摘要
在3.7L发酵罐中研究了溶氧、pH和甘油流加对地衣芽孢杆菌分批发酵生产聚γ-谷氨酸(γ-PGA)的影响.结果表明,当葡萄糖浓度为27.9g/L且通气量控制在4L/min时,搅拌转速达到300r/min即可满足细胞生长和聚γ-谷氨酸合成对溶解氧的需求.不同pH控制方式对聚γ-谷氨酸分批发酵的影响有较大差异.不控制pH时,细胞干重和聚γ-谷氨酸产量比控制pH为5.5的发酵分别低26%和94%.研究了将pH控制在4.0、4.5、5.0、5.5、6.0和6.5的聚γ-谷氨酸分批发酵过程,发现在pH5.5时聚γ-谷氨酸总产量最高.以溶氧水平作为甘油代谢指针来控制甘油限制性流加既可维持一定菌体生长,又不会发生发酵液中残余甘油及有害代谢产物阻遏作用.菌体关于甘油的表观的率、聚γ-谷氨酸的平均比生产速率较没有采用甘油限制性流加时都有所提高.
The effects of dissolved oxygen （ DO）, pH and glycerol feeding on γ-poly （ glutamic acid） （γ-PGA） batch fermentation by Bacillus licheniformis QBL-033 in a stirred fermentor of 3.7 liters were investigated. The resuh showed that DO concentration was an important factor for γ-poly （glutamic acid） production. With initial glucose concentration of 27.9 g/L, 5 L/min air flow rate and agitation rate of less than 300 r/min, the DO concentration was not sufficient to satisfy the oxygen requirement during the fermentation. With agitation rate of more than 300 r/min, the cell growth and γ-poly （ glutamic acid） production were enhanced significantly. When B, licheniformis QBL-033 was cultivated in a batch process without controlling pH, the dry cell mass and γ-poly （ glutamic acid） production were 26% and 94% lower than those at pH 5.5. To assess the effect of pH on γ-poly （ glutamic acid） production, six batch processes controlled at pH 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5 were conducted. The yield was found highest at pH 5.5. To avoid the repression of γ-poly （glutamic acid） caused by residual glycerol and ethanol accumulation due to overfeeding of glycerol, glycerol addition was controlled to produce continuous oscillations in dissolved oxygen, because the change in dissolved oxygen concentration could deliver the information of available carbon source in the fermentation broth. The mean specific y-poly （glutamic acid） productivity and the apparent cell yield on glycerol were higher than those from the fermentation without using the feeding strategy with dissolved oxygen as the indicator of metabolism. Fig 4, Tab 1, Ref 7
出处
《应用与环境生物学报》
CAS
CSCD
北大核心
2006年第6期850-853,共4页
Chinese Journal of Applied and Environmental Biology
基金
山东省优秀中青年科学家科研奖励基金(02BS033)
山东省教育厅科研发展计划基金(J04C09)
曲阜师范大学博士科研启动基金资助~~
作者简介
通讯作者（E-mail：yangge@mail.qfnu．edu．cn）
