Department of Microbiology, Bundelkhand University, Jhansi, Uttar Pradesh 284128, India.
Department of Microbiology, Bundelkhand University, Jhansi, Uttar Pradesh 284128, India.
Int J Biol Macromol. 2020 Dec 1;164:3332-3339. doi: 10.1016/j.ijbiomac.2020.08.205. Epub 2020 Aug 29.
Alpha-amylase producing strain KB 2216 was identified as Bacillus velezensis. The growth pattern showed that 72 h is the optimum incubation period of amylase production, which is a stationary period for the strain. By the purification process, maximum alpha-amylase activity was achieved up to 418.25 U/mL at 72 h of incubation, which was purified with 4.74 folds, 4230.32 U/mg specific activity, with 31.35% yield. The strain was found to produce an oligomeric alpha-amylase, namely Amy3. Amy3 was a trimeric macromolecule of 195 kDa with 62, 64, and 66 kDa subunits, as revealed by zymogram and SDS PAGE analyses. Amy3 was highly active at 55 °C and pH 5.5. It had shown the highest stability at pH 5.0-5.5 and between 0 ̊C and 4 ̊C. It did not require any metal cofactors, but it was inhibited by Ag, Hg and Cd divalent cations. Glucose and maltose were shown to be the end products of soluble starch digestion by Amy3. These interesting properties of Amy3 may be useful for many biotechnological applications in the future.
产α-淀粉酶的菌株 KB 2216 被鉴定为解淀粉芽孢杆菌。生长模式表明,72 h 是淀粉酶生产的最佳孵育期,这是菌株的静止期。通过纯化过程,在 72 h 的孵育期内,α-淀粉酶活性达到最大值,为 418.25 U/mL,纯化倍数为 4.74 倍,比活为 4230.32 U/mg,产率为 31.35%。该菌株被发现产生一种寡聚α-淀粉酶,即 Amy3。Amy3 通过酶谱和 SDS PAGE 分析,是一种三聚体的大分子,分子量为 195 kDa,由 62、64 和 66 kDa 的亚基组成。Amy3 在 55°C 和 pH 5.5 下具有很高的活性。它在 pH 5.0-5.5 和 0-4°C 之间表现出最高的稳定性。它不需要任何金属辅因子,但被 Ag、Hg 和 Cd 二价阳离子抑制。葡萄糖和麦芽糖被证明是 Amy3 消化可溶性淀粉的终产物。Amy3 的这些有趣特性可能对未来的许多生物技术应用有用。
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