The isolation of anaerobic cellulose-decomposing bacteria from soil.

Abstract

SUMMARY: A strictly anaerobic mesophilic species of cellulose-decomposing bacteria was isolated from soil by a new technique. Cultures were made in screw-capped bottles with media containing finely divided cellulose. The method and apparatus used for filling these bottles with reduced media and nitrogen is described. Flocculation of cellulose particles in agar media was prevented by incorporating a low concentration of sodium carboxymethyl cellulose. Cellulolytic colonies in cellulose agar media were of two types, punctiform and spreading. The isolate derived from a punctiform colony digested cellulose with the formation of formic, acetic and malic acids, carbon dioxide and hydrogen. Essential growth factors were provided by yeast and soil extracts. Surface colonies on yeast peptone cellobiose agar were differentiated into convex entire central zones and thin transparent irregular margins. In deep culture with the same medium the isolate grew either as discrete lenticular colonies or spread rapidly throughout the agar. These growth forms were unstable, the type appearing in any one culture being unpredictable. In many respects the isolate resembles Clostridium cellobioparum Hungate, and is probably a strain of this species. It differs from C. cellobioparum, however, in producing little or no cellobiose but abundant glucose from cellulose in liquid culture.