Methods for the synthesis of lactic acid using crabtree-negative yeast transformed with the lactate dehydrogenase gene

• US 7,700,332 B1
• Filed: 04/20/2007
• Issued: 04/20/2010
• Est. Priority Date: 05/21/1999
• Status: Expired due to Fees

• Current Assignee: Cargill, Inc. (Agricultural Services Division)
• Original Assignee: Cargill, Inc. (Agricultural Services Division)
• Inventors: Rajgarhia, Vineet, Olson, Stacey, Kolstad, Jeffrey J., Starr, John N., Carlson, Ting, Hatzimanikatis, Vassily, Eyal, Aharon
• Primary Examiner(s): Desai; Anand U
• Application Number:
  US11/788,839
• Time in Patent Office: 1,096 Days
• Field of Search: None
• US Class Current: 435/139
• CPC Class Codes: C12N 1/16 Yeasts; Culture media therefor
• CPC Class Codes: C12P 7/40 containing a carboxyl group including Peroxycarboxylic acids
• CPC Class Codes: C12P 7/48 Tricarboxylic acids, e.g. citric acid
• CPC Class Codes: C12P 7/56 Lactic acid
• CPC Class Codes: C12P 7/60 2-Ketogulonic acid
• CPC Class Codes: Y02E 50/10 Biofuels, e.g. bio-diesel

Abstract

The invention provides methods and materials related to the production of lactic acid. Specifically, the invention provides methods for producing lactic acid using a crabtree-negative yeast, such as of the Kluyveromyces, Pichia, Candida, Trichosporon and Yamadazmya genera, which have been transformed with a lactate dehydrogenase gene.

Claims

1. A method for making lactic acid, said method comprising:

a) providing a microorganism exhibiting a crabtree-negative phenotype and transformed with at least one exogenous gene encoding lactate dehydrogenase;

b) culturing the crabtree-negative microorganism in a first culture medium which includes a carbon source under a first set of culture conditions which promote cellular respiration; and

c) culturing the crabtree-negative microorganism in a second culture medium which includes a carbon source under a second set of culture conditions which promote production of lactic acid.

2. A method for making lactic acid, comprising

a) providing a microorganism exhibiting a crabtree-negative phenotype selected from the group consisting of Kluyveromyces, Pichia, Candida and Hansenula and transformed with at least one exogenous gene encoding lactate dehydrogenase;

b) culturing said crabtree-negative microorganism in a first culture medium which includes a carbon source comprising glucose and under a first set of culture conditions, including a dissolved oxygen content of at least 20 percent relative to the amount present at saturated conditions with air at atmospheric pressure, which promote cellular respiration; and

c) then culturing the crabtree-negative microorganism in a culture medium which includes a carbon source comprising glucose under a second set of culture conditions, including a dissolved oxygen content of less than 2.0 percent relative to the amount present at saturated conditions with air at atmospheric pressure, which promote the production of lactic acid.

3. A method for making lactic acid, comprising

a) providing a microorganism exhibiting a crabtree-negative phenotype selected from the group consisting of Kluyveromyces, Pichia, Candida and Hansenula and transformed with at least one exogenous gene encoding lactate dehydrogenase;

b) culturing said crabtree-negative microorganism in a first culture medium which includes a carbon source comprising glucose and under a first set of culture conditions which promote cellular respiration; and

c) then culturing the crabtree-negative microorganism in a culture medium which includes a carbon source comprising glucose under a second set of culture conditions, including an acidic pH of greater than 1.5, which promote the production of lactic acid.

4. A method for making lactic acid, comprising

a) providing a microorganism exhibiting a crabtree-negative phenotype selected from the group consisting of Kluyveromyces, Pichia, Candida and Hansenula and transformed with at least one exogenous gene encoding lactate dehydrogenase and having a reduced pyruvate decarboxylase activity;

b) culturing said crabtree-negative microorganism in a first culture medium which includes a carbon source comprising glucose and under a first set of culture conditions which promote cellular respiration; and

c) then culturing the crabtree-negative microorganism in a culture medium which includes a carbon source comprising glucose under a second set of culture conditions which promote the production of lactic acid.