PURIFICATION AND PROPERTIES OF 3 XYLANASES FROM ASPERGILLUS-ACULEATUS

Three distinct extracellular xylanases (FIa-, FIb-, and FIII-xylanases) from a culture filtrate of Aspergillus aculeatus No. F-50 were purified to homogeneity by SDS polyacrylamide gel electrophoresis. The molecular weights of FIa-, FIb-, and FIII-xylanases were estimated to be 18,000, 26,000, and 52,000, and their pi values were pH 5.6, 9.0, and 3.8, respectively. The pH optima of xylanase activities were from 4.5 to 5.0. The optimum temperatures for enzyme activities were from 50 degrees C to 70 degrees C. All three xylanases were highly specific for xylan hydrolysis, and they did not cleave xylobiose.