The utilization of D- and L-amino acids with acidic, basic or polar side ch
ains was demonstrated by HPLC. Two species of the anaerobe Fusobacterium ut
ilized D-lysine and the L isomers of glutamate, glutamine, histidine, lysin
e and serine. Only F. varium used L-arginine, D-glutamate and D-serine as s
ubstrates, whereas F. nucleatum specifically utilized D-histidine and D-glu
tamine. D-Glutamate accumulated in F. nucleatum cultures supplemented with
D-glutamine, and ornithine was detected when either DL- or L-arginine was i
ncluded in F. varium cultures. Based on literature precedents, D-glutamate
and D-histidine are isomerized to their L isomers prior to degradation, but
separate catabolic pathways are possible for each enantiomer of lysine and
serine.