Microbial conversion of sugar acids and means therein

Patent metadata

Field	Value
Publication number	US-9340809-B2
Application number	US-201314062121-A
Country	US
Kind code	B2
Filing date	Oct 24, 2013
Priority date	May 30, 2005
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A DNA molecule comprising a fungal gene encoding an enzyme protein capable of converting L-galactonic acid into L-threo-3-deoxy-hexulosonic acid has been cloned and heterologously expressed. The enzyme is involved in the metabolic conversion of sugar acids, which are present in biological waste material such as sugar beet pulp and other pectin comprising material. A microorganism genetically modified to effectively express said enzyme may be used in fermenting biomaterial to desired end products such as ethanol. Alternatively, microorganisms in which the gene has been inactivated may be used to produce L-galactonic acid, which accumulates when the expression of the gene is prevented.

First claim

The invention claimed is:

1. A method of producing L-galactonic acid, said method comprising:
providing a fungal microorganism having a gene encoding L-galactonic acid dehydratase capable of converting L-galactonic acid into L-threo-3-deoxy-hexulosonic acid, inactivating said gene by preventing its expression or mutation or deletion of said gene or functional part thereof, and
cultivating the obtained genetically modified micro-organism on a material comprising sugar, sugar acid or derivative thereof and recovering the accumulated L-galactonic acid using the obtained genetically modified microorganism for producing the L-galactonic acid.

2. The method of claim 1 , wherein the microorganism is a microorganism which efficiently utilizes D-galacturonic acid.

3. The method of claim 1 , wherein the genetically modified microorganism is cultivated on biomass.

4. The method of claim 1 , wherein the genetically modified microorganism is cultivated on a substrate comprising D-galacturonic acid or another substrate from which L-galactonic acid can be derived, and the accumulated L-galactonic acid is recovered.

5. The method of claim 4 , wherein the genetically modified microorganism is cultivated on a pectin comprising material.

6. The method of claim 1 , wherein the gene is inactivated by deleting the whole gene or functional part thereof.

Assignees

• Valtion Teknillinen
• Teknologian Tutkimuskeskus Vtt Oy

Inventors

• Hilditch Satu
• Penttilä Merja
• Richard Peter

Classifications

• C12P7/58

  Aldonic, ketoaldonic or saccharic acids (uronic acids C12P19/00) · CPC title

• C12P19/02 Primary

  Monosaccharides (2-ketogulonic acid C12P7/60) · CPC title

• Y02P20/52

  using catalysts, e.g. selective catalysts · CPC title

• C12N9/88 Primary

  Lyases (4.) · CPC title