一种嗜酸双孢霉 MEY-1 菌株的α-半乳糖苷酶与β-甘露聚糖酶具有协同作用。
An alpha-galactosidase from an acidophilic Bispora sp. MEY-1 strain acts synergistically with beta-mannanase.
机构信息
Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
出版信息
Bioresour Technol. 2010 Nov;101(21):8376-82. doi: 10.1016/j.biortech.2010.06.045. Epub 2010 Jun 29.
An alpha-galactosidase gene (AgalB) was cloned from the acidophilic fungus Bispora sp. MEY-1 and expressed in Pichia pastoris. The deduced amino acid sequence showed highest identity (35%) to the alpha-galactosidase from Penicillium simplicissimum, belonging to the glycosyl hydrolase family 27. The purified recombinant alpha-galactosidase (r-AgalB) exhibited optimal activity at pH 3.5 and 55 degrees C, was stable at pH 2.2-8.0, and showed higher hydrolytic activity towards galactomannan polysaccharides (guar gum and locust bean gum) than toward small galacto-oligosaccharides (melibiose, raffinose and stachyose). A synergistic (3-fold) increase in guar gum hydrolysis was observed when beta-mannanase Man5A from Bispora sp. MEY-1 and r-AgalB were combined. Further, an increase in the reaction time from 5h to 12h or increase of the temperature from 37 degrees C to 55 degrees C enhanced guar gum degradation by the enzyme combination. These properties make r-AgalB a good candidate for extensive application in the pulp/paper, food, and feed industries.
从嗜酸真菌 Bispora sp. MEY-1 中克隆了一种α-半乳糖苷酶基因（AgalB），并在毕赤酵母中表达。推导的氨基酸序列与 Penicillium simplicissimum 的α-半乳糖苷酶具有最高的同源性（35%），属于糖苷水解酶家族 27。纯化的重组α-半乳糖苷酶（r-AgalB）在 pH3.5 和 55°C 下表现出最佳活性，在 pH2.2-8.0 下稳定，对半乳甘露聚糖多糖（瓜尔胶和刺槐豆胶）的水解活性高于对小半乳糖寡糖（棉子糖、水苏糖和蜜二糖）。当将 Bispora sp. MEY-1 的β-甘露聚糖酶 Man5A 和 r-AgalB 组合使用时，瓜尔胶的水解活性增加了 3 倍（协同作用）。此外，将反应时间从 5 小时延长至 12 小时或将温度从 37°C 升高至 55°C，均可增强酶混合物对瓜尔胶的降解作用。这些特性使得 r-AgalB 成为在制浆/造纸、食品和饲料工业中广泛应用的良好候选酶。
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