Bacterial assimilation of sulfonate-sulfur under anaerobic conditions
has been demonstrated. Two different bacteria able to grow fermentativ
ely using sulfonate-sulfur as sole sulfur source were isolated by enri
chment culture; neither were able to utilize sulfonates as sole source
of carbon and energy for growth. The isolate of Clostridium pasteuria
num assimilated the sulfur of isethionate (2-hydroxyethanesulfonate),
taurine (2-aminoethanesulfonate), or p-toluenesulfonate. A facultative
ly fermentative Klebsiella strain did not utilize the sulfur of any of
these sulfonates, but assimilated cysteate-sulfur; in contrast, when
growing by aerobic respiration, the range of sulfonates able to serve
as sulfur source was greater. Both bacteria displayed a preferential u
tilization of sulfate-sulfur to that of the sulfonates tested. Thus, b
acterial assimilation of sulfonate-sulfur during anaerobic growth has
direct parallels with features until now recognized only for aerobic a
ssimilatory processes.