Attachment to amorphous iron sulfide increases the activity of strictly anaerobic, gallic acid-degrading bacteria

The effect of FeS-coated surfaces on substrate degradation and attachment of strictly anaerobic, gallic acid-fermenting bacteria was examined. Both strains used for this study, Pelobacter acidigallici strain MaGal2 and a newly isolated strain, Pelobacter acidigallici strain EGal, showed an increased degradation rate in the presence of FeScoated surfaces. Surfaces not coated with FeS had no effect compared to the control without added surfaces. For strain EGal, the optimal amount of FeS-coated glass surface for stimulation of degradation was determined. Stimulation was also achieved by addition of dithionite. Control experiments proved that the stimulatory effect of FeS surfaces was not due to a decrease in redox potential or the supply of iron or sulfide.