Effects of the growth medium composition on menaquinone homolog formation in Micrococcus luteus.

The menaquinone composition of Micrococcus luteus strains grown in different media was examined. Cells of M. luteus IAM 1056 (type strain) grown in an ordinary complex medium contained MK-8 as the predominant menaquinone. On the other hand, this bacterium produced both MK-8 and MK-8(H2) as major quinones when grown in a chemically defined medium containing glutamate and pyruvate as carbon sources. Unlike the type strain, M. luteus strains IAM 12009 and IAM 12144 had MK-8 (H2) as the major menaquinone, independent of cell growth media. In all strains the total amount of dihydrogenated homologs relative to the total menaquinone content increased more or less in cells grown in the chemically defined medium. Carbon sources and Mg2+ concentrations in the growth medium had minor effects on the menaquinone composition of the M. luteus strains.