Optimization of ginsenosides hydrolyzing beta-glucosidase production from Aspergillus niger using response surface methodology.
To optimize ginsenosides hydrolyzing beta-glucosidase production from Aspergillus niger, response surface methodology was carried out in two stages. The Plackett-Burman design was achieved to screen the important variables that influence beta-glucosidase production. Among 10 variables (wheat bran, soybean powder, CaCl(2), ginsenosides, KH(2)PO(4), MgSO(4), polyethylene glycol (PEG), medium volume, inoculum size, and stirring speed), it was found that wheat bran, KH(2)PO(4), and stirring speed had significant effect on beta-glucosidase activity due to very low p-values (p<0.05). Subsequently, wheat bran, KH(2)PO(4), and stirring speed were further optimized using central composite design. The optimal beta-glucosidase production was predicted to be 4650.14 U/ml with the combination of factors (wheat bran, 34.51 g/l; KH(2)PO(4), 1.78 g/l; stirring speed, 161.60 rpm/min). Finally, under optimal fermentation conditions, ginsenoside Rb(1) was converted to Rd and F(2) by A. niger within 10 min. Little compound K was detected at 30 min, and finally F(2) was completely transformed to compound K within 8 h. The putative conversion pathway of Rb(1) by A. niger was Rb(1), Rd, F(2), and compound K.
Hu
Jiang-Ning
JN
Department of Food Science and Technology, College of Agriculture and Biotechnology, Chungnam National University, Daejon 305-764, Republic of Korea.
Zhu
Xue-Mei
XM
Lee
Ki-Teak
KT
Zheng
Yi-Nan
YN
Li
Wei
W
Han
Li-Kun
LK
Fang
Zhe-Ming
ZM
Gu
Li-Juan
LJ
Sun
Bai-Sheng
BS
Wang
Chun-Yan
CY
Sung
Chang-Keun
CK
D001234:Aspergillus niger / Q000187:drug effects* / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media; D003627:Data Interpretation, Statistical; D004353:Drug Evaluation, Preclinical; D036145:Ginsenosides / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013268:Stimulation, Chemical; D014908:Triticum / Q000737:chemistry; D001617:beta-Glucosidase / Q000096:biosynthesis*
D003470:Culture Media; D036145:Ginsenosides; C442759:ginsenoside Rb1; D001617:beta-Glucosidase