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目的:研究乳酸对克雷伯氏肺炎杆菌(Klebsiella pneumonia)产1,3-丙二醇的影响。方法:通过在摇瓶和反应器水平下分析不同菌株(包含无乳酸、2,3-丁二醇产生的基因敲除菌)的乳酸代谢特性。结果:前期添加6 g/L的乳酸使1,3-丙二醇的产量降低了19%,而发酵10h后添加乳酸几乎不表现出抑制作用。通过对乳酸敲除菌株的代谢分析发现,发酵后期能够消耗培养基中的乳酸,这在一定程度上也反映了菌体发酵后期对乳酸的耐受性。结论:乳酸的抑制作用主要发生在1,3-丙二醇发酵的前期。解除了一株无副产物2,3-丁二醇生产株前期乳酸的过早积累后,1,3-丙二醇的的产量提高了56%。
Objective: To study the effect of lactate on 1,3-propanediol production by Klebsiella pneumonia. Methods: The lactic acid metabolic profiles of different strains (including gene knockout bacteria produced from 2,3-butanediol free of lactic acid) were analyzed at shake flask and reactor levels. Results: The pretreatment with 6 g / L lactic acid reduced the production of 1,3-propanediol by 19%, while the addition of lactic acid after 10 h fermentation showed almost no inhibitory effect. Metabolic analysis of lactate knockout strains found that the late fermentation can consume the medium of lactic acid, which to some extent also reflects the lactic acid tolerance of the bacterial fermentation late. Conclusion: The inhibitory effect of lactic acid mainly occurs in the prophase of 1,3-propanediol fermentation. After premature lactic acid buildup in a strain of 2,3-butanediol-free production of a by-product was lifted, 1,3-propanediol production increased 56%.