Carnitine is a trimethyl amino acid found at relatively high concentra
tions in materials of animal origin. Exogenously provided L-carnitine
was found to stimulate growth of Brevibacterium linens ATCC 19391 in m
edia with inhibitory osmotic strength. Its osmoprotective ability was
as potent as that of glycine betaine. Electrophoretic and spectroscopi
c (NMR) analysis showed that this compound is only transiently accumul
ated, but in significant amounts, by B. linens under hyperosmotic stre
ss and is converted into glycine betaine. The L-carnitine/glycine beta
ine pathway is inducible by L-carnitine in B. linens. The D-enantiomer
did not improve growth of B. linens, even though this solute is accum
ulated by B. linens at the same level as glycine betaine. The two isom
eric forms of carnitine repress the build-up of ectoine, the main endo
genous osmolyte in B. linens.