Nigam Vinod K, Arfi Tesnim, Kumar Vishal, Shukla Pratyoosh
Department of Bio-Engineering, Birla Institute of Technology, Mesra, Ranchi, 835215 India.
Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, 124001 India.
Indian J Microbiol. 2017 Jun;57(2):131-138. doi: 10.1007/s12088-017-0645-5. Epub 2017 Mar 25.
Nitrilases are commercial biocatalysts used for the synthesis of plastics, paints, fibers in the chemical industries, pharmaceutical drugs and herbicides for agricultural uses. Nitrilase hydrolyses the nitriles and dinitriles to their corresponding carboxylic acids and ammonia. They have a broad range of substrate specificities as well as enantio-, regio- and chemo-selective properties which make them useful for biotransformation of nitriles to important compounds because of which they are considered as 'Green Catalysts'. Nitriles are widespread in nature and synthesized as a consequence of anthropogenic and biological activities. These are also present in certain plant species and are known to cause environmental pollution. Biotransformation using native organisms as catalysts tends to be insufficient since the enzyme of interest has very low amount in the total cellular protein, rate of reaction is slow along with the instability of enzymes. Therefore, to overcome these limitations, bioengineering offers an alternative approach to alter the properties of enzymes to enhance the applicability and stability. The present review highlights the aspects of producing the recombinant microorganisms and overexpressing the enzyme of interest for the enhanced stability at high temperatures, immobilization techniques, extremes of pH, organic solvents and hydrolysing dintriles to chiral compounds which may enhance the possibilities for creating specific enzymes for biotransformation.
腈水解酶是化学工业中用于合成塑料、涂料、纤维、医药和农用除草剂的商业生物催化剂。腈水解酶将腈和二腈水解为相应的羧酸和氨。它们具有广泛的底物特异性以及对映选择性、区域选择性和化学选择性，这使得它们可用于腈向重要化合物的生物转化，因此被视为“绿色催化剂”。腈在自然界中广泛存在，是人为活动和生物活动的产物。它们也存在于某些植物物种中，并且已知会造成环境污染。使用天然生物体作为催化剂进行生物转化往往不足，因为目标酶在总细胞蛋白中的含量非常低，反应速率缓慢且酶不稳定。因此，为了克服这些限制，生物工程提供了一种替代方法来改变酶的性质，以提高其适用性和稳定性。本综述重点介绍了生产重组微生物和过量表达目标酶以提高高温稳定性、固定化技术、极端pH值、有机溶剂以及将二腈水解为手性化合物等方面，这可能会增加创建用于生物转化的特定酶的可能性。
