Abstract：
α-Amylases are essential biocatalysts representing a billion-dollar market with significant long-term global demand. They have varied applications ranging from detergent, textile, and food sectors such as bakery to, more recently, biofuel industries. Microbial α-amylases have distinct advantages over their plant and animal counterparts owing to generally good activities and better stability at temperature and pH extremes. With the scope of applications expanding, the need for new and improved α-amylases is ever-growing. However, scaling up microbial α-amylase technology from the laboratory to industry for practical applications is impeded by several issues, ranging from mass transfer limitations, low enzyme yields, and energy-intensive product recovery that adds to high production costs. This review highlights the major challenges and prospects for the production of microbial α-amylases, considering the various avenues of industrial bioprocessing such as culture-independent approaches, nutrient optimization, bioreactor operations with design improvements, and product down-streaming approaches towards developing efficient α-amylases with high activity and recyclability. Since the sequence and structure of the enzyme play a crucial role in modulating its functional properties, we have also tried to analyze the structural composition of microbial α-amylase as a guide to its thermodynamic properties to identify the areas that can be targeted for enhancing the catalytic activity and thermostability of the enzyme through varied immobilization or selective enzyme engineering approaches. Also, the utilization of inexpensive and renewable substrates for enzyme production to isolate α-amylases with non-conventional applications has been briefly discussed.
摘要：
α-淀粉酶是代表具有显著长期全球需求的十亿美元市场的必需生物催化剂。他们有各种各样的应用范围从洗涤剂，纺织品,和食品行业，如面包店，最近,生物燃料工业。微生物α-淀粉酶由于在温度和pH极限下通常具有良好的活性和更好的稳定性而优于其植物和动物对应物。随着应用范围的扩大,对新的和改进的α-淀粉酶的需求不断增长。然而,微生物α-淀粉酶技术从实验室推广到工业实际应用受到几个问题的阻碍，从传质限制，酶产量低，和能源密集型产品回收，增加了高生产成本。这篇综述强调了微生物α-淀粉酶生产的主要挑战和前景，考虑到工业生物加工的各种途径，如独立于文化的方法，营养优化，设计改进的生物反应器操作，和产品下游方法，以开发具有高活性和可回收性的高效α-淀粉酶。由于酶的序列和结构在调节其功能特性中起着至关重要的作用，我们还试图分析微生物α-淀粉酶的结构组成，作为其热力学性质的指导，以确定可以通过各种固定化或选择性酶工程方法来增强酶的催化活性和热稳定性的区域。此外，已经简要讨论了利用廉价和可再生的底物来生产酶以非常规应用分离α-淀粉酶。
