Biotechnology and Bioprocess Engineering 2019; 24(6): 942-953  
Exogenous Glucose Promotes Growth and Pectinase Activity of Bacillus licheniformis DY2 Through Frustrating the TCA Cycle
Xi Du1, Donghuang Wang1, Di Yin1, Yi Guan1,2,* and Xiuyun Ye1,2,*
1Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou University, Fuzhou, Fujian 350108, China
2College of Biological Sciences and Technology, Fuzhou University, Fuzhou, Fujian 350108, China
Correspondence to: Yi Guan*, Xiuyun Ye*
College of Biological Sciences and Technology, Fuzhou University, Fuzhou, Fujian 350108, China
Tel: 86-591-22866376
E-mail: gy@fzu.edu.cn
E-mail: xiuyunye@fzu.edu.cn
Received: June 25, 2019; Revised: July 16, 2019; Accepted: July 18, 2019; Published online: December 31, 2019.
© The Korean Society for Biotechnology and Bioengineering. All rights reserved.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Microbial pectinases are important sources due to the ease of production and unique physicochemical properties. Here, DY2, a strain of Bacillus licheniformis, was identified from 14 strains of bacteria as a pectinaseproducing bacterium with good application potential. Optimized carbon sources of submerged fermentation led to the identification of glucose as an ideal carbon source for activity and production of P-DY2, the pectinase produced by DY2. GC-MS based metabolomics was used to explore metabolic mechanisms mediated by glucose, showing the frustrated TCA cycle is necessary to elevate the activity and production of P-DY2. Decreased activity of α-ketoglutaric dehydrogenase and succinate dehydrogenase of DY2 in glucose-treated samples supports the conclusion that P-DY2 production is the TCA cycle-independent. These results reveal a metabolic mechanism of high-activity pectinase mediated by exogenous glucose. These findings highlight the way to understand metabolic mechanisms and promote pectinase yield through metabolomics approach and metabolic modulation, respectively.
Keywords: pectinase, glucose, TCA cycle, enzyme activity, metabolites


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