In this study,metabolic pathway engineering using Red recombinase system was performed on Escherichia coli W,a wild type strain,for the production of succinic acid.In order to eliminate the by-product formation of E.coli fermentation,five genes leading for production of lactate(ldhA),formate(pflB) ethanol(adhE),and acetate(poxB and ackA) were deleted from the chromosome.The resulting mutant was then further selected through adaptive(metabolic) evolution for improved anaerobic growth.The evolved strain WS100 could produce succinate as the major fermentation product.In a 15 L fermentation under anaerobic condition using mineral salt medium,WS100 produced 70.13 g/L succinate from 100 g/L glucose in 72 h,with a volumetric productivity of 0.98 g/(L·h) and a yield of 76% based on sugar metabolism.Although small amount of acetate and lactate were still produced as the minor by-products,there was no detectable production of formate and ethanol.This result demonstrated the great potential of the engineered E.coli WS100 for fermentative production of succinic acid at large scale.