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

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.