Reduced activity of
Production of products by engineered bacteria is increased by regulating cellular respiration. Cellular respiration is controlled by reducing electron transfer enzyme activity. Some examples of electron transfer enzymes include NADH dehydrogenases, Succinate dehydrogenases, ubiquinone synthesis, cytochrome O, and cytochrome D. In one example, deletion of UbiCA prevents respiration. Respiration can the be controlled by addition of ubiquinone or expression of ubiCA.
1. An engineered bacterial cell comprising:
a) a disruption in the ubiCA operon, and
b) a vector comprising controlled expression of an exogenous ubiCA gene.
2. The engineered bacterial cell of claim 1 , further comprising reduced activity of an electron transfer enzyme selected from the group consisting of NADH dehydrogenase (NDH), Succinate dehydrogenase (SDH), Cytochrome O (Cyto), Cytochrome D (Cytd), and combinations thereof.
3. The engineered bacterial cell of claim 2 , wherein said cell has a deletion of one or more genes selected from the group consisting of ndh-1, ndh-2, sdh, cyoA, cyoB, cyoC, cyoD, cydA, cydB, and combinations thereof.
4. A method of increasing product yield in an engineered bacterial cell comprising:
a) culturing the engineered bacterial cell of claim 1 ;
b) regulating electron transfer activity by addition of ubiquinone or by manipulating expression of said exogenous ubiCA gene; and
c) isolating a product from said cell.
5. The method of claim 4 , wherein said cell has a deletion of one or more genes selected from the group consisting of ndh-1, ndh-2, sdh, cyoA, cyoB, cyoC, cyoD, cydA, cydB, and combinations thereof.
6. An engineered bacterial cell comprising:
a) a disruption in a ubiA gene, a UbiC gene, or combinations thereof, and
b) a vector allowing controllable expression of an added exogenous ubiCA gene.
7. A method of increasing product yield in an engineered bacterial cell comprising:
a) culturing the engineered bacterial cell of claim 6 ;
b) regulating electron transfer activity in said cell by addition of ubiquinone or by manipulating expression of said added exogenous ubiCA gene; and
c) isolating a product from said cells.