Engineered zymomonas for the production of 2,3-butanediol
Non-naturally occurring Zymomonas strains useful for the production of 2,3-butanediol are provided.
1. A non-naturally occurring Zymomonas mobilis that does not produce ethanol, lacks a functional pyruvate decarboxylase gene, lacks antibiotic markers and that produces 2,3-butanediol through using the gene products of operably connected exogenous genes acetolactate synthase (ALS), acetolactate decarboxylase (ALDC), and butanediol dehydrogenase (BDH) wherein the exogenous genes are integrated into the chromosomal location of a pyruvate decarboxylase gene of the Zymomonas mobilis ; and wherein the integration of the exogenous genes eliminates the native chromosomal gene for pyruvate decarboxylase; and wherein the Zymomonas mobilis produces 2,3-butanediol in a growth medium that lacks antibiotics; and wherein the 2,3-butanediol produced is at least 96% of the theoretical yield from a carbon source for the production of the 2,3-butanediol; and wherein the 2,3-butanediol is produced up to a concentration of about 120 g/L.
2. The non-naturally occurring Zymomonas mobilis of claim 1 that produces 2,3-butanediol for at least 150 hours.
3. The non-naturally occurring Zymomonas mobilis of claim 1 that produces 2,3-butanediol at about 2.18 g/L/h.
4. The non-naturally occurring Zymomonas species of claim 1 wherein the exogenous genes are endogenous to organisms selected from the group consisting of Bacillus subtilis, Enterobacter cloacae and Serratia marcescens.
5. A method for making 2,3-butanediol using the Zymomonas of claim 1 wherein the method comprises the step of contacting the Zymomonas with at least one sugar selected from the group consisting of glucose and xylose as a carbon source for the production of 2,3-butanediol.