PURIFICATION AND CHARACTERIZATION OF A (1,4)-BETA-D-ARABINOXYLAN ARABINOFURANOHYDROLASE FROM ASPERGILLUS-AWAMORI

An enzyme able to split off arabinose side-chains from cereal arabinoxylans was isolated from a cell-free culture filtrate of Aspergillus awamori CMI 142717 containing milled oat straw as the carbon source. The enzyme was highly specific for arabinoxylans and, unlike other alpha-L-arabinofuranosidases reported in the literature, did not show any activity towards p-nitrophenyl alpha-L-arabinofuranoside, arabinans and arabinogalactans. This novel enzyme, which can be described as a (1,4)-beta-D-arabinoxylan arabinofuranohydrolase, had a molecular mass of 32 000 Da when determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and a specific activity of 22 units/mg on wheat arabinoxylan.