Metabolism of D: (+)-carnitine by Escherichia coli.

Escherichia coli 044 K74 grown under anaerobic conditions in the presence of L: (-)-carnitine is able to convert D: (+)-carnitine into the L: (-)-enantiomer. This activity is repressed by electron acceptors such as oxygen and nitrate as well as by glucose. D: (+)-Carnitine shows no effect on the induction or repression of the corresponding enzyme or enzyme system. Resting cells of E. coli 044 K74 were used for the formation of L: (-)-carnitine from D: (+)-carnitine. The maximum obtained yield was 50%. γ-Butyrobetaine was formed as a by-product.