L-色氨酸营养缺陷型高产菌株的发酵工艺研究

目的以L-色氨酸营养缺陷型高产菌HX22-118为出发菌株,研究探讨L-色氨酸补料分批发酵工艺。方法通过对L-色氨酸补料分批发酵工艺中不同初糖浓度、不同补料方式、碳氮源比例、不同p H值调节方式、添加L-苯丙氨酸、L-酪氨酸对发酵的影响进行了研究。结果通过补料分批发酵工艺能有效地解除了高糖对菌体生长的抑制,促进菌体生长产酸,选择初糖淀粉浓度为90 g/L,保持葡萄糖总浓度160 g/L,在发酵第24 h开始连续流加剩余的糖,并于发酵第12 h和24 h分2次补加各50 mg/L的L-苯丙氨酸、L-酪氨酸,同时用氨水与Na OH控制发酵过程的p H,发酵产酸较分批发酵的33.5 g/L提高49.5%,达到50.1 g/L,缩短了发酵周期,提高了原料利用率。结论形成一套先进的L-色氨酸工业化发酵生产工艺技术,产酸高,生产运行稳定。

Research on fermentation process with L-tryptophan auxotrophic strains of high-yield

Objective The batch fermentation of L-tryptophan filling material was researched by using L-tryptophan auxotroph high-yielding bacteria HX22-118 as a starting strain. Methods The different initial sugar concentration, different ways of filling material, different proportion of carbon and nitrogen sources, dif-ferent pH adjustment methods, as well as the adding of L-phenylalanine and L-tyrosine, on fermentation with L-tryptophan as filling material were studied. Results By covering material batch fermentation process could effectively remove the sugar on inhibition of bacteria growth, and promote the growth of bacteria to produce acid. The concentration of sugar starch was 90 g/L, the total concentration of glucose was 160 g/L, after a 24 h fermentation there began the continuous flow with the rest of the sugar, and in the 12 h fermentation and 24 h fermentation points each 50 mg/L of L-phenylalanine and L-tyrosine was added 2 times, and at the same time with ammonia and NaOH were added to control the pH. The fermentation promoted the acid fermentation to produce the batch fermentation of 33.5 g/L, which was increased by 49.5% to 50.1 g/L, shortening the fermentation period, and improving the utilization rate of raw materials. Conclusion The advanced industrial fermentation of L-tryptophan production technology was formed, which could produce acid quite high, with a stable production operation.