MICROORGANISMS AND METHODS FOR THE PRODUCTION OF KETONES
The invention provides a recombinant, acetogenic, carboxydotrophic bacterium that lacks secondary alcohol dehydrogenase or comprises an inactivated secondary alcohol dehydrogenase. The inactivated secondary alcohol dehydrogenase may be encoded by a secondary alcohol dehydrogenase gene comprising an inactivating mutation that reduces the ability of the bacterium to convert acetone to isopropanol and to convert methyl ethyl ketone to 2-butanol. Since a bacterium that lacks secondary alcohol dehydrogenase or comprises an inactivated secondary alcohol dehydrogenase accumulates carbonyl-containing compounds, the invention also provides a method of producing carbonyl-containing compounds, such as acetone and methyl ethyl ketone.
1 . A recombinant, acetogenic, carboxydotrophic bacterium that lacks secondary alcohol dehydrogenase or comprises an inactivated secondary alcohol dehydrogenase.
2 . The bacterium of claim 1 , wherein the bacterium is a member of genus Clostridium.
3 . The bacterium of claim 1 , wherein the bacterium is derived from a bacterium selected from the group consisting of Clostridium autoethanogenum, Clostridium ljungdahlii , and Clostridium ragsdalei.
4 . The bacterium of claim 3 , wherein the Clostridium autoethanogenum is Clostridium autoethanogenum deposited under DSMZ Accession No. DSM23693.
5 . The bacterium of claim 1 , wherein the inactivated secondary alcohol dehydrogenase is inactivated primary-secondary alcohol dehydrogenase.
6 . The bacterium of claim 1 , wherein the inactivated secondary alcohol dehydrogenase is derived from a secondary alcohol dehydrogenase comprising the amino acid sequence of SEQ ID NO: 1.
7 . The bacterium of claim 1 , wherein the inactivated secondary alcohol dehydrogenase is encoded by a secondary alcohol dehydrogenase gene comprising an inactivating mutation.
8 . The bacterium of claim 7 , wherein the secondary alcohol dehydrogenase gene comprising the inactivating mutation is derived from the nucleic acid sequence of SEQ ID NO: 2 or SEQ ID NO: 3.
9 . The bacterium of claim 7 , wherein the inactivating mutation is an insertion.
10 . The bacterium of claim 1 , wherein the bacterium further comprises exogenous genes encoding one or more of a thiolase, a coA-transferase, and an acetoacetate decarboxylase.
11 . The bacterium of claim 1 , wherein the bacterium further comprises an exogenous gene encoding a propanediol dehydratase that converts meso-2,3-butanediol to MEK.
12 . The bacterium of claim 11 , wherein the propanediol dehydratase is a Klebsiella oxtoca propanediol dehydratase.
13 . The bacterium of claim 1 , wherein the bacterium produces one or more of acetone and MEK.
14 . A method of producing acetone, comprising culturing the bacterium of claim 1 , whereby the bacterium produces acetone.
15 . The method of claim 14 , further comprising recovering the acetone from the culture.
16 . A method of producing MEK, comprising culturing the bacterium of claim 1 , whereby the bacterium produces MEK.
17 . The method of claim 16 , further comprising recovering the MEK from the culture.