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›› 2010, Vol. 10 ›› Issue (4): 777-780.

• 生化工程专栏 • 上一篇    下一篇

全细胞催化合成医用纺织新材料聚g-谷氨酸

杨革 王宁 张超   

  1. 天津工业大学纺织学院 山东曲阜师范大学生命科学学院 山东曲阜师范大学生命科学学院
  • 收稿日期:2010-05-14 修回日期:2010-07-05 出版日期:2010-08-20 发布日期:2010-08-20
  • 通讯作者: 杨革

Synthesis of New Medical Textile Material Poly(g-glutamic acid) by Whole-cell Biocatalysis

YANG Ge, WANG Ning, ZHANG Chao,   

  1. School of Textile, Tianjin Polytechnic University College of Life Science,Qufu Normal University, College of Life Science,Qufu Normal University,
  • Received:2010-05-14 Revised:2010-07-05 Online:2010-08-20 Published:2010-08-20
  • Contact: YANG Ge,

摘要: 在3.7 L生物反应器中研究了反应条件对固定化地衣芽孢杆菌催化合成聚g-谷氨酸的影响. 结果表明,添加赖氨酸与谷氨酰胺都可加强产物的合成,反应体系温度37℃及pH值7.0、催化剂用量4%(w)、通气量4 L/min时,搅拌转速达300 r/min即可满足细胞的基础代谢和聚g-谷氨酸合成对溶解氧的需求. 以溶氧水平作为L-谷氨酸代谢指标控制L-谷氨酸限制性流加,既可维持一定的固定化菌体的基础代谢,又不会发生反应体系中残余谷氨酸及有害代谢产物阻遏作用,聚g-谷氨酸转化得率最高可达92.74%. 全细胞生物催化剂反应5次后聚合得率可保持在81%以上.

关键词: 聚g-谷氨酸, 全细胞催化, 地衣芽孢杆菌

Abstract: The effects of reaction system conditions on poly(g-glutamic acid) production by immobilized Bacillus licheniformis WBL-3 in a 3.7 L stirred bioreactor were investigated. The results showed that total poly(g-glutamic acid) production was increased by lysine and L-glutamine, under the conditions of reaction system temperature 37℃, pH 7, amount of whole cell biocatalyst 4%(w), and agitation speed of 300 r/min, the cell metabolism and poly(g-glutamic acid) production are enhanced significantly, and the DO concentration is sufficient to satisfy the oxygen requirement during the reaction. To avoid the repression of poly(g-glutamic acid) expression caused by residual glutamic acid and ethanol accumulation due to overfeeding of glutamic acid, glutamic acid addition was controlled to produce continuous oscillations in dissolved oxygen, because the change of dissolved oxygen concentration could deliver the information of available carbon source in the reaction broth, optimum yield of poly(g-glutamic acid) reached 92.74%. The whole-cell biocatalyst showed a good catalytic capability for repeated use and the yield of poly(g-glutamic acid) could still maintain 81% after it was used for five times.

Key words: poly(g-glutamic acid), immobilized whole-cell, Bacillus licheniformis

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