Extracellular enzymatic activities of Bipolaris sorokiniana isolates

Several enzymatic activities were investigated in six isolates of the fungus Bipolaris sorokiniana, originating from different areas of Brazil. Among the glycosidases studied, beta-glucosidase, beta-N-acetylglucosaminidase, beta-xylosidase, cellobiohydrolase, and chitobiohydrolase were the major activities. In some isolates, beta-glucuronidase, beta-galactosidase, and alpha-mannosidase activities were also present. Polysaccharide-hydrolyzing enzymes, such as pectin lyase and carboxymethyl cellulase were detected in significant amounts, and their activities were variable among the different isolates. Other enzymes, namely phosphatases, proteinases and phenol oxidase, were also examined, showing variable amounts depending on the isolate. The pH dependence of all enzymes tested was investigated. Endoproteinase, carboxymethyl cellulase, and phenoloxidase had maximum activity in the pH range of 6-8, whilst all other enzymes showed maximum activity at pH 4-6.