·132
2018 Vol.37 No.4 Serial No.314
China Brewing
Innovation and Knowledge Transfer
稀糖分罐发酵对L-色氨酸发酵的影响
刘子强张震蔡萌萌户红通陈宁徐庆阳*
（天津科技大学生物工程学院代谢控制发酵技术国家地方联合工程实验室天津市氨基酸高效绿色制造工程实验室，
天津300457
摘要为了解决现有L-色氨酸发酵工艺中浓糖补料和中途排料造成的乙酸积累过多和资源浪费等问题，该研究提出一种稀糖分罐发酵的新工艺。利用30L发酵罐考察稀糖分罐发酵对L-色氨酸发酵的影响在发酵中期(发酵时间为20h左右)将部分发酵液移至另一灭好菌的空罐继续进行发酵并将浓糖替换为稀糖补料。在稀糖分罐发酵工艺条件下菌体生物量、L-色氨酸产量、糖酸转化率分别为44.31g/L、43.82g/L、20%较普通工艺分别提高了5.4%、9.9%和12.36%亿酸积累量较普通工艺下降65.5%。避免了料液的浪费，
关键词稀糖分罐发酵工-色氨酸糖酸转化率之酸
中图分类号TQ922
文章编号.0254-5071(2018)04-0132-05
doi:10.11882/j.issn.02545071.2018.04.025
Effect of diluted glucose fermentation with multiple fermenters on L-tryptophan fermentation
LIU Ziqiang, ZHANG Zhen, CAI Mengmeng, HU Hongtong, CHEN Ning, XU Qingyang
(Tianjin Engineering Lab of Efficient and Green Amino Acid Manufacture, National and Loca/ United Engineering Lab ofMetabolic Controf Fermentation Technology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin 300457, China)
Abstract In order to solve the problems of excessive accumulation of acetic acid and resources waste caused by concentrated glucose feeding and liq-uid releasing during fermentation in the existing L-tryptophan fermentation process, a new process for the fermentation of diluted glucose with multi ple fermenters was proposed. The effect of the new process on L-tryptophan fermentation was investigated by using 30 L fermenter. In the middle of fermentation (about 20 h), some of the fermentation broth was transferred to another empty sterile fermenter to continue the fermentation, and the concentrated glucose was replaced with diluted glucose. Under the conditions of fementation process of diluted glucose fermenters, the mycelia biomass, L-tryptophan yield and glucose acid conversion rate were 44.31 g/L, 43.82 g/L and 20%, respectively, which increased by 5.4%, 9.9% and 12.36% compared with conventional fermentation process, and the accumulation of acetic acid was decreased by 65.5%. The waste of fermentation broth was avoided, the L-tryptophan yield and glucose acid conversion rate were improved and the accumulation of acetic acid was reduced. It had a certain practicability and promotion value in industrial production.
Key words fementation of diluted glucose with multiple fementers; L-tryptophan; glucose acid conversion rate; acetic acid
色氨酸产业近几年来发展迅猛是因其在生命体生长
发育和代谢系统中不可替代的重要作用而逐渐被人开发利用。现在色氨酸在饲料添加剂、食品和医药方面都有非常广泛的应用4。色氨酸的生产方法也由刚开始的化学合成法、酶法、微生物转化法到现在几乎所有色氨酸产业都采用的微生物发酵法因为其原材料易得、工艺步骤相对简单产量高所以非常适合大规模生产()。虽然微生物发醇色氨酸产量高、效益好但是在生产工艺方面仍然存在以下问题，
色氨酸发酵在工业上常采用65%的浓淀粉糖流加补料（实验室采用质量分数为80%的葡萄糖液进行替代）淀粉糖在制作时遇高温发生反应使糖液颜色变深不仅导致
收稿日期2017-12-08
修回日期2018-02-03
培养基的碳源质量降低也给后续提取工作带来困难。而且发酵中期时当装填系数达到一定程度后操作人员会放出部分料液以维持发酵罐正常装填系数放出的料液直接送往提取车间进行产品提取。这时料液中还含有未利用的培养基和具备高产酸活力的菌体提前将其放出会造成菌体活力的浪费导致最终色氨酸产量降低。再有浓糖补料的缺点在于不容易混合均匀导致罐内局部糖浓度分布不均局部浓度过低会影响菌体正常生长局部浓度过高则会使菌体合成副产物乙酸。乙酸浓度过高会抑制细胞生长及重组蛋白合成制约着色氨酸产量和糖酸转化率的进步提升("。这些都一定程度上制约着发酵生产。
为了解决以上存在的问题本研究在现有的发酵工艺
基金项目天津市科技支撑计划重点项目(14ZCZDSY00015）天津市科技特派员项目(15JCTPJC57000）
作者简介刘子强（1993-）男，士研究生研究方向为代谢控制发酵*通讯作者徐庆阳（1980-）男副研究员颈士研究方向为代谢控制发醇
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