Utilization of Cellulose Oligosaccharides by Cellvibrio gilvus

Abstract

The hypothesis that oligosaccharides of the cellulose polymer series can be absorbed by cellulolytic, prior to hydrolysis to the level of glucose or cellobiose, has been tested. Resting-cell suspensions of C. gilvus removed oligosaccharides of one to six monomer units from solution at a rate providing the cells with 37 X 106 to 42 X 106 molecules of glucose per cell per minute. There was no concurrent extracellular hydrolysis of the oligosaccharides. The fact that the rate of uptake was constant indicates that an active absorption system is involved. Filtrates from washed-cell suspensions before or after exposure to the oligosaccharides were incapable of hydrolyzing the sugars. In media where the carbohydrate concentration was growth-limiting, the larger members of the oligosaccharide series supported greater final cell densities than the smaller sugars, but there were no recognizable differences in the growth rates during the logarithmic-growth phase.