a process for preparing polyvalent , physiologically degradable carbohydrate - containing polymers by enzymatic glycosylation reactions is described . the carbohydrate - containing polymers thus prepared may be used for preparing carbohydrate building blocks . the polyvalent carbohydrate - containing polymers of the invention cause no intolerance reactions in vivo , either in their intact form or in the form of degradation products . the carbohydrate side chain of the carbohydrate - containing polymer is assembled by enzymatic glycosylation reactions in homogeneous aqueous buffer systems directly on a biodegradable polymer . the yields of the glycosylation reaction are significantly improved over known processes , and are often quantitative . this also provides a significant increase in the loading densities . a process for preparing free oligosaccharides by means of the carbohydrate - containing polymers of the invention is also described .