Menadione requirement for sulfate-reduction in Desulfotomaculum aeronauticum, and emended species description

Desulfotomaculum aeronauticum strain 9(T) (DSM 10349(T)), previously described as being unable to use sulfate as electron acceptor [X. HAGENAUER, H. HIPPE, and F.A. RAINEY, System. Appl. Microbiol. 20: 65-71 (1997)], was found to he capable of dissimilatory sulfate reduction when menadione was added as a growth factor. Menadione was replacable by vitamin K-1 or 1, 4-naphthoquinone. In media containing menadione, lactate utilization and fermentative growth with pyruvate could also be demonstrated. Menaquinone MK-7 could only be detected in cells grown in the presence of menadione, indicating that the lack of menaquinone is responsible for the inability of cells to use sulfate in the absence of a suitable quinone precursor. In contrast, Desulfitobacterium hafniense strain DCB-2(T) (DSM 10664(T)) which is also incapable of sulfate reduction, synthesized MK-7 when grown in the absence of menadione. Contrary to published results, growth on lactate with thiosulfate could be observed in the latter organism irrespective of whether or not menadione was added. An emended species description of Desulfotomaculum aeronauticum is given.