EFFECTS OF CELLOBIOSE ON CELLULOSE COLONIZATION BY A MESOPHILIC, CELLULOLYTIC CLOSTRIDIUM (STRAIN-C401)

When cultured on a mixture of cellobiose and cellulose, Clostridium C4 01 did not initially attach to cellulose but remained in the liquid ph ase. After cellobiose exhaustion, bacterial cells grew in association with the insoluble cellulose. Carboxymethylcellulase (CMCase) producti on on Avicel cellulose was four- to fivefold greater than on cellobios e, and cellulose-grown cells adhered to filter paper with an initial a dhesion rate about four- to fivefold greater than did cellobiose-grown cells. Using tritiated thymidine incorporation as a measure of growth , it appeared that transfer of strain C401 from cellobiose to cellulos e required an adaptation phase. An extracellular cellulase complex was isolated by affinity chromatography. This enzyme system is a multicom ponent aggregate (molecular mass above 5 MDa), and yielded two major p olypeptide bands by SDS-PAGE having molecular masses of 130 and 70 kDa . Cellobiose strongly inhibited Avicelase activity and slightly inhibi ted p-nitrophenylcellobiose hydrolysis (pNPCbase), but had no effect o n the CMCase activity of the cellulase complex. In addition, polyclona l antibodies, raised against the purified 130 kDa protein inhibited Av icelase activity, but not CMCase and pNPCbase activities.