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An extracellular multiple form of endoxylanase was isolated from the xylanolytic complex of Aspergillus niger B03. Th e enzyme was purifi ed to a homogenous form using ultrafi ltration, anion exchange chromatography, and gel fi ltration. It was a nonglycosylated protein with a molecular weight of 20,000 Da as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 21,000 Da as determined by gel fi ltration. Th e optimal pH for the enzyme action was 5.0 and the optimal temperature was 55 °C. Endoxylanase stability was signifi cantly improved in the presence of glycerol and sorbitol. Th e enzyme activity was activated by Mn 2+ and Co 2+ , and it was inhibited by Ag + , Cu 2+ , Fe 3+ , Fe 2+ , and Pb 2+ . Th e substrate specifi city and the product profi le of the enzyme suggested that it was an endoxylanase. Th e enzyme showed a synergism with another endoxylanase from Aspergillus niger B03 in xylan hydrolysis.

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Two methods for increasing b-cyclodextrin yield, achieved with cyclodextrin glucanotransferase from Bacillus megaterium were investigated. A membrane process was performed, allowing a reuse of the enzyme. A process for simultaneous production and isolation of b-cyclodextrin in the presence of complexing agents was conducted. The b-cyclodextrin yield was increased twofold, when the product was precipitated with trichloroethylene or toluene. A change in the product selectivity of cyclodextrin glucanotransferase occurred, resulting in an increase in the relative amount of b-cyclodextrin up to 90% of all cyclodextrins formed. Yield increase was due to the removal of product inhibition and the coupling activity of the enzyme, which limited the full conversion of starch. The isolated cyclodextrin products contained 75-79% b-cyclodextrin, and 4-6% each of a-, and c-cyclodextrins.

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