PURIFICATION AND CHARACTERIZATION OF 3 ALPHA-ARABINOSIDASES FROM ASPERGILLUS-TERREUS

Three alpha-arabinosidases were purified from a culture filtrate of As pergillus terreus VTT-D-82209 grown on sugar beet extraction waste as carbon source. The isoelectric points were 7.5, 8.3 and 8.5, and the m olecular masses as determined by SDS-PAGE were 39, 59 and 59 kDa, resp ectively. The optimum pH was 3.5-4.5 for all three alpha-arabinosidase s. The pI 8.5 enzyme was more stable at higher pH and temperature than the other two. All three alpha-arabinosidases were able to hydrolyze p-nitrophenyl-alpha-L-arabinofuranoside, oat spelt arabinoglucuronoxyl an, rye flour arabinoxylan and rye flour. About 80% of the total arabi nose of arabinoglucuronoxylan isolated from softwood kraft pulp was hy drolyzed with all three enzymes, but the hydrolysis yield of arabinose from arabinoglucuronoxylan isolated from bleached pulp was low. The a mount of arabinose released did not significantly increase in simultan eous hydrolysis with xylanase.