Galactosidases, ubiquitous in nature, are complex carbohydrate-active enzymes and find extensive applications in food, pharma, and biotechnology industries. The present study deals with the production of galactosidases from fungi by solid-state fermentation. Fifteen fungi were screened and Aspergillus awamori (MTCC 548), exhibited the highest α and β-galactosidase activities of 75.11±0.29 U/g and 155.34±1.26 U/g, respectively. 30 g of wheat bran substituted with 6% defatted soy flour, at 28°C, pH 5.0 for 120 h, was established as the optimum production conditions by one-factor approach. The enzyme was purified to homogeneity with an apparent mass of 118 ± 2 kDa by ammonium sulfate precipitation (50-80%), ion exchange and hydrophobic interaction chromatography. Specific activities for α and β-galactosidase were 22 and 74 U/mg, respectively. Optimum temperature and pH ranges for enzyme activities were 55-60 °C, 5.0-5.5, respectively. The thermal inactivation mid-point was 65 °C. The purified enzyme not only exhibited α and β-galactosidase activities, but also exhibited β-xylosidase and β-glucosidase activities, indicating the enzyme has broad substrate specificity. Sequence analysis by in-gel digestion and tandem mass spectrometry (MS/MS) revealed that the enzyme was a probable β-galactosidase A, belonging to glycoside hydrolase 35 family, and is being reported for the first time.

中文翻译：

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泡盛曲霉新的GH家族35半乳糖苷酶的纯化，鉴定和特异性。

半乳糖苷酶本质上无处不在，是复杂的碳水化合物活性酶，在食品，制药和生物技术行业中得到广泛应用。本研究涉及通过固态发酵从真菌生产半乳糖苷酶。筛选了15种真菌，泡盛曲霉（MTCC 548）分别具有最高的α和β-半乳糖苷酶活性，分别为75.11±0.29 U / g和155.34±1.26 U / g。通过一因素法，将30 g麦麸用6％脱脂大豆粉替代，在28°C，pH 5.0下，将120 h作为最佳生产条件。通过硫酸铵沉淀（50-80％），离子交换和疏水相互作用色谱法将酶纯化至表观质量为118±2 kDa的均质。α和β-半乳糖苷酶的比活性分别为22和74 U / mg。酶活性的最佳温度和pH范围分别为55-60°C，5.0-5.5。热失活的中点是65℃。纯化的酶不仅具有α和β-半乳糖苷酶活性，而且还具有β-木糖苷酶和β-葡萄糖苷酶活性，表明该酶具有广泛的底物特异性。通过凝胶内消化和串联质谱（MS / MS）进行的序列分析显示，该酶是可能的β-半乳糖苷酶A，属于糖苷水解酶35家族，并且是首次报道。表明该酶具有广泛的底物特异性。通过凝胶内消化和串联质谱（MS / MS）进行的序列分析显示，该酶是可能的β-半乳糖苷酶A，属于糖苷水解酶35家族，并且是首次报道。表明该酶具有广泛的底物特异性。通过凝胶内消化和串联质谱（MS / MS）进行的序列分析表明，该酶是可能的β-半乳糖苷酶A，属于糖苷水解酶35家族，并且是首次报道。