Reisolation of Ruminobacter parvum.

A cellulolytic gram-negative ovoid motile rod (strain GS III) was isolated from an in vitro incubation of ground barley straw in rumen fluid. The anaerobic, non-sporulating, mesophilic organism strongly answered the original description of Ruminobacter parvum (Kaars Sijpesteijn, 1948). The strain GS III fermented pyruvate, D-arabinose, D-xylose, cellobiose, sucrose, maltose, cellulose, dextrin, xylan and pectin. Products from cellobiose were D-lactate, ethanol, acetate, hydrogen and carbon dioxide. A heat-resistant factor in yeast extract that was not a B-vitamin, a metal or one of the volatile fatty acids was required for growth. The mol % G + C was 51.9. The organism was lost after prolonged subculture.