| 利用低pH胁迫作用促进产朊假丝酵母生产谷胱甘肽 |
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| 引用本文： | 聂薇,卫功元,李寅,堵国成,陈坚.利用低pH胁迫作用促进产朊假丝酵母生产谷胱甘肽[J].化工学报,2005,56(9):1750-1756. |
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| 作者姓名： | 聂薇 卫功元 李寅 堵国成 陈坚 |
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| 作者单位： | 江南大学工业生物技术教育部重点实验室;生物工程学院环境生物技术研究室,江苏 无锡 214036 |
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| 基金项目： | 江苏省高校高新技术产业发展项目（JH02-101）：高等学校优秀青年教师教学科研奖励计划. |
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| 摘 要： | 谷胱甘肽（GSH）在生物细胞抵御外界环境条件的刺激和胁迫时起到非常重要的作用.研究发现，高产GSH的产朊假丝酵母（Candida utilis）在受到低pH胁迫时，能以增加GSH合成并向胞外释放GSH的方式来响应和抵御外界pH的不断降低.根据这一生理现象，设计了一种pH控制策略，即在C.utilis WSH 02-08发酵过程中，对细胞赋予短时间pH胁迫，以期提高其胞内GSH合成能力，并使GSH向胞外分泌，从而改变GSH在胞内外的分布和增加GSH合成总量.在该发酵策略的控制下，GSH总产量达到737.1 mg•L-1，比对照(A：初糖浓度60 g•L-1，恒定pH=5.5，培养时间48 h;B：初糖浓度30 g•L-1，24 h一次性补料30 g•L-1，恒定pH=5.5，培养时间45 h)分别高出24.9% 和 20.0%;胞外GSH含量达到197.3 mg•L-1，比对照（A、B同前）分别高出355.7% 和 455.8%;单位细胞的GSH含量达到2.67%（mass），而对照仅为2.28%（mass）和 2.11%（mass）.研究表明，基于微生物细胞的生理特性设计发酵策略，可以较大幅度地提高目标发酵产物的产量.
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| 关 键 词： | 谷胱甘肽 产朊假丝酵母 发酵 低pH胁迫策略 |
| 文章编号： | 0438-1157（2005）09-1750-07 |
| 收稿时间： | 09 13 2004 12:00AM |
| 修稿时间： | 2004-09-132004-11-16 |
Enhanced intracellular glutathione synthesis and export capability of Candida utilis by using low pH-stress strategy |
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| NIE Wei,WEI Gongyuan,LI Yin,DU Guocheng,CHEN Jian.Enhanced intracellular glutathione synthesis and export capability of Candida utilis by using low pH-stress strategy[J].Journal of Chemical Industry and Engineering(China),2005,56(9):1750-1756. |
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| Authors: | NIE Wei WEI Gongyuan LI Yin DU Guocheng CHEN Jian |
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| Abstract: | When Candida utilis WSH 02-08 was cultivated in a glucose-ammonium sulfate medium without pH control, glutathione leakage occurred when the pH of the medium decreased to 1.5. However, analysis of the cell viability indicated that the cells were not lysed. To further study the effect of low pH stress on glutathione production, pH-controlled batch cultures were conducted, where the pH was switched from 5.5 to 1.2 at 24 h and stood at 1.2 for 6 h.Nearly all intracellular glutathione leaked into the medium and the cell viability decreased dramatically, conceiving the idea that a long-term exposure of strain WSH 02-08 at low pH environment led to a complete cell lysis. A critical point (treated at pH 1.2 for 3 h) was experimentally determined, where most cells were alive but suffering a low pH stress. Low pH-stressed C. utilis cells displayed an increased intracellular glutathione synthesis and export capability, which protected cells against short-term low pH treatment. This is the first report of glutathione secretion of C. utilis at low pH. Using this knowledge, a low pH-stress strategy was developed and applied to fed-batch production of glutathione.A 197.3 mg•L-1 of glutathione was secreted into the medium.The total glucose concentration reached 737.1 mg•L-1，increasing by 24.9% and 20.0% respectively than two control cases,and the glutathione content reached 2.67 %（mass）,as compared to two control cases of 2.28%(mass)and 2.11%(mass).This study demonstrated the importance of a physiology-based fermentation strategy in the production of useful compounds. |
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| Keywords: | glutathione Candida utilis fermentation low pH-stress strategy |
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