Succinate Production with Metabolically Engineered Escherichia coli Using Elephant Grass Stalk (Pennisetum purpureum) Hydrolysate as Carbon Source

Abstract

Succinic acid is a spectacular chemical that can be used as the precursor of various industrial products including pharmaceuticals and biochemicals. The improvement of the succinic acid market depends on strains engineering that is capable of producing succinic acid at high yield and excellent growth rate which could utilize the wide range of carbon sources such as renewable biomass. Here we use counter selection using catAsacB for pathway design and strains developments. In this investigation, metabolically engineered Escherichia coli M6PM strain was constructed for the synthesis of succinic acid using elephant grass stalk (Pennisetum purpureum) as a carbon source. Elephant grass stalk hydrolysate was prepared which comprised of 11.60 ± 0.04 g/L glucose, 27.22 ± 0.04 g/L xylose and 0.65 ± 0.04 g/L arabinose. Metabolically engineered E. coli M6PM was constructed and fermentation with pure sugars revealed that it could utilize xylose and glucose efficiently. E. coli M6PM produced a final succinate concentration of 30.03 ± 0.02 g/L and a yield of 1.09 mol/mol during 72 h dual-phase fermentation using elephant grass stalk hydrolysate, which resulted in 64% maximum theoretical yield of succinic acid. The high succinate yield from elephant grass stalk demonstrated possible application of renewable biomass as feedstock for the synthesis of succinic acid using recombinant E. coli.