脱乙酰壳聚糖固定化宇佐美曲霉木聚糖酶及固定化酶的性质和应用(英文)

Immobilization of Aspergillus usamii Xylanase on Chitosan, Properties and Application of the Immobilized Enzyme

研究壳聚糖吸附和戊二醛交联对木聚糖酶固定化条件 .将酶液加入到经醋酸溶液处理过的脱乙酰壳聚糖的pH 4 8的悬液中 ,加入浓度为 0 3%～ 0 4 %的戊二醛溶液 ,室温下 ,8h后得到固定化酶 .固定化酶的半失活温度比游离酶高 ,由 5 1℃升至 71℃ ,Km 值由游离酶的 1 2mg ml增加到1 5mg ml ,最适反应温度也由 5 5℃增加到 71℃ ,而最适反应pH由 4 6下降到 3 8.该固定化木聚糖酶可用于制造低聚木糖 .经过 10次连续应用实验后 ,该固定化酶的活力保持 81%

Xylanase was adsorbed on chitosan and crosslinked with glutaraldehyde. The immobilization conditions were investigated. The enzyme was added to the pH 4.8 suspension solution of 10 g chitosan treated by acetic acid solution. Glutaraldehyde concentration 0.3%～0.4% were used and the immobilized xylanase was obtained after 8 hours at room temperature. In comparison with the free enzyme, the temperature for lost of half activity (t 1/2) of the immobilized enzyme was increased from 51℃ to 71℃. The K m value of immobilized enzyme was increased from 1.2 mg/ml to 1.5 mg/ml and the optimum temperature and optimum pH were shifted from 55℃ to 71℃ and from 4.6 to 3.8,respectively. The immobilized xylanases have been used for preparation of the xylo-oligosaccahride. The immobilized enzyme activity retention were about 81%, after ten times continuing hydrolysing tests.