Abstract Amylases are one of the main enzymes used in industry for hydrolyzing starch molecules into simple sugar constituents, can be sourced from plants, animals and microorganisms. Starch converting α-amylase has applications in different industrial sectors, and an ongoing research topic is to improve processing conditions leading to enhanced enzymatic activity and lower processing costs. Surprisingly, there are basically no studies regarding the impact of stirring speed on α-amylase activity. In this work, the effect of stirring speed (0, 50, 250, 500, 1000 and 1500 rpm) on the hydrolysis of gelatinized corn starch dispersions (5 g starch dry basis/100 L) by pancreatic α-amylase (0.125 and 0.250 μg/mL) was studied. The analysis of the hydrolysis kinetics curves showed that relatively small stirring speeds had positive effect on the hydrolysis rate. This effect was likely caused by improvements in the mass transfer coefficient by virtue of increased flow velocities. However, the enzyme activity exhibited a negative trend for high stirring speeds. FTIR analysis of α-amylase subjected to stirring indicated that changes in the Amide I secondary structure might be behind the decreased hydrolysis at high stirring speeds. This short communication provides insights for enhancing the bio-conversion of starch by α-amylase via stirring speed mediation.

中文翻译：

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搅拌速度对α-淀粉酶体外活性的影响

摘要 淀粉酶是工业上用于将淀粉分子水解成单糖成分的主要酶之一，可来源于植物、动物和微生物。淀粉转化 α-淀粉酶在不同的工业领域有应用，正在进行的研究课题是改善加工条件，从而提高酶活性和降低加工成本。令人惊讶的是，目前基本没有关于搅拌速度对α-淀粉酶活性影响的研究。在这项工作中，搅拌速度（0、50、250、500、1000 和 1500 rpm）对胰α-淀粉酶（0.125 和 0.250）水解糊化玉米淀粉分散体（5 g 淀粉干基/100 L）的影响μg/mL) 进行了研究。水解动力学曲线分析表明，较小的搅拌速度对水解速率有积极影响。这种效果很可能是由于流速增加导致传质系数的提高。然而，酶活性在高搅拌速度下表现出负面趋势。受到搅拌的 α-淀粉酶的 FTIR 分析表明，酰胺 I 二级结构的变化可能是在高搅拌速度下水解减少的原因。这篇简短的交流为通过搅拌速度介导增强 α-淀粉酶对淀粉的生物转化提供了见解。受到搅拌的 α-淀粉酶的 FTIR 分析表明，酰胺 I 二级结构的变化可能是在高搅拌速度下水解减少的原因。这篇简短的交流为通过搅拌速度介导增强 α-淀粉酶对淀粉的生物转化提供了见解。受到搅拌的 α-淀粉酶的 FTIR 分析表明，酰胺 I 二级结构的变化可能是在高搅拌速度下水解减少的原因。这篇简短的交流为通过搅拌速度介导增强 α-淀粉酶对淀粉的生物转化提供了见解。