title: Characterization of a novel steviol-producing β-glucosidase from Penicillium decumbens and optimal production of the steviol.
abstract: This study aimed to develop an economically viable enzyme for the optimal production of steviol (S) from stevioside (ST). Of 9 commercially available glycosidases tested, S-producing β-glucosidase (SPGase) was selected and purified 74-fold from Penicillium decumbens naringinase by a three-step column chromatography procedure. The 121-kDa protein was stable at pH 2.3-6.0 and at 40-60 °C. Hydrolysis of ST by SPGase produced rubusoside (R), steviolbioside (SteB), steviol mono-glucoside (SMG), and S, as determined by HPLC, HPLC-MS, and (1)H- and (13)C-nuclear magnetic resonance. SPGase showed higher activity toward steviol mono-glucosyl ester, ST, R, and SMG than other β-linked glucobioses. The optimal conditions for S production (30 mM, 64 % yield) were 47 mM ST and 43 μl of SPGase at pH 4.0 and 55 °C. This is the first report detailing the production of S from ST hydrolysis by a novel β-glucosidase, which may be useful for the pharmaceutical and agricultural areas.
authors.affiliation: Infection Control Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, 580-185, Korea.
authors.forename: Jin-A
authors.initials: JA
authors.lastname: Ko
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Ryu
authors.forename: Hyun-Jun
authors.initials: HJ
authors.lastname: Kwon
authors.forename: Hyung Jae
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Cha Young
authors.initials: CY
authors.lastname: Kim
authors.forename: Young-Jung
authors.initials: YJ
authors.lastname: Wee
authors.forename: Doman
authors.initials: D
authors.lastname: Kim
authors.forename: Woo Song
authors.initials: WS
authors.lastname: Lee
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
mesh_terms: D045786:Diterpenes, Kaurane / Q000096:biosynthesis* / Q000378:metabolism; D004795:Enzyme Stability; D005656:Fungal Proteins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism; D007700:Kinetics; D010407:Penicillium / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity; D001617:beta-Glucosidase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D045786:Diterpenes, Kaurane; D005656:Fungal Proteins; D005960:Glucosides; C012043:stevioside; C012042:steviol; D001617:beta-Glucosidase