As a prebiotics, lactosucrose plays an important role in maintaining human gastrointestinal homeostasis. In this study, a thermostable enzyme from Arthrobacter sp. 10138 was screened from six β-fructofuranosidase-producing strains for the lactosucrose production and the coding gene was heterologously expressed in Escherichia coli for efficient expression. Recombinant β-fructofuranosidase was purified and biochemically characterized by MALDI-TOFMS spectrometry. The transfructosylation product by this recombinant enzyme was determined to be lactosucrose rather than other oligosaccharides or polysaccharides by HPLC and LC-MS. Efficient extracellular secretion of β-fructofuranosidase was achieved by the optimization of signal peptide and induction conditions. It was found that with the signal peptide torT, the highest extracellular activity reached 111.01 U/mL, which was 38.4-fold higher than that with the OmpA signal peptide. Under the optimal conditions (pH 6.0, temperature 50°C, enzyme amount 40 μg/ml, sucrose 150 g/L and lactose 150 g/L), 109 g/L lactosucrose was produced with a molar conversion ratio of 49.3%. Here the thermostable β-fructofuranosidase from Arthrobacter sp. 10138 can be used for efficient synthesis of lactosucrose, and this provides a good startpoint for the industrial production of lactosucrose in the future.

中文翻译：

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使用节杆菌属的重组热稳定β-果糖呋喃糖苷酶生物催化合成乳糖。10138。

乳糖蔗糖作为益生元，在维持人体胃肠道稳态方面起着重要作用。在这项研究中，节杆菌属的一种热稳定酶。从六个产生β-果糖呋喃糖苷酶的菌株中筛选了10138个乳糖蔗糖的产生，并且编码基因在大肠杆菌中异源表达以有效表达。纯化重组β-果糖呋喃糖苷酶并通过MALDI-TOFMS光谱进行生化表征。通过HPLC和LC-MS确定该重组酶的果糖基化产物为乳糖苷，而不是其他寡糖或多糖。通过优化信号肽和诱导条件，可以实现β-果糖呋喃糖苷酶的高效细胞外分泌。发现信号肽torT 最高的细胞外活性达到111.01 U / mL，比OmpA信号肽高38.4倍。在最佳条件下（pH 6.0，温度50°C，酶量40μg/ ml，蔗糖150 g / L和乳糖150 g / L），产生109 g / L的乳糖酶，摩尔转化率为49.3％。在这里，来自节杆菌属的热稳定的β-果糖呋喃糖苷酶。10138可用于高效合成乳糖，这为将来工业生产乳糖提供了一个很好的起点。在这里，来自节杆菌属的热稳定的β-果糖呋喃糖苷酶。10138可用于高效合成乳糖，这为将来工业生产乳糖提供了一个很好的起点。在这里，来自节杆菌属的热稳定的β-果糖呋喃糖苷酶。10138可用于高效合成乳糖，这为将来工业生产乳糖提供了一个很好的起点。