Isolation and Characterization of an Anaerobic, Cellulolytic Bacterium, Clostridium cellulovorans sp. nov

Abstract

A new anaerobic, mesophilic, spore-forming cellulolytic bacterium is described. Cellulose is cleared within 24 to 48 h around colonies formed in cellulose agar roll tubes. Cells stain gram negative and are nonmotile rods which form oblong spores either centrally or subterminally in a clostridial swelling. Colonies are irregular with an opaque edge and a center devoid of both vegetative cells and spores. Cellulose, xylan, pectin, cellobiose, glucose, maltose, galactose, sucrose, lactose, and mannose serve as substrates for growth. H 2 , CO 2 , acetate, butyrate, formate, and lactate are produced during fermentation of cellulose or cellobiose. The temperature and pH for optimum growth are 37°C and 7.0, respectively. The DNA composition is 26 to 27 mol% guanine plus cytosine. This bacterium resembles “ Clostridium lochheadii ” in morphological and some biochemical characteristics but is not identical to it. The name Clostridium cellulovorans sp. nov. is proposed. The type strain is 743B (ATCC 35296).