INDUCTION OF XYLANASE AND BETA-XYLOSIDASE IN CELLULOMONAS-FLAVIGENA GROWING ON DIFFERENT CARBON-SOURCES

When Cellulomonas flavigena CDBB-531 was grown on glucose, xylose, gly cerol, solka floc, sugarcane bagasse or xylan, xylanase activity was f ound only in the fermentation broth, while beta-xylosidase activity wa s always associated with the cells. Both enzymes were inducible, sugar -cane bagasse was the best inducer, solka flee and avicel were moderat ely good, while xylan was poor. A synergistic effect on xylanase and b eta-xylosidase synthesis was observed when cellulose and hemicellulose were used together as carbon sources. When this strain was grown on g lucose, cellobiose, arabinose or xylose, only low levels of both enzym es were detected. These results indicate that xylanase and beta-xylosi dase were carbon-source-repressed by readily metabolizable substrates. The effect of glycerol on enzymes that were already induced was studi ed. The addition of glycerol caused a significant decrease in the leve ls of xylanases, while beta-xylosidase activity remained unchanged.