棘孢曲霉转化甜菊糖为甜菊醇及纯化莱鲍迪苷A

Biological conversion of stevioside to steviol by Aspergillus aculeatus and the purification of rebaudioside A

摘要:

摘要:【目的】本工作对棘孢曲霉固体发酵抽提酶液转化甜菊糖进行了研究，并对转化产物进行鉴定及纯化分析。【方法】用高效液相色谱、液质联用及红外光谱等方法对转化新产物进行鉴定，对上清液中莱鲍迪苷A(RA)成分进行纯化。【结果】棘孢曲霉酶液在10 h内对甜菊糖中的甜菊苷(SS)、莱鲍迪苷C(RC)进行高效特异性转化，以沉淀的形式析出的转化产物经鉴定为甜菊醇，转化率高达98.0%，分离提纯后纯度为95.2%，回收率达84.0%．由于甜菊醇的沉淀分离，留在溶液中的RA更易被纯化。RA通过树脂吸附分离 的回收率为80.5%．【结论】棘孢曲霉酶液对甜菊糖的一次转化可以同时得到甜菊醇和莱鲍迪苷A两种产品，是一种经济高效的工艺。

关键词:关键词:甜菊糖，棘孢曲霉，生物转化，莱鲍迪苷A，甜菊醇

Abstract:

Abstract:［Objective］ The purpose of this research was to apply Aspergillus aculeatus solid fermentation extracts to convert stevioside and rebaudioside C，followed by identifying and purifying the new conversion product．［Methods］The product was identified by high performance liquid chromatography，chromatography-mass spectrometry and Infrared spectrum．The new product and rebaudioside A exited in the supernatant were purified by alcohol and macroporous resin．［Results］The Aspergillus aculeatus enzyme extracts could convert the stevioside and rebaudioside C to the new product within 10 hours． The conversion rate was 98.0% in 24 hours．The conversion product existed in deposit was identified as steviol．The purity and recovery percent of steviol were 95.2% and 84.0% respectively．Because stevioside could occur to deposit，the rebaudioside A existed in supernatant was purified easily． We used the resin chromatography to purify RA and the recovery could reach 80.5%．［Conclusion］Aspergillus aculeatus enzyme extracts could convert stevioside efficiently and specifically，and we could obtain rebaudioside A and steviol at the same time．

Key words:Keywords: stevioside，Aspergillus aculeatus，bioconvert，rebaudioside A，steviol