A CELLULASE-FREE XYLANASE FROM ALKALI-TOLERANT ASPERGILLUS-FISCHERI FXN1

An alkali-tolerant fungus Aspergillus fischeri Fxn1 isolated from xyla n enrichment grew in the pH range 5-10 and secreted an extracellular c ellulase-free xylanase. Arabinose, lactose, maltose, cellobiose and gl ucose induced low levels of xylanase (1.8-9.0 IU/ml),whereas xylose,xy lan and wheat bran induced higher level (34-45 IU/ml). CMcellulose and FPcellulose did not support growth. The optimum pH of xylanase was 6. 0-6.5 and it was stable in a wide range of pH 5-9.5. The optimum tempe rature was 60 degrees C and it was stable upto 55 degrees C. The half- lives at 50 and 55 degrees C were 240 and 40 min. respectively. This e nzyme released reducing sugars from pulp at pH 9.0 and 40 degrees C.