STRAINS OF ESCHERICHIA COLI MODIFIED BY METABOLIC ENGINEERING FOR THE PRODUCTION OF SUCCINIC ACID FROM GLUCOSE, XYLOSE OR A GLUCOSE-XYLOSE MIX, AS A SOURCE OF CARBON.

摘要

The present disclosure is related to new strains of Escherichia coli that use the phosphoenolpyruvate carboxykinase (Pck) enzyme, as the main carboxylation pathway of phosphoenolpyruvate to oxaloacetate, to produce succinic acid with a high yield from glucose, xylose or a glucose-xylose mixture as a carbon source. The new strain, called MS01 frdA Ptrcpck, was obtained with the integration of the pck gene into a chromosome under the control of an inducible promoter, and the other new strain called MS01 frdA Ptrcpck Appc, was obtained with the elimination of the ppc gene, that encodes the pyruvate carboxylase enzyme. The present invention also comprises a fermentation method in mineral medium with glucose, xylose or a glucose-xylose mixture, as a carbon source, which, using the new strains of E. coli, referred above, is used for the production of succinic acid. Particularly referring to the fermentative methods to produce succinic acid from mineral medium with glucose, xylose or a glucose-xylose mixture, as a carbon source, with low oxygen transfer rates. The reintegration of the frdA gene, into a non-fermentative strain of E. coli, allowed the new strains to produce succinic acid with high yields under low oxygen transfer rates (VTO) conditions, being the best production method, the one that provided a VTO of 2.24 mmol O2 L-1 h-1.