Enumeration and isolation of anaerobic bacteria in sewage digestor fluids: enumeration of sulfate-reducers by the anaerobic roll tube method.

Abstract

Sulfate-reducers in sewage digestor fluids were enumerated by the anaerobic roll tube method. To discriminate them from other bacteria, two media, one of which contained 10% of the supernatant of autoclaved sewage digestor fluid and the other did not, were used. Enumeration of sulfate-reducers was easily carried out with these media by counting black colonies and isolation could also be performed by picking up the colonies without any particular attention. The addition of the sewage digestor fluid to the medium markedly increased the count of sulfate-reducers in the digestor fluid. They were proved to grow well in a richer medium, VLS-lactate agar, which contained Trypticase, yeast extract, 40% of the sewage digestor fluid, and so on. On the contrary, for sulfate-reducers in other environments such as polluted streams, the addition of sewage digestor fluid showed no effect.