植物乳杆菌ZS2058生物转化共轭亚油酸的反应动力学

Bioconversion kinetics of conjugated linoleic acid by Lactobacillus plantarum ZS2058

摘要:

摘要：【目的】对本实验室从泡菜中筛选到的植物乳杆菌ZS2058完整细胞生物转化共轭亚油酸的反应动力学进行研究。【方法】探讨底物浓度、细胞浓度、反应体系pH值等因素对生物转化共轭亚油酸反应速度的影响，并通过双倒数和Hanes-Woolf作图法拟合反应初始阶段的速度方程。【结果】生物转化共轭亚油酸时存在明显的底物抑制现象，当亚油酸浓度为0.4 mg/mL时产c9, t11-共轭亚油酸的反应速度达最大值15.99 μg/(mL?h)；反应速度随细胞浓度增加而上升，当细胞浓度为5×1010 cfu/mL时反应速度达到最高；最适pH值和最适反应温度分别为6.5和40 ℃。利用双倒数和Hanes-Woolf作图法求得米氏常数和最大反应速度，在低底物浓度下，反应初始阶段的反应规律与经典的米氏方程相符，而在高底物浓度下，存在明显的底物抑制现象。【结论】通过对植物乳杆菌ZS2058完整细胞催化合成共轭亚油酸各因素的考察，在得到最佳反应条件的同时建立了不同底物浓度范围内的反应速度方程，这对于实现共轭亚油酸的生产和研究其生理功能具有十分重要的理论价值。

Abstract:

Abstract: [Objective] Studying the kinetics of conjugated linoleic acid (CLA) bioconversion by Lactobacillus plantarum ZS2058. [Methods] We investigated the effects of the substrate concentration, cell mass, reaction pH and temperature on the reaction rate of producing CLA by L. plantarum ZS2058, and established the equations of reaction rate at the initial response stage under different substrate concentrations by double-reciprocal plot and Hanes-Woolf plot method. [Results] The results showed that there existed in a marked substrate inhibition effect, and the early reaction rate of producing c9, t11-CLA reached the maximum of 15.99 μg/(mL?h) when linoleic acid concentration was 0.4 mg/mL. The early reaction rate ascended with the cell mass increasing, and when the cell mass was at 5×1010 cfu/mL, the response rate close to the maximum. The optimum pH and temperature of bioconversion of CLA were 6.5 and 40℃ respectively. Michaelis constant was obtained by double-reciprocal plot and Hanes-Woolf plot method, the reaction rate equation followed the classic Michaelis-Mentent equation at the low substrate concentration, while there existed in a marked substrate inhibition effect at the high substrate concentration. [Conclusion] Through exploring the various factors of CLA bioconversion by L. plantarum ZS2058, we established the reaction rate equations of the initial response stage under different substrate concentrations, and got the optimal reaction conditions. These results will contribute to the CLA production and its physiological functions research.