黑曲霉A.niger 6640生物转化制备蔗果低聚糖

Preparation of Frucooligosaccharides via Biotransformation by Aspergillus niger 6640

优化了黑曲霉A.niger 6640发酵制备蔗果低聚糖的发酵条件,研究了A.niger6640中β-呋喃果糖苷转移酶(β-Ffase)的性质,用阴离子柱DEAE Sepharose CL-6B对β-Ffase进行了分离纯化,用SDS-PAGE电泳初步分析了β-Ffase的分子质量.结果表明:A.niger 6640发酵制备FOS的最佳p H值为7.6、最佳发酵时间为40 h、最佳发酵温度为33℃、最佳蔗糖质量分数为40%;在磷酸氢二钠-柠檬酸缓冲液中,采用真空干燥工艺从A.niger 6640中制得的β-Ffase的催化反应的最佳p H值为6.5、最佳反应时间为16 h、最适酶用量为0.19 g;分离纯化得到的β-Ffase的分子质量约为75 ku.

In this paper,the preparation conditions of fructooligosaccharides（ FOS） via the biotransformation by Aspergillus niger 6640（ A. niger 6640） were optimized,and the properties of crude enzyme of β-Ffase from A. niger 6640 were investigated. Then,β-Ffase was isolated and purified by using an anion column of DEAE Sepharose CL-6B,and its molecular mass was preliminarily measured by means of SDS-PAGE electrophoresis. The results show that（ 1） the optimal conditions for FOS preparation should be controlled at a p H value of 7. 6,a fermentation time of 40 h,a fermentation temperature of 33 ℃ and a sucrose mass fraction of 40%;（ 2） in the buffer of Na2HPO4-citric acid for the biotransformation using vacuum-dried β-Ffase,the optimal conditions are determined as p H 6. 5,a reaction time of 16 h and a β-Ffase dosage of 0. 19 g; and（ 3） the molecular mass of β-Ffase after isolation and purification is about 75 ku.