title: Mass production of rubusoside using a novel stevioside-specific β-glucosidase from Aspergillus aculeatus.
abstract: Rubusoside (R) is a natural sweetener and a solubilizing agent with antiangiogenic and antiallergic properties. However, currently, its production is quite expensive, and therefore, we have investigated nine commercially available glycosidases to optimize an economically viable R-production method. A stevioside (ST)-specific β-glucosidase (SSGase) was selected and purified 7-fold from  Aspergillus aculeatus  Viscozyme L by a two-step column chromatography procedure. The 79 kDa protein was stable from pH 3.0 to pH 7.0 at 50-60 °C. Hydrolysis of ST by SSGase produced R and steviol monoglucosyl ester as determined by (1)H and (13)C nuclear magnetic resonance (NMR). Importantly, SSGase showed higher activity toward ST than other β-linked glucobioses. The optimal conditions for R production were 280 mM ST and 16.6 μL of SSGase at pH 5.1 and 63 °C. This is the first discussion detailing the production of R by enzymatic hydrolysis of ST and is useful for the food additive and pharmaceutical industries.
authors.affiliation: Infection Control Material Research Center, Korea Research Institute of Bioscience and Biotechnology, Jeongeup, Republic of Korea.
authors.forename: Jin-A
authors.initials: JA
authors.lastname: Ko
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kim
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Ryu
authors.forename: Hyung Jae
authors.initials: HJ
authors.lastname: Jeong
authors.forename: Tae-Soon
authors.initials: TS
authors.lastname: Park
authors.forename: Su-Jin
authors.initials: SJ
authors.lastname: Park
authors.forename: Young-Jung
authors.initials: YJ
authors.lastname: Wee
authors.forename: Joong-Su
authors.initials: JS
authors.lastname: Kim
authors.forename: Doman
authors.initials: D
authors.lastname: Kim
authors.forename: Woo Song
authors.initials: WS
authors.lastname: Lee
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D044602:Cellulases / Q000378:metabolism*; D045786:Diterpenes, Kaurane / Q000096:biosynthesis* / Q000378:metabolism*; D005960:Glucosides / Q000096:biosynthesis* / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D013379:Substrate Specificity
chemical_list: D045786:Diterpenes, Kaurane; D005960:Glucosides; C012043:stevioside; D044602:Cellulases; C056177:rubusoside