The endogenous pnp gene encoding polynucleotide phosphorylase in the Zymomonas genome was identified as a target for modification to provide improved xylose utilizing cells for ethanol production. The cells are in addition genetically modified to have increased expression of ribose-5-phosphate isomerase (RPI) activity, as compared to cells without this genetic modification, and are not limited in xylose isomerase activity in the absence of the pnp modification.
STATEMENT OF GOVERNMENT RIGHTS
This invention was made with United States government support under Contract No. DE-FC36-07GO17056 awarded by the Department of Energy. The government has certain rights in this invention.