[Biological conversion of stevioside to steviol by Aspergillus aculeatus and the purification of rebaudioside A].
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%.


CONCLUSIONS
Aspergillus aculeatus enzyme extracts could convert stevioside efficiently and specifically, and we could obtain rebaudioside A and steviol at the same time.
Yingying
Y
Ma
Yuru
Y
Chen
Weina
W
Zhang
Huan
H
Sun
Wenjing
W
Xia
D001230:Aspergillus / Q000378:metabolism*; D001711:Biotransformation; D045786:Diterpenes, Kaurane / Q000302:isolation & purification* / Q000378:metabolism*; D005285:Fermentation; D005960:Glucosides / Q000378:metabolism*
D045786:Diterpenes, Kaurane; D005960:Glucosides; C012043:stevioside; C012042:steviol; C025474:rebaudioside A