【摘要】 目的:筛选出稳定的高产丁二酮突变菌株,并对其进行发酵动力学分析。方法:以原养型产气肠杆菌(Enterobacter aero-genes编号CICC 10293)为出发菌株,采用紫外线诱变,并结合亮氨酸平板和丁二酮平板筛选方法,获得耐高浓度底物——葡萄糖的高产丁二酮突变菌株,定名为UV-3,利用气相色谱测定代谢产物量,考察诱变前后菌株代谢途径中碳源的流向。基于Logistic和Luedeking-Piret方程,建立突变株UV-3细胞生长动力学、底物消耗动力学、丁二酮生成动力学模型,确定动力学方程。结果:突变株UV-3的丁二酮产量提高18.7倍,达到1.045g.L-1,乙偶姻产量降低48.4%,乙醇产量降低71.4%,乙酸产量提高34.6%,且遗传性质稳定。用实验数据对各种动力学模型进行了验证,拟合度均为98.5%以上。结论:紫外线是一种操作方便,效果良好的诱变方式。绘制了突变株UV-3的发酵曲线,建立了动力学模型,为优化丁二酮的生产工艺奠定一定的理论基础。更多还原

【Abstract】 Objective: To screen a stable,high diacetyl-producing strain and analyse its fermentation kinetics.Methods: A mutant,designated as UV-3,was selected from wild-type Enterobacter aergenes 10293 by application of UV irradiation in combination with cultivation in leucine medium and diacetyl medium.Based on the Logistic equation and Luedeking-Piret equation,three kinetic models were proposed for cell growth,product formation and substrate consumption.Results: Gas chromatography was employed to quantified the output of metabolization,and it was found that the yield of diacetyl for the mutant UV-3 was increased more 18.7 times than that of the wild-type 10293,up to 1.045g·L-1.Acetoin and ethanol yields were decreased by 48.4% and 71.4%,respectively.The yield of acetate was increased by 34.6%.With the data from experiment to evaluate model parameters,the three kinetic models appeared to provide a reasonable description for the fermentation process.Conclusion: The method of UV irradiation for selecting high diacetyl-producing mutants was confirmed to be a good method.Curves of fermention kinetics were described and kinetic models were proposed,which will be helpful for optimizing diacetyl fermentation conditions.更多还原