活性并引起丙酮酸积累,这使得丙酮酸流入三羧酸循环的碳通量增大,使由草酰乙酸衍生的赖氨酸和由α-酮戊二酸衍生的谷氨酸合成量增大,促进了利福霉素SV的合成。但是,丙酮酸的积累也促进了芳环氨基酸的合成(如酪氨酸、苯丙氨酸),其会协同抑制利福霉素的芳环前体3-氨基-5-羟基-苯甲酸的合成,这可能是效价中后期增长放缓的原因。
The effects of Zn2＋ addition on organic acids and rifamycin SV productions by Amycolatoposis mediterranei in a 10L bioreactor were inves- tigated. Compared with the control, the extracellular pyruvate content was increased by 19.7%-93.72% corresponding to 49.98mg/L-85.63mg/L and that of Ala was decreased by 37.69%-59.55% corresponding to 3.97mg/L-18.33mg/L from 72h to 141h. Meanwhile, the extracellular Glu, Lys and Phe content was 12.59mg/L -948.12mg/L, 20.97mg/L-26.23mg/L and 1.64mg/L-11.13mg/L, respectively, which was increased by 7.62%- 162.59%, 1.99%-43.10% and 25.84%-92.89% relative to the control, respectively. The extracellular Tyr content was enhanced quickly from 120h to 141h, and was 1.65mg/L at 141h, which was 2.56 times that of the control. The rifamycin SV production at 96h was 3173U/ml that was increased by 11.72% relative to the control, however, that at 120h and 141h was 9.1% and 3.5%, respectively. The results suggested that Zn2＋ addition inhibited the Ala dehydrogenase activity, facilitated pyruvate accumulation, favored the carbon flux into citrate cycle, enhance the syntheses of Lys and Glu, thus the increase in rifamycin SV production was observed. However, Zn2＋ addition also supported the syntheses of Tyr and Phe, which inhibited the 3-amino-5-hydroxybenzoic acid synthesis synergistically, which would be the reason why the slowdown of rifamycin SV production from 120h to 141 h relative to the control.
出处
《中国酿造》
CAS
2013年第8期84-87,共4页
China Brewing
基金
河南省南街村(集团)有限公司科技攻关项目(20110388)
