PHYSIOLOGICAL-STUDIES ON INDUCTION AND CATABOLITE REPRESSION OF BETA-XYLOSIDASE AND ENDOXYLANASE IN STREPTOMYCES SP CH-M-1035

The specificity of induction of beta-xylosidase and endoxylanase from Streptomyces sp. CH-M-1035 was investigated using mono-, di- and poly- saccharides, among other compounds. This microorganism was able to gro w on all carbon sources except cellulose microcrystalline and methyl-b eta-D-xylopyranoside. beta-Xylosidase was induced by larchwood xylan, birchwood xylan, oat spelts xylan and D-xylose. Basal levels of activi ty were obtained in sucrose, lactose, maltose and pectin. Endoxylanase activity was induced in presence of xylans, D-xylose, sucrose and D-a rabinose. Both enzymes, beta-xylosidase and endoxylanase, were repress ed by the addition of glucose, glycerol and succinic acid to the cultu re medium containing 1% birchwood xylan. On the other hand, addition o f methyl-beta-D-xylopyranoside in the same conditions induced beta-xyl osidase but not endoxylanase synthesis. An unexpected stimulatory effe ct was observed on beta-xylosidase biosynthesis when pyruvic acid was added to the culture medium independently of the xylan used.