Efficient production of succinic acid from corn stalk hydrolysates by a recombinant Escherichia coli with ptsG mutation

Abstract

Succinic acid is considered to be one of the key platform chemicals used in a variety of industrial applications. The exploitation of biomass to produce succinic acid requires a microbial type that can ferment the mixture of reducing sugars derived from lignocellulose. The recombinant Escherichia coli strains with homologous or cyanobacterial ppc overexpression and ldhA, pflB, ptsG mutations were constructed, and the mixed sugar fermentations were carried out with the prominent strain SD121. Then, a modeled corn stalk hydrolysates containing 30 g l −1 glucose, 10 g l −1 xylose and 2.5 g l −1 arabinose was applied for succinic acid fermentation with SD121. A yield of 0.77 g succinic acid g −1 total sugar was achieved. Fermentation of corn stalk hydrolysates with SD121 produced a final succinic acid concentration of 36.55 g l −1 with a higher yield of 0.83 g g −1 total sugar in anaerobic bottles. In two-stage fermentation process in bioreactor, initial aerobic growth facilitated the subsequent anaerobic succinic acid production with a final concentration of 57.81 g l −1, and a yield of 0.87 g g −1 total sugar. This was the first report of succinic acid production from corn stalk hydrolysates by metabolically engineered Escherichia coli. The higher succinic acid yield from corn stalk hydrolysates compared to modeled sugar mixtures, showed a great potential usage of renewable biomass as a feedstock for an economical succinic acid production using E. coli.