Preparation, characterization and application of Aspergillus sp. xylanase immobilized on Eudragit S-100
Preparation, characterization and application of Aspergillus sp. xylanase immobilized on Eudragit S-100
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DOI：
10.1016/s0168-1656(98)00146-1
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发表时间：
1998-12-11
影响因子：
4.1
通讯作者：
Kamat, MY
中科院分区：
文献类型：
--
作者：
Gawande, PV;Kamat, MY
曲霉属(Aspergilla sp.)5号(菌株5)和曲霉属(Aspergillussp.)44号菌株在1%小麦麸皮上产木聚糖酶(分别为34.3和32.7IU·ml~(-1))，纤维素酶含量很低。将木聚糖酶以非共价方式固定化在优拉吉特S-100上进行糖化。该体系对菌株5和菌株44的木聚糖酶活力分别保持了70%和80%的活力。在固定化时，最适活性温度在50-60摄氏度之间扩大，而游离酶的最适活性温度为50摄氏度。固定化时的最适pH没有明显的变化。然而，固定化主要通过降低对失活反应的温度敏感性来提高酶的稳定性。5号木聚糖酶和44号木聚糖酶的K-m值分别从5.6和9.0 mg ml(-1)增加到8.3 mg m l(-1)和7.0 mg m l(-1)。对木聚糖酶进行固定化处理，提高了木聚糖酶和麸皮的糖化效率。两个菌株的固定化木聚糖酶产生的糖分是游离木聚糖酶的三倍。在反复间歇糖化试验中，固定化木聚糖酶重复使用三次，酶活没有损失。(C)1998 Elsevier Science B.V.保留所有权利。
Aspergillus sp. 5 (strain 5) and Aspergillus sp. 44 (strain 44) produced xylanase (34.3 and 32.7 IU ml(-1) respectively) with very low levels of cellulases when grown on 1% wheat bran medium. Xylanase was non-covalently immobilized on Eudragit S-100 for saccharification. The system retained 70 and 80% of strain 5 and strain 44 xylanase activity, respectively. On immobilization, optimum temperature of activity broadened between 50 and 60 degrees C as compared to 50 degrees C in the case of the free enzymes. No significant shift in the pH optima was observed on immobilization. However, immobilization increased enzyme stability mainly by decreasing the temperature sensitivity to the inactivation reaction. The K-m values increased from 5.6 to 8.3 mg ml(-1) for strain 5 xylanase and 7.0 to 9.0 mg ml(-1) for strain 44 xylanase. Enzymatic saccharification of xylan and wheat bran was improved on xylanase immobilization. Immobilized xylanase from both the strains produced three times more sugar as compared to free xylanase. In repeated batch saccharification studies immobilized xylanase was recycled three times without loss of enzyme activity. (C) 1998 Elsevier Science B.V. All rights reserved.