摘要
以L-色氨酸生产菌Escherichia coli TRP03为供试菌株,研究了多种有机氮源对L-色氨酸发酵的影响。首先对不同来源的酵母粉进行了优化试验,确定一种最优酵母粉,摇瓶发酵时L-色氨酸可积累10.21 g/L;利用5 L发酵罐发酵1.5~3.0 h时,细胞出现二次生长现象,选择添加氨基酸粉和氯化胆碱促进细胞生长,经优化实验,确定同时添加氨基酸粉2 g/L、氯化胆碱0.5 g/L可在很大程度上解决细胞的二次生长问题并提高L-色氨酸产量至44.21 g/L;为提高中后期菌体活力及产酸能力,选择在不同发酵时期流加质量浓度为1 g/L的酵母粉、蛋氨酸及谷氨酰胺混合液,确定10 h流加时,中后期的活细胞数提高了30.18%,保证了菌体活力。菌株E. coli TRP03经36 h发酵,可积累L-色氨酸51.23 g/L,较未经任何优化的菌株提高41.91%。
The effect of various organic nitrogen sources on L-tryptophan fermentation was studied by using L-tryptophan producing strain Escherichia coli TRP03 as test strain. Different sources of yeast powders were optimized to determine an optimal yeast powder, and the L-tryptophan accumulation was 10.21 g/L using shaking flask fermentation. After fermented for 1.5-3.0 h in 5 L fermenter, the secondary growth phenomenon of cell was occurred. To solve the problem, amino acid powder and choline chloride were added to medium to promote the growth of cell, and the addition of amino acid powder and choline chloride was determined as 2 g/L and 0.5 g/L, respectively, which could solve the problem of secondary growth of cell in great extent, and increase the production of L-tryptophan to 44.21 g/L. In order to improve activity and acid production ability of cell in the middle and late stages, the yeast powder, methionine and glutamine mixture with a concentration of 1 g/L were fed in different fermentation periods. When the mixture was fed at 10 h, the viable cell count increased 30.18% in the middle and late stages, and the cell activity was ensured. The L-tryptophan accumulation was 51.23 g/L with fermentation by E. coli TRP03 for 36 h, which was 41.91% higher than that before optimization.
作者
杜丽红
张震
徐庆阳
陈宁
尚永崇
DU Lihong;ZHANG Zhen;XU Qingyang;CHEN Ning;SHANG Yongchong(College of Biotechnology,Tianjin University of Science and Technology,Tianjin 300457,China;National and Local United Engineering Lab of Metabolic Control Fermentation Technology,Tianjin 300457,China;Tianjin Engineering Lab of Efficient and Green Manufacture Amino Acid,Tianjin 300457,China)
出处
《中国酿造》
CAS
北大核心
2019年第5期90-94,共5页
China Brewing
基金
天津市科技支撑计划重点项目(14ZCZDSY00015)
关键词
L-色氨酸
大肠杆菌
发酵
有机氮源
L-tryptophan
Escherichia coli
fermentation
organic nitrogen source
