Genetically transformed microorganisms with simultaneous enhancement of reduction potential and reductive enzyme activities for biomass fermentation

• US 8,741,652 B2
• Filed: 02/16/2009
• Issued: 06/03/2014
• Est. Priority Date: 02/20/2008
• Status: Expired due to Fees

• Current Assignee: Nagarjuna Fertilizers And Chemicals Limited
• Original Assignee: Nagarjuna Fertilizers And Chemicals Limited
• Inventors: Siddavattam, Siddavattam Dayananda, Choudary, Doddala Doddala Anitha, Venkatanarayanan, Karthikeyan Karthikeyan
• Primary Examiner(s): VOGEL, NANCY TREPTOW
• Application Number:
  US12/918,534
• Publication Number:
  US 20110152511A1
• Time in Patent Office: 1,933 Days
• Field of Search: None
• US Class Current: 435/471
• CPC Class Codes: C12N 9/0006 acting on CH-OH groups as donors (1.1)
• CPC Class Codes: C12N 9/0008 acting on the aldehyde or oxo group of donors (1.2)

Abstract

The present invention describes the genetic engineering of production microorganisms used in biotechnology to improve their properties so that they produce industrially useful products more efficiently from fermentable sugars derived from biomass. The engineered microorganisms endowed with functional coupling of oxidation and reduction of substrates by dehydrogenases requiring pyridine nucleotides (NAD/NADH) result in simultaneous enhancement of reduction potential enzyme activity involving the transfer of electrons. In particular, this invention relates to the construction of an excisable gene expression cassette for expression of two different dehydrogenases leading to enhanced production of ethanol.

Claims

1. A gene cassette construction comprising a Triosephosphate dehydrogenase (TDH3) gene from Saccharomyces cerevisiae driven by a first Saccharomyces cerevisiae ADH1 promoter followed by an Alcohol dehydrogenase (ADH1) gene from Saccharomyces cerevisiae driven by a second Saccharomyces cerevisiae ADH1 promoter.

2. The gene cassette construction according to claim 1, wherein the genes are positioned in tandem.

3. The gene cassette construction according to claim 1, wherein the gene cassette is multimerized.

4. A yeast host strain comprising the gene cassette construction according to claim 1, wherein the genes are introduced into host yeast strains either as episomal or chromosomal integrates.

5. A yeast host strain comprising the gene cassette construction according to claim 1, wherein the gene cassette is introduced into host yeast strains for the production of ethanol, lactic acid and other fermentative products.

6. A yeast host strain comprising the gene cassette construction according to claim 1, wherein the genes are introduced into Saccharomyces cerevisiae haploid, diploid or polyploid strains.

7. A method comprising:

transforming any host yeast strain for the utilization of glucose as a carbon source using the gene cassette construction according to claim 1.

8. A method comprising:

transforming any host yeast strain for the utilization of any monosaccharide as a carbon source, using the gene cassette construction according to claim 1.

9. The gene cassette construction according to claim 1, wherein the genes are separated by a non-transcribable sequence which is not less than 50 and not more than 200 base pairs.