Xylanolytic activity of thermophilicSporotrichum sp. andMyceliophthora thermophilum

Abstract

Extracellular xylanase of 5 isolates of thermophilicSporotrichum sp. andMyceliophthora thermophilum was studied in media containing wheat straw, wheat bran, paddy straw, paddy husk, sugar cane bagasse and local grass (Cyanodon dactylon L). Maximum D-xylanase (0·92 IU/ml) was secreted on 6th day bySporotrichum sp. strain 1 in a basal medium that contained 5% (w/v) wheat straw; treatment of straw by 4% NaOH prior to fungal fermentation did not alter xylanase yields appreciably. Temperature and pH optima for enzyme production were 45°C and 5·0 respectively. Enzyme activity showed a temperature optima of 70°C, pH maxima of 5·5 and a substrate level of 3% larch wood xylan. Xylanase ofSporotrichum sp. strain 1 was inducible and highly thermostable; nearly 70% of activity was retained even after 5 min exposure at 80°C. Associated cellulolytic activity (0·12 IU/ml) was detected in the crude enzyme preparation.