A mutant of Escherichia coli capable of utilizing 3‐deoxy‐d‐manno‐2‐octulosonic acid as sole carbon source

A mutant of Escherichia coli capable of growth on 3‐deoxy‐d‐manno‐2‐octulosonic acid (KDO) was isolated. Uptake studies showed that no transport of the unaltered molecule into the cell took place. The novel catabolic function which enables the cell to utilize KDO as a substrate appears to be an extracellular degradation in which the carboxyl group is split off as CO2. This reaction is completely inhibited, if another carbon source is added to the growth medium. The structure of the decarboxylated molecule is not known, but uptake experiments suggest that it is transported into the cell by a transport system for which glucose is the normal substrate.