Controlling catabolite repression for isobutanol production using glucose and xylose by overexpressing the xylose regulator

• Published in: Journal of biotechnology Vol. 359; pp. 21 - 28
• Main Authors: Lee, Hong-Ju, Kim, Byungchan, Kim, Suhyun, Cho, Do-Hyun, Jung, Heeju, Bhatia, Shashi Kant, Gurav, Ranjit, Ahn, Jungoh, Park, Jung-Ho, Choi, Kwon-Young, Yang, Yung-Hun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 20.11.2022
• Subjects: Carbon catabolite repression; Isobutanol production; Sugar utilization; xylR; Isobutanol production; Carbon catabolite repression; Sugar utilization; xylR
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2022.09.012

Using lignocellulosic biomass is immensely beneficial for the economical production of biochemicals. However, utilizing mixed sugars from lignocellulosic biomass is challenging because of bacterial preference for specific sugar such as glucose. Although previous studies have attempted to overcome this challenge, no studies have been reported on isobutanol production from mixed sugars in the Escherichia coli strain. To overcome catabolite repression of xylose and produce isobutanol using mixed sugars, we applied the combination of three strategies: (1) deletion of the gene for the glucose-specific transporter of the phosphotransferase system (ptsG); (2) overexpression of glucose kinase (glk) and glucose facilitator protein (glf); and (3) overexpression of the xylose regulator (xylR). xylR gene overexpression resulted in 100% of glucose and 82.5% of xylose consumption in the glucose–xylose mixture (1:1). Moreover, isobutanol production increased by 192% in the 1:1 medium, equivalent to the amount of isobutanol produced using only glucose. These results indicate the effectiveness of xylR overexpression in isobutanol production. Our findings demonstrated various strategies to overcome catabolite repression for a specific product, isobutanol. The present study suggests that the selected strategy in E. coli could overcome the major challenge using lignocellulosic biomass to produce isobutanol. •Discovering of various strategies to avoid carbon catabolite repression in E. coli.•Identifying the cell growth, sugar consumption and isobutanol in mixed sugar medium.•Simultaneous glucose and xylose consumption was observed in xylR overexpressed HJ02.•Enhancing Isobutanol titer from 1.98 g/L into 4.75 g/L in xylR overexpressed HJ02.