地衣芽孢杆菌发酵生产β-甘露聚糖酶的代谢通量分析

Metabolic Flux Analysis of Bacillus licheniformis for Synthesis of β-Mannanase

基于代谢通量分析理论研究了地衣芽孢杆菌生物合成β-甘露聚糖酶的胞内代谢活动.首先构建了地衣芽孢杆菌产β-甘露聚糖酶的代谢网络,并依据代谢物质量平衡原则建立了反应网络的代谢流模型;进一步采用线性规划的优化方法分别以β-甘露聚糖酶合成反应通量最大和菌体生长速率最大为目标函数对模型进行求解,由此计算得到β-甘露聚糖的最大理论转化率为57.87%.最后对代谢网络中的5个关键节点进行了比较分析,得到了2个类似非刚性的代谢节点(5-磷酸核酮糖节点和草酰乙酸节点),为利用基因工程方法提高β-甘露聚糖酶的生产能力提供了理论依据.

Intracellular metabolic activity of Bacillus licheniformis for synthesis of β-mannanase was studied based on metabolic flux analysis （MFA）. A metabolic network of Bacillus licheniformis for synthesis of β-mannanase was established, and the metabolic mass balance based stoichiometric model of the above network was also built. The metabolic flux model was solved by using linear programming optimization based on the target functions of the metabolic flux distribution of maximum β-mannanase synthesis and maximum cell density. Furthermore, the maximum theoretical yield of β-mannanase from Bacillus licheniformis was calculated as 57.87%. Finally, five important metabolic nodes in the metabolic network of Bacillus licheniformis were analyzed, and two nodes, ribulose 5-phosphate and oxalacetate, were characterized as non-rigid ones, which would guide us to enhance the productivity of β-mannanase using gene engineering.