title: Production of Rebaudioside A from Stevioside Catalyzed by the Engineered Saccharomyces cerevisiae.
abstract: Rebaudioside A has superior taste quality among the steviol glycosides extracted from Stevia rebaudiana leaves. Given its high purity as a general-purpose sweetener, rebaudioside A has received significant attention and has been widely applied in food and beverages in recent decades. Stevioside is one of the major steviol glycosides and can be converted to rebaudioside A by the uridine-diphosphate dependent glucosyltransferase UGT76G1 in S. rebaudiana. To explore the applicability of and limits in producing rebaudioside A from stevioside through whole-cell biocatalysis, the engineered Saccharomyces cerevisiae expressing UGT76G1, using a newly constructed constitutive expression vector, was used as the whole-cell biocatalyst. Citrate was added to the reaction mixture to allow metabolic regulation when glucose was fed to provide the activated sugar donor UDP-glucose for glycosylation of stevioside in vivo. In an evaluation of the whole-cell reaction parameters involving cell permeability, temperature, pH, citrate and Mg(2+) concentrations, and glucose feeding, production of 1160.5 mg/L rebaudioside A from 2 g/L stevioside was achieved after 48 h without supplementation of extracellular UDP-glucose.
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China. liyan@njtech.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Li
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Chen
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Yan
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Kequan
authors.initials: K
authors.lastname: Chen
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.affiliation: College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, Jiangsu, 211816, China.
authors.forename: Pingkai
authors.initials: P
authors.lastname: Ouyang
mesh_terms: D002384:Catalysis; D045786:Diterpenes, Kaurane / Q000096:biosynthesis* / Q000737:chemistry; D005503:Food Additives / Q000737:chemistry; D005960:Glucosides / Q000737:chemistry; D005964:Glucosyltransferases / Q000096:biosynthesis* / Q000235:genetics; D060847:Metabolic Engineering; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D036625:Stevia / Q000737:chemistry; D013549:Sweetening Agents / Q000737:chemistry; D014530:Uridine Diphosphate / Q000737:chemistry / Q000378:metabolism; D014532:Uridine Diphosphate Glucose / Q000737:chemistry / Q000378:metabolism
chemical_list: D045786:Diterpenes, Kaurane; D005503:Food Additives; D005960:Glucosides; D013549:Sweetening Agents; C012043:stevioside; D014530:Uridine Diphosphate; C025474:rebaudioside A; D005964:Glucosyltransferases; D014532:Uridine Diphosphate Glucose
keywords: Rebaudioside A; Saccharomyces cerevisiae; Stevioside; UDP-glucosyltransferase; Whole-cell biocatalyst