Fructooligosaccharides (FOS) have widely used for the manufacture of low-calorie and functional foods, because they can inhibit intestinal pathogenic microorganism growth and increase the absorption of Ca2+ and Mg2+. In this study, the novel fructosyltransferase (FTase) from Aspergillus oryzae strain S719 was successfully purified and characterized. The specific activity of the final purified material was 4200 mg-1 with purification ratio of 66 times and yield of 26%. The molecular weight of FTase of A. oryzae S719 was around 95 kDa by SDS-PAGE, which was identified as a type of FTase by Mass Spectrometry (MS). The purified FTase had optimum temperature and pH of 55 °C and 6.0, respectively. The FTase showed to be stable with more than 80% of its original activity at room temperature after 12 h and maintaining activity above 90% at pH 4.0-11.0. The Km and kcat values of the FTase were 310 mmol L-1 and 2.0 × 103 min-1, respectively. The FTase was activated by 5 mmol L-1 Mg2+ and 10 mmol L-1 Na+ (relative activity of 116 and 114%, respectively), indicating that the enzyme was Mg2+ and Na+ dependent. About 64% of FOS was obtained by the purified FTase under 500 g L-1 sucrose within 4 h of reaction time, which was the shortest reaction time to be reported regarding the purified enzyme production of FOS. Together, these results indicated that the FTase of A. oryzae S719 is an excellent candidate for the industrial production of FOS.

中文翻译：

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米曲霉S719中具有高FOS转果糖基化活性的新型果糖基转移酶的纯化和生化特性。

低聚果糖（FOS）已被广泛用于制造低热量和功能性食品，因为它们可以抑制肠道病原微生物的生长并增加Ca2 +和Mg2 +的吸收。在这项研究中，成功​​地纯化和鉴定了米曲霉菌株S719的新型果糖基转移酶（FTase）。最终纯化的物质的比活性为4200 mg-1，纯化率为66倍，产率为26％。通过SDS-PAGE，米曲霉S719的FTase的分子量为约95kDa，其通过质谱（MS）被鉴定为FTase的一种。纯化的FTase的最佳温度和pH分别为55°C和6.0。FTase显示稳定，在12小时后于室温下具有超过其原始活性的80％，并在pH 4.0-11.0下保持90％以上的活性。FTase的Km和kcat值分别为310 mmol L-1和2.0×103 min-1。FTase被5 mmol L-1 Mg2 +和10 mmol L-1 Na +激活（相对活性分别为116和114％），表明该酶具有Mg2 +和Na +依赖性。在500 g L-1蔗糖中，在反应时间内4小时内，通过纯化的FTase获得约64％的FOS，这是有关FOS纯化酶生产的最短反应时间。总之，这些结果表明米曲霉S719的FTase是工业生产FOS的极好的候选者。在反应时间内4小时内，在500 g L-1蔗糖下，纯化的FTase可获得约64％的FOS，这是有关FOS纯化酶生产的最短反应时间。总之，这些结果表明米曲霉S719的FTase是工业生产FOS的极好的候选者。在反应时间内4小时内，在500 g L-1蔗糖下，纯化的FTase可获得约64％的FOS，这是有关FOS纯化酶生产的最短反应时间。总之，这些结果表明米曲霉S719的FTase是工业生产FOS的极好的候选者。