I just began working with E. coli K-12 for use as an oxygen scavenger in my reactors. I'm growing them on glucose, but since glucose is fermented I expect it to be quickly depleted in my reactor since I cannot reinject for reasons I won't go into. Once their food source is depleted, they'll no longer be able to reduce the O2 that periodically enters. I'd like to give E. coli a non-fermentable substrate that requires O2 as an electron acceptor. This will maintain a low level of continuous growth as O2 slowly leaks into my reactor since the cells can only grow when O2 is present. Can someone give me a short list of electron donors that E. coli can grow on with O2, but not without?