Abstract In the current research, second most abundant renewable polysaccharide chitin is utilized for meaningful purpose. Owing to auspicious features of chitin it is used as a matrix for immobilization of valuable biocatalyst dextranase. Dextranase belongs to hydrolase family and has broad commercial application in different fields. Functionality of dextranase is further improve with the help of its immobilization on chitin by different protocols. Dextranase used in this study was isolated from a thermophilic bacteria Bacillus megaterium KIBGE-IB31 explored from hydrothermal spring. Isolated dextranase was immobilized on chitin by two different methods namely; adsorption and covalent binding. A comparative study was conducted between soluble, adsorbed and covalently cross linked dextranase. It was observed that although, there was slight deviation in characteristics of dextranase after immobilization but there was marked improvement in stability of enzyme after immobilization. The comparative analysis revealed that dextranase immobilized by adsorption was less stable and fails to retained enzyme stability for increase reusability. The adsorption method was improved after treatment of chitin with acid and showed improved stability as well as reusability. However, dextranase immobilized by covalent cross linking displayed highest stability at high temperature along with increase recycling efficiency as compare to enzyme immobilized by adsorption method. Hence, it can be concluded that though chitin is cheap, easily accessible matrix for immobilization of dextranase but still among different protocols of immobilization covalent cross linking was found to be more appropriate in improving enzyme stability and its reusability at industrial scale. Graphic Abstract

中文翻译：

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以甲壳素为基质固定葡聚糖酶不同方案的比较研究

摘要 在目前的研究中，第二丰富的可再生多糖甲壳素被用于有意义的目的。由于几丁质的吉祥特性，它被用作固定有价值的生物催化剂葡聚糖酶的基质。葡聚糖酶属于水解酶家族，在不同领域具有广泛的商业应用。葡聚糖酶的功能在其通过不同方案固定在几丁质上的帮助下得到进一步提高。本研究中使用的葡聚糖酶是从从热液泉中探索的一种嗜热细菌巨大芽孢杆菌 KIBGE-IB31 中分离出来的。分离的葡聚糖酶通过两种不同的方法固定在几丁质上；吸附和共价结合。在可溶性、吸附和共价交联葡聚糖酶之间进行了比较研究。据观察，虽然，固定化后葡聚糖酶的特性略有偏差，但固定化后酶的稳定性明显提高。比较分析表明，通过吸附固定的葡聚糖酶稳定性较差，无法保持酶的稳定性以增加可重复使用性。用酸处理几丁质后，吸附方法得到改进，稳定性和可重复使用性得到改善。然而，与通过吸附法固定的酶相比，通过共价交联固定的葡聚糖酶在高温下表现出最高的稳定性，并提高了回收效率。因此，可以得出结论，虽然甲壳素价格便宜，用于固定葡聚糖酶但仍处于不同固定化方案中的易于获得的基质共价交联被发现更适合于提高酶稳定性及其在工业规模的可重复使用性。图形摘要