EFFICIENT PRODUCTION OF MANNAN-DEGRADING ENZYMES BY THE BASIDIOMYCETESCLEROTIUM-ROLFSII

Sclerotium rolfsii CBS 191.62 was cultivated on a number of carbon (C) sources, including mono-and disaccharides, as well as on polysacchari des, to study the formation of different mannan-degrading enzyme activ ities. Highest levels of mannanase activity were obtained when alpha-c ellulose-based media were used for growth, but formation of mannanase could not be enhanced by employing galactomannan as the only carbon so urce. Although both xylanase and cellulase formation was almost comple tely repressed when S, rolfsii was grown on more readily metabolizable carbohydrates, including glucose or mannose, considerable amounts of mannanase activity were secreted under these growth conditions. Enhanc ed mannanase production only commenced when glucose was depleted in th e medium. The maximal mannanase activity of 240 IU/mL obtained in a la boratory fermentation is remarkable. Mannanase activity formed under t hese derepressed conditions could be mainly attributed to one major, a cidic mannanase isoenzyme with a pI value of 2.75.