Efficient biosynthesis of 2-keto-D-gluconic acid by fed-batch culture of metabolically engineered Gluconobacter japonicus  

作　　者：Weizhu Zeng Wen Cai Li Liu Guocheng Du Jian Chen Jingwen Zhou 

机构地区：[1]Key Laboratory of Industrial Biotechnology,Ministry of Education and School of Biotechnology,Jiangnan University,1800 Lihu Road,Wuxi,Jiangsu,214122,China [2]National Engineering Laboratory for Cereal Fermentation Technology,Jiangnan University,1800 Lihu Road,Wuxi,Jiangsu,214122,China [3]The Key Laboratory of Carbohydrate Chemistry&Biotechnology,Ministry of Education,School of Biotechnology,Jiangnan University,Wuxi,214122,China [4]Jiangsu Provisional Research Center for Bioactive Product Processing Technology,Jiangnan University,1800 Lihu Road,Wuxi,Jiangsu,214122,China

出　　处：《Synthetic and Systems Biotechnology》2019年第3期134-141,共8页合成和系统生物技术（英文）

基　　金：the National Key Research and Development Program of China(2017YFC1600403);the National Natural Science Foundation of China(31830068,21822806);the Fundamental Research Funds for the Central Universities(JUSRP51701A);the National First-class Discipline Program of Light Industry Technology and Engineering(LITE2018-08);the Distinguished Professor Project of Jiangsu Province.

摘　　要：2-keto-D-gluconic acid(2-KGA)is a key precursor for synthesising vitamin C and isovitamin C.However,phage contamination is as constant problem in industrial production of 2-KGA using Pseudomonas fluorescens.Gluconobacter holds promise for producing 2-KGA due to impressive resistance to hypertonicity and acids,and high utilisation of glucose.In this study,the 2-KGA synthesis pathway was regulated to enhance production of 2-KGA and reduce accumulation of the by-products 5-keto-D-gluconic acid(5-KGA)and D-gluconic acid(D-GA)in the 2-KGA producer Gluconobacter japonicus CGMCC 1.49.Knocking out the ga5dh-1 gene from a competitive pathway and overexpressing the ga2dh-A gene from the 2-KGA synthesis pathway via homologous recombination increased the titre of 2-KGA by 63.81%in shake flasks.Additionally,accumulation of 5-KGA was decreased by 63.52%with the resulting G.japonicas-Δga5dh-1-ga2dh-A strain.Using an intermittent fed-batch mode in a 3 L fermenter,2-KGA reached 235.3 g L^−1 with a 91.1%glucose conversion rate.Scaling up in a 15 L fermenter led to stable 2-KGA titre with productivity of 2.99 g L^−1 h^−1,11.99%higher than in the 3 L fermenter,and D-GA and 5-KGA by-products were completely converted to 2-KGA.

关 键 词：2-Keto-D-gluconic acid GLUCONOBACTER DEHYDROGENASE Homologous recombination Fed-batch fermentation 

分 类 号：O62[理学—有机化学]