The present study deals with the immobilization of cellulase produced from our isolated fungus Aspergillus niger ISSFR-019 on different matrices of which chitosan beads has been found to be the most suitable one. The optimization of the amount of cellulase, amount of beads, temperature and amount of glutaraldehyde used as a cross-linking agent for the procurement of maximum immobilization efficiency has been done on the basis of statistical approach BBD (Box-Behnken Design). Cellulase is found to be successfully immobilized on the chitosan bead surface, with 94.2% efficiency and immobilization yield is found to be 54.1% after statistical optimization. Significant enzymatic activity is recorded after 12 cycles of reuse of the beads. The kinetic study revealed that the Michael’s Menten constant (K_m) is found to be 1.3 mM and 2 mM for free enzyme and immobilized enzyme respectively, the higher Km value for immobilized enzyme indicated conformational change in the enzyme that altered the accessibility of substrate towards the active site of the enzyme. The V_max is found to be 2.7 and 4.4 U/mg-1 respectively for the immobilized and free enzyme. Fourier Transform Infrared Spectroscopy studies revealed the change in absorbance of functional groups when the enzyme is bound to chitosan beads.

中文翻译：

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真菌纤维素酶在壳聚糖微球上的固定及其响应面方法的优化

本研究涉及将我们分离出的真菌黑曲霉ISSFR-019产生的纤维素酶固定在不同的基质上，发现壳聚糖珠是最合适的。纤维素酶的量，珠子的量，温度和用作交联剂的戊二醛的量的优化，以获取最大的固定效率，是基于统计方法BBD（Box-Behnken设计）进行的。经统计优化后，发现纤维素酶已成功固定在壳聚糖微珠表面，效率为94.2％，固定产率为54.1％。磁珠再利用12个循环后，记录到显着的酶活性。动力学研究表明，迈克尔门腾常数（K _m）对于游离酶和固定化酶而言分别为1.3mM和2mM，固定化酶的较高Km值表明酶的构象变化，这改变了底物对酶活性位点的可及性。对于固定的和游离的酶，发现V _max分别为2.7和4.4U / mg-1。傅里叶变换红外光谱研究表明，当酶与壳聚糖微珠结合时，官能团的吸光度会发生变化。