枯草杆菌 SBS液体发酵联产血栓溶解酶和γ-聚谷氨酸

Co-production of thrombolytic enzyme and γ-polyglutamic acid by liquid-culture of Bacillus subtilis SBS

摘要:

【目的】利用枯草芽胞杆菌(Bacillus subtilis SBS)进行联产血栓溶解酶和γ-聚谷氨酸研究【方法】本研究以实验室自行分离的Bacillus subtilis SBS为出发菌株，进行了液体发酵，通过正交实验研究了碳、氮源对血栓溶解酶和γ-聚谷氨酸联产的影响，并运用多种检测方法对产物进行了鉴定。【结果】在未添加谷氨酸的培养基中合成了γ-聚谷氨酸，表明该菌是非谷氨酸依赖型菌。合成血栓溶解酶的合适碳、氮源分别是可溶性淀粉和大豆蛋白胨，合成γ-聚谷氨酸的合适碳、氮源分别是蔗糖和NH4Cl。【结论】以蔗糖和大豆蛋白胨、NH4Cl分别作为碳源和氮源进行血栓溶解酶和γ-聚谷氨酸的联产。在蔗糖 10 g/L、大豆蛋白胨 20 g/L、NH4Cl 8 g/L时，血栓溶解酶酶活为 265±25 IU/mL，γ-聚谷氨酸产量为1.183±0.015 g/L，均接近了单独合成时的水平。

Abstract:

[Objective] To analyze the co-production of thrombolytic enzyme and γ-polyglutamic acid by liquid-culture of Bacillus subtilis SBS. [Methods] We used Bacillus subtilis SBS to produce thrombolytic enzyme (BTE) and γ-polyglutamic acid (γ-PGA) by liquid fermentation. We conducted orthogonal experiments analysis between carbon source and nitrogen source. Then through Fibrin-SDS-PAGE, UV spectrum, Infra-Red spectrum and high performance liquid chromatography (HPLC), we identified the production. [Results] We synthesized γ-PGA in the medium without the addition of L-glutamic acid. Bacillus subtilis SBS was a L-glutamic acid-independent bacterium. The suitable carbon and nitrogen sources for the synthesis of thrombolytic enzyme (BTE) were soluble starch and soybean peptone. However, the suitable carbon and nitrogen sources for the synthesis of γ-PGA were sucrose and NH4Cl. [Conclusion] The yields of both products could close to the levels of the single synthesis when the concentrations of sucrose, soybean peptone and NH4Cl were 10, 20, 8 g/L respectively, the activity of BTE reached 265±25 IU/mL, and the concentration of γ-PGA reached 1.183±0.015 g/L.