The Cel genes from Bacillus licheniformis MSB03 were cloned and expressed to investigate binding ability on clay minerals and sea sand at pH ranging 3 to 9. FTIR analysis has been done to characterize bound enzymes on clay minerals. Subsequent, surveying of NCBI database for extracellular enzymes of soil bacteria was carried out. Among the five cloned Cel enzymes assayed for binding to clay minerals, only Cel5H enzyme had the binding ability. Enzyme Cel5H exhibited highest binding to montmorillonite followed by kaolinite and sea sand. Interestingly, Cel5H had higher pI value of 9.24 than other proteins (5.2-5.7). Cel5H binding to montmorillonite was shown to be negatively affected below pH 3 and above pH 9. Infrared absorption spectra of the Cel5H-montmorillonite complexes showed distinct peaks for clay minerals and bound proteins. Furthermore, database survey of soil bacterial extracellular enzymes revealed that Bacillus species enzymes had higher pI than other soil bacterial enzymes.

中文翻译：

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克隆的Cel酶在与该酶的pI相关的粘土矿物上的结合以及针对pI的土壤细菌纤维素酶数据库调查。

克隆并表达了地衣芽孢杆菌MSB03的Cel基因，以研究在pH范围为3至9的情况下与粘土矿物和海沙的结合能力。已经进行了FTIR分析以表征与粘土矿物结合的酶。随后，对NCBI数据库中土壤细菌的细胞外酶进行了调查。在测定的五种克隆的Cel酶与粘土矿物质的结合中，只有Cel5H酶具有结合能力。酶Cel5H与蒙脱石的结合力最高，其次是高岭石和海沙。有趣的是，Cel5H的pI值比其他蛋白（5.2-5.7）高9.24。在低于pH 3和高于pH 9的情况下，Cel5H与蒙脱石的结合受到负面影响。Cel5H-蒙脱石复合物的红外吸收光谱显示出粘土矿物质和结合蛋白的明显峰。此外，