Biotechnology Bulletin ›› 2015, Vol. 31 ›› Issue (12): 221-226.doi: 10.13560/j.cnki.biotech.bull.1985.2015.12.032

• Research report • Previous Articles     Next Articles

The Knockout of Gene ptsG of Recombinant Escherichia coli Producing D-lactic Acid and the Simultaneous Fermentation of Mixed Sugars

Ding Xiaoyun, Gu Jianjian, Wang Yongze, Zhao Jinfang, Wang Jinhua, Zhao Xiao   

  1. Key Laboratory of Fermentation Engineering of Ministry of Education,Hubei University of Technology,Wuhan 430068
  • Received:2014-12-17 Online:2015-12-19 Published:2015-12-19

Abstract:

In order to construct a recombinant engineering Escherichia coli strain that yields D-lactic acid in the simultaneous efficient fermentation of pentose and hexose, having an engineering E. coli JH13 that efficiently ferment the pentose to produce D-lactic acid as an original strain, a glucose transmembrane transporter gene ptsG was knocked out by the technique of Red homologous recombination. The fermentative results showed that in the 10% mixed sugars(5% glucose and 5% xylose), the ptsG-deleted strain E. coli JH15 simultaneously utilized pentose and hexose to complete the fermentation;however, the control strain started to utilize the xylose only after glucose was consumed up, and 18 g/L xylose still remained after the fermentation completed. The production of D-lactic acid by JH15 reached 83.04 g/L, and 25.86% higher than that by control strain JH13. The JH15 as a E. coli strain of producing D-lactic acid during simultaneous fermentation with mixed sugars, its construction provides a reference for producing the D-lactic acid in fermentation while utilizing the low-cost hydrolyzed components of lignocelluloses materials as raw material.

Key words: recombinant Escherichia coli, D-lactic acid, ptsG, Red homologous recombination, mixed sugars