摘要
目的:生物法合成1,3-丙二醇时,pH值对于产物谱有着显著影响。本文将研究不同pH值对克雷伯氏肺炎杆菌(Klebsiella pneumoniae)的中心碳代谢的影响。方法:设计单因素试验,控制发酵pH值,用5L Braun发酵罐进行批次发酵,分析发酵过程中产物时序性合成的特性。结果:pH 6.2到7.4适合菌体生长;不同pH值对于葡萄糖消耗无明显差异;pH6.8时能在较长时间保持在高水平的甘油比消耗速率;在偏碱性条件下,有机酸丁二酸、乳酸、乙酸的比生长速率显著增大;而2,3-丁二醇在偏碱性的pH7.4和8.0时根本不能合成。pH6.8时1,3-丙二醇的得率最大,不同pH条件下碳回收率相当。结论:证明了pH值对K. pneumoniae中心碳代谢具有显著影响,不同产物呈现不同的合成动力学特性,其详细机理有带进一步深入研究。
pH exhibited the significant influences to the end product spectrum in the biosynthesis of 1,3 - propaaediol. The effects of pH on Klebsiella pneumoniae central carbon metabolism were investigated in details. Methods： The batch factorial experiments were conducted under different pH conditions with 51 Braun B Plus fermenter to analyze the properties of the sequential product synthesis. Results： pH 6.2 to 7.4 was appropriate for the growth of K. pneumoniae. It was noticed the specific consumption rate of glucose present the similar evolution behaviors under different pH conditions. The specific consumption rate of glycerol could maintain the high level for a longer period at pH6.8. The production of succinate, lactate, and acetate were preferred in the alkaline environment facilitated. In contrast, no 2,3 - butanediol was synthesized at pH 7.4 and 8.0. The maximum 1,3 - pmpanediol yield was obtained at pH6.8. The carbon recovery was similar under the different condition. Conclusion：This work confirmed that pH play the important role in the central carbon metabolism of K. pneumoniae. It revealed that the different end product presented different dynamic synthesis characterization.
出处
《生物技术》
CAS
CSCD
2007年第5期74-77,共4页
Biotechnology
基金
国家863计划项目资助(2006AA020103)
