Method for bioconversion of mogroside extracts into siamenoside I

Patent metadata

Field	Value
Publication number	US-11180789-B2
Application number	US-201916584216-A
Country	US
Kind code	B2
Filing date	Sep 26, 2019
Priority date	Sep 26, 2019
Publication date	Nov 23, 2021
Grant date	Nov 23, 2021

Abstract

The present invention provides a method for bioconversion of mogroside extracts into siamenoside I, comprising: using (1) DbExg1 protein or (2) a microorganism expressing the DbExg1 protein to contact or to cultivate with the mogroside extracts. The present invention can convert the mogroside extracts into siamenoside I, which has a higher sweetening power and better taste than other mogrosides. The method of the present invention uses a microorganism expressing the responsible enzyme, DbExg1, which was identified as a mediator of mogroside V conversion into siamenoside I in the present invention, so that siamenoside I was preferentially produced. Thus, the use of the method of the present invention provides a feasible approach to produce large quantities of the natural sweetener, siamenoside I, which can then be applied in several industries.

First claim

What is claimed is:

1. A method for bioconversion of mogroside extracts into siamenoside I, comprising:
(1) contacting a Dekkera bruxellensis extracellular β-glucosidase (DbExg1) protein with the mogroside extracts, or
(2) cultivating a microorganism expressing the DbExg1 protein with the mogroside extracts,
thereby converting the mogroside extracts into siamenoside I;
wherein the DbExg1 protein is Dekkera bruxellensis BCRC 21518 extracellular β-glucosidase,
wherein the mogroside extracts comprise mogroside V, and
wherein the DbExg1 protein converts mogroside V to siamenoside I.

2. The method of claim 1 , wherein mogroside V is the main mogroside in the mogroside extracts.

3. The method of claim 1 , wherein the microorganism is Dekkera bruxellensis.

4. The method of claim 1 , wherein the bioconversion is by cultivating the microorganism expressing the DbExg1 protein with the mogroside extracts, wherein the microorganism is a yeast, and wherein the yeast comprises a polynucleotide encoding the DbExg1 protein or comprises a modification to the promoter of the native DbExg1 gene.

5. The method of claim 4 , wherein the yeast is Saccharomyces cerevisiae with a deletion of an extracellular β-glucosidase.

6. The method of claim 1 , wherein the DbExg1 protein is a recombinant DbExg1 protein.

7. The method of claim 1 , wherein the bioconversion is performed at pH 3.0 to 7.0.

8. The method of claim 7 , wherein the bioconversion is performed at pH 5.0 to 7.0.

9. The method of claim 1 , wherein the bioconversion is performed at a temperature ranging from 30 to 60° C.

10. The method of claim 9 , wherein the bioconversion is performed at 50 to 60° C.

Assignees

• Univ Nat Taiwan

Inventors

• Lo Yi-Chen
• Lu Ting-Jang
• Wang Reuben

Classifications

• C12N9/2402 Primary

  hydrolysing O- and S- glycosyl compounds (3.2.1) · CPC title

• C12P19/14

  produced by the action of a carbohydrase {(EC 3.2.x)}, e.g. by alpha-amylase {, e.g. by cellulase, hemicellulase} · CPC title

• C12P33/20 Primary

  containing heterocyclic rings · CPC title