Multicopper oxidase mutant with improved salt tolerance

Patent metadata

Field	Value
Publication number	US-11008552-B2
Application number	US-201916524382-A
Country	US
Kind code	B2
Filing date	Jul 29, 2019
Priority date	May 24, 2019
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

The present disclosure provides a multicopper oxidase mutant with improved salt tolerance. Threonine at site 317 of wild-type multicopper oxidase WT was mutated to asparagine, leucine at site 386 was mutated to tyrosine, and serine at site 427 was mutated to glutamic acid by site-directed mutagenesis to obtain a mutant T317N-L386Y-S427E. Compared with WT, the tolerance of T317N-L386Y-S427E to 6%, 9%, 12%, 15% and 18% NaCl (W/V) is improved.

First claim

What is claimed is:

1. A multicopper oxidase mutant,
wherein: (a) the multicopper oxidase mutant comprises the amino acid sequence SEQ ID NO:1, or (b) the multicopper oxidase mutant comprises the amino acid sequence SEQ ID NO:1 with residue number 110 mutated to glutamic acid (A110E), and
wherein the multicopper oxidase mutant possesses oxidase enzymatic activity.

2. A method for producing a multicopper oxidase mutant comprising:
inoculating a genetically engineered bacterium transformed with a gene encoding a multicopper oxidase mutant of claim 1 into a medium;
inducing the genetically engineered bacterium to express the gene;
collecting the genetically engineered bacterium;
disrupting the genetically engineered bacterium; and
purifying the multicopper oxidase mutant from the disrupted genetically engineered bacterium.

3. The method according to claim 2 , which further comprises:
adding the purified multicopper oxidase mutant to a food, thereby removing biogenic amines in the food by degradation.

4. The method according to claim 3 , wherein the food comprises soy sauce.

5. The method according to claim 3 , wherein the biogenic amine comprises at least one of tryptamine, phenethylamine, putrescine, cadaverine, histamine, tyramine, spermine and spermidine.

Assignees

• Univ Jiangnan

Inventors

• Fang Fang
• Yang Tao
• Zhou Jingwen
• Chen Jian
• Du Guocheng
• Xu Jie

Classifications

• A23L5/25

  using enzymes · CPC title

• C12Y116/03001

  Ferroxidase (1.16.3.1), i.e. ceruloplasmin · CPC title

• C12N15/52

  Genes encoding for enzymes or proenzymes · CPC title

• C12Y110/03003

  L-ascorbate oxidase (1.10.3.3) · CPC title

• C12Y110/03002

  Laccase (1.10.3.2) · CPC title