BIOCONVERSION OF FUMARIC-ACID TO SUCCINIC ACID BY RECOMBINANT ESCHERICHIA-COLI

Succinic acid was produced efficiently from fumaric acid by a recombin ant E. coli strain DH5 alpha/pGC1002 containing multicopy fumarate red uctase genes. The effects of initial fumaric acid and glucose concentr ation on the production of succinic acid were investigated. Succinic a cid reached 41 to over 60 g/L in 48.5 h starting with 50 to 64 g/L fum aric acid. Significant substrate inhibition was observed at initial fu maric acid concentration of 90 g/L. L-Malic acid became the major ferm entation product under these conditions. Provision of glucose (5-30 g/ L) to the fermentation medium stimulated the initial succinic acid pro duction rate over two folds.