Lekakarn Hataikarn, Bunterngsook Benjarat, Pajongpakdeekul Nonthaya, Prongjit Daran, Champreda Verawat
Department of Biotechnology, Faculty of Science and Technology, Thammasat University, Rangsit Campus, Patumthani, 12120 Thailand.
Enzyme Technology Research Team, Biorefinery Technology and Bioproduct Research Group, National Center for Genetic Engineering and Biotechnology, 113 Thailand Science Park, Pahonyothin Road, Khlong Luang, Patumthani 12120 Thailand.
3 Biotech. 2022 Jun;12(6):134. doi: 10.1007/s13205-022-03188-1. Epub 2022 May 23.
Maltooligosaccharide-forming amylases (MFAses) are promising enzymes for a variety of industrial applications. In this study, a maltooligosaccharide-forming amylase (BkAmy) isolated from HL12 was first heterologous expressed and characterized. According to structural-sequence alignment, BkAmy contained seven conserved regions which are the signature of a novel GH13 subfamily. The gene was expressed in KM71 as an extracellular protein with a volumetric activity of 3.38 U/mL culture medium after 72 h induction by 3% (w/v) of methanol. The recombinant BkAmy migrated as a single protein band with an expected size approximately of 55 kDa. BkAmy exhibited the highest catalytic activity on soluble starch with a specific activity of 42.2 U/mg at 40 °C, pH 7.0. The enzyme exhibited 65% relative activity at 30 °C, indicating its advantage on application at moderate reaction temperature desirable for energy saving and reduction of side unwanted reactions. The enzyme exhibited a specific cleavage pattern by releasing maltose (G2), maltotriose (G3) and maltotetraose (G4) from cassava starch with the highest yield of 363 mg/g substrate equivalent to 36% conversion using 40 U/g substrate at 60 min. The work demonstrates the potential of this enzyme on maltooligosaccharide production from starch to create high value-added products in starch processing industries.
The online version contains supplementary material available at 10.1007/s13205-022-03188-1.
形成麦芽低聚糖的淀粉酶（MFAses）是用于各种工业应用的有前景的酶。在本研究中，首先对从HL12中分离出的一种形成麦芽低聚糖的淀粉酶（BkAmy）进行了异源表达和表征。根据结构序列比对，BkAmy包含七个保守区域，这是一个新的GH13亚家族的特征。该基因在KM71中表达，作为一种细胞外蛋白，在3%（w/v）甲醇诱导72小时后，体积活性为3.38 U/mL培养基。重组BkAmy迁移为一条单一蛋白带，预期大小约为55 kDa。BkAmy对可溶性淀粉表现出最高的催化活性，在40°C、pH 7.0时比活性为42.2 U/mg。该酶在30°C时表现出65%的相对活性，表明其在中等反应温度下应用的优势，有利于节能和减少不必要的副反应。该酶通过从木薯淀粉中释放麦芽糖（G2）、麦芽三糖（G3）和麦芽四糖（G4）表现出特定的切割模式，在60分钟时使用40 U/g底物，最高产量为363 mg/g底物，相当于36%的转化率。这项工作证明了这种酶在从淀粉生产麦芽低聚糖以在淀粉加工行业中创造高附加值产品方面的潜力。
在线版本包含可在10.1007/s13205-022-03188-1获取的补充材料。
