Metabolic engineering of Corynebacterium glutamicum for efficient production of succinate from lignocellulosic hydrolysate

Yufeng Mao; Guiying Li; Zhishuai Chang; Ran Tao; Zhenzhen Cui; Zhiwen Wang; Ya-Jie Tang; Tao Chen; Xueming Zhao

doi:10.1186/s13068-018-1094-z

Metabolic engineering of Corynebacterium glutamicum for efficient production of succinate from lignocellulosic hydrolysate

Biotechnol Biofuels. 2018 Apr 4:11:95. doi: 10.1186/s13068-018-1094-z. eCollection 2018.

Authors

Yufeng Mao^#¹, Guiying Li^#¹, Zhishuai Chang^#¹, Ran Tao¹, Zhenzhen Cui¹, Zhiwen Wang¹, Ya-Jie Tang², Tao Chen¹, Xueming Zhao¹

Affiliations

¹ 1Key Laboratory of Systems Bioengineering (Ministry of Education), SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China.
² 2Key Laboratory of Fermentation Engineering, Ministry of Education, Hubei University of Technology, Wuhan, 430068 China.

^# Contributed equally.

Abstract

Background: Succinate has been recognized as one of the most important bio-based building block chemicals due to its numerous potential applications. However, efficient methods for the production of succinate from lignocellulosic feedstock were rarely reported. Nevertheless, Corynebacterium glutamicum was engineered to efficiently produce succinate from glucose in our previous study.

Results: In this work, C. glutamicum was engineered for efficient succinate production from lignocellulosic hydrolysate. First, xylose utilization of C. glutamicum was optimized by heterologous expression of xylA and xylB genes from different sources. Next, xylA and xylB from Xanthomonas campestris were selected among four candidates to accelerate xylose consumption and cell growth. Subsequently, the optimal xylA and xylB were co-expressed in C. glutamicum strain SAZ3 (ΔldhAΔptaΔpqoΔcatP_sod-ppcP_sod-pyc) along with genes encoding pyruvate carboxylase, citrate synthase, and a succinate exporter to achieve succinate production from xylose in a two-stage fermentation process. Xylose utilization and succinate production were further improved by overexpressing the endogenous tkt and tal genes and introducing araE from Bacillus subtilis. The final strain C. glutamicum CGS5 showed an excellent ability to produce succinate in two-stage fermentations by co-utilizing a glucose-xylose mixture under anaerobic conditions. A succinate titer of 98.6 g L^-1 was produced from corn stalk hydrolysate with a yield of 0.87 g/g total substrates and a productivity of 4.29 g L^-1 h^-1 during the anaerobic stage.

Conclusion: This work introduces an efficient process for the bioconversion of biomass into succinate using a thoroughly engineered strain of C. glutamicum. To the best of our knowledge, this is the highest titer of succinate produced from non-food lignocellulosic feedstock, which highlights that the biosafety level 1 microorganism C. glutamicum is a promising platform for the envisioned lignocellulosic biorefinery.

Keywords: Corynebacterium glutamicum; Lignocellulosic hydrolysate; Succinate; Xylose.