文章基本信息

标题：Production of diacetyl by metabolically engineered Enterobacter cloacae
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作者：Lijie Zhang ; Yingxin Zhang ; Qiuyuan Liu 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2015
卷号：5
期号：1
DOI：10.1038/srep09033
语种：English
出版社：Springer Nature
摘要：Diacetyl, a high value product that can be extensively used as a food ingredient, could be produced from the non-enzymatic oxidative decarboxylation of α-acetolactate during 2,3-butanediol fermentation. In this study, the 2,3-butanediol biosynthetic pathway in Enterobacter cloacae subsp. dissolvens strain SDM, a good candidate for microbial 2,3-butanediol production, was reconstructed for diacetyl production. To enhance the accumulation of the precursor of diacetyl, the α-acetolactate decarboxylase encoding gene ( budA ) was knocked out in strain SDM. Subsequently, the two diacetyl reductases DR-I ( gdh ) and DR-II ( budC ) encoding genes were inactivated in strain SDM individually or in combination to decrease the reduction of diacetyl. Although the engineered strain E. cloacae SDM (Δ budA Δ budC ) was found to have a good ability for diacetyl production, more α-acetolactate than diacetyl was produced simultaneously. In order to enhance the nonenzymatic oxidative decarboxylation of α-acetolactate to diacetyl, 20 mM Fe³⁺ was added to the fermentation broth at the optimal time. In the end, by using the metabolically engineered strain E. cloacae SDM (Δ budA Δ budC ), diacetyl at a concentration of 1.45 g/L was obtained with a high productivity (0.13 g/(L·h)). The method developed here may be a promising process for biotechnological production of diacetyl.