Metabolic engineering of for efficient production of succinate from lignocellulosic hydrolysate.

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, was engineered to efficiently produce succinate from glucose in our previous study.

RESULTS

In this work, was engineered for efficient succinate production from lignocellulosic hydrolysate. First, xylose utilization of was optimized by heterologous expression of and genes from different sources. Next, and from were selected among four candidates to accelerate xylose consumption and cell growth. Subsequently, the optimal and were co-expressed in strain SAZ3 (ΔΔΔΔP-P-) 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 and genes and introducing from The final strain 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 was produced from corn stalk hydrolysate with a yield of 0.87 g/g total substrates and a productivity of 4.29 g L h during the anaerobic stage.

CONCLUSION

This work introduces an efficient process for the bioconversion of biomass into succinate using a thoroughly engineered strain of . 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 is a promising platform for the envisioned lignocellulosic biorefinery.