Disclosed is a steviol glycoside referred to as rebaudioside D2. Rebaudioside D2 has five β-D-glucosyl units connected to the aglycone steviol. Also disclosed are methods for producing rebaudioside D2, a UDP-glycosyltransferase fusion enzyme, and methods for producing rebaudioside D and rebaudioside E.

Disclosed are steviol glycosides referred to as rebaudioside V and rebaudioside W. Also disclosed are methods for producing rebaudioside M (Reb M), rebausoside G (Reb G), rebaudioside KA (Reb KA), rebaudioside V (Reb V) and rebaudioside (Reb W).

The disclosure discloses a method for efficient biosynthesis of Reb D by glycosyltransferase, belonging to the field of biocatalytic synthesis. According to the disclosure, a glycosyltransferase having an activity to catalyze synthesis of Reb D from Reb A is obtained, and a mutant YojK-I241T/G327N with high catalytic activity is obtained through directed evolution. The glycosyltransferase mutant YojK-I241T/G327N and a sucrose synthase AtSuSy derived from Arabidopsis thaliana are used for constructing a coupling reaction to realize efficient catalytic synthesis of Reb D with Reb A as a substrate. The reaction is carried out by using 19.32 g/L (20 mmol/L) of Reb A as the substrate for 15 h to efficiently synthesize 20.59 g/L of Reb D, and the yield of Reb D reaches 91.29%, which provides an efficient and green new pathway for production of Reb D.

An isolated sucrose synthase peptide. Also, a method of preparing ADPglucose by incubating the isolated sucrose synthase peptide with ADP in suitable conditions and then isolating and purifying the ADPG produced. Also, an assay kit for the spectrophotometric, fluorimetric or amperometric determination of sucrose, which kit includes the isolated sucrose synthase peptide. Also, a method of producing a transgenic plant that overexpresses sucrose synthase by inserting a genetic construct containing a DNA fragment that encodes the sucrose synthase peptide into a vector and transferring to a plant genome, and a transgenic plant obtained thereby.

The present invention relates to the production of steviol glycoside rebaudiosides D4, WB1 and WB2 and the production of rebaudioside M from Reb D4.

The present invention relates to the production of steviol glycoside rebaudiosides D4, WB1 and WB2 and the production of rebaudioside M from Reb D4.

Disclosed are steviol glycosides referred to as rebaudioside V and rebaudioside W. Also disclosed are methods for producing rebaudioside M (Reb M), rebausoside G (Reb G), rebaudioside KA (Reb KA), rebaudioside V (Reb V) and rebaudioside (Reb W).

Disclosed is a steviol glycoside referred to as rebaudioside D3. Rebaudioside D3 has five β-D-glucosyl units connected to the aglycone steviol. Also disclosed are methods for producing rebaudioside D3, a UDP-glycosyltransferase fusion enzyme, and methods for producing rebaudioside D and rebaudioside E.

The present invention relates, at least in part, to the production of steviol glycoside rebaudioside I through the use of variant UGT enzymes having activity to transfer a glucosyl group from UDP-glucose to rebaudioside A to produce rebaudioside I.

Disclosed are steviol glycosides referred to as rebaudioside V and rebaudioside W. Also disclosed are methods for producing rebaudioside M (Reb M), rebausoside G (Reb G), rebaudioside KA (Reb KA), rebaudioside V (Reb V) and rebaudioside (Reb W).