The effect of the carbohydrate growth substrate on the glycosidase activity of hemicellulose‐degrading rumen bacterial isolates

Thirteen strains of hemicellulose‐degrading bacteria isolated from the rumen were grown on ten different monosaccharide, disaccharide and hemicellulosic poly‐saccharide substrates in vitro , and the range and specific activities of the glycosidase enzymes formed were determined. Alkaline phosphatase activities were also measured. The specific activities were affected by the carbohydrate source supplied in the growth medium and were usually reduced in glucose grown cells, and less frequently following growth on cellobiose; the responses to other substrates were both enzyme and organism dependent. In several of the strains examined many of the enzymes were found following growth on all of the substrates tested, although there were wide variations in the specific activities. The activities of several of the glycosidases were increased after growth on hemicellulosic polysaccharides.