A novel cold-active type I pullulanase from a hot-spring metagenome for effective debranching and production of resistant starch.
A novel cold-active type I pullulanase from a hot-spring metagenome for effective debranching and production of resistant starch.
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DOI：
10.1016/j.biortech.2020.124288
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发表时间：
2020-10
影响因子：
11.4
通讯作者：
M. Thakur;Nitish Sharma;A. Rai;Sudhir P. Singh
中科院分区：
文献类型：
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作者：
M. Thakur;Nitish Sharma;A. Rai;Sudhir P. Singh
普鲁兰酶是一种高效的淀粉脱支酶。在这项研究中，从热水生栖息地的宏基因组中鉴定出一种新型I型普鲁兰酶（PulM），其在40 °C温度和pH 6.0至7.0下表现出最佳的脱支活性。在4 °C的低温下检测到超过50%的酶活性，确定其为冷活性I型普鲁兰酶。它能够有效地催化普鲁兰多糖中α-1，6-糖苷键的水解，比活性为177 U mg−1。结果表明，PulM是一种潜在的淀粉脱支生物催化剂，使马铃薯淀粉的表观直链淀粉含量显著增加约80%。脱支淀粉的老化导致抗性淀粉3的形成。抗性淀粉的得率估计约为45%。与天然淀粉相比，抗性淀粉具有更高的结晶度，增强的热稳定性和对α-淀粉酶消化的抗性。
Pullulanase is a potent enzyme for starch debranching. In this study, a novel type I pullulanase (PulM) was identified from the metagenome of a thermal aquatic habitat that exhibits optimal activity of debranching at 40 °C temperature and pH 6.0 to 7.0. More than 50% enzymatic activity was detected at the low temperature of 4 °C, determining it a cold-active type I pullulanase. It was able to efficiently catalyze the hydrolysis of α-1,6-glycosidic linkages in pullulan, with a specific activity of 177 U mg−1. The results determined PulMto be a potential starch debranching biocatalyst, causing a significant increase of about 80% in the apparent amylose content of potato starch. Retrogradation of the debranched starch resulted in the formation of resistant starch 3. The yield of resistant starch was estimated to be about 45%. The resistant starch exhibited higher crystallinity, enhanced heat-stability, and resistance to α-amylase digestion, as compared to native starch.