Methods and materials for the production of organic products in cells of candida species
AssigneeNatureWorks LLC
InventorsVineet Rajgarhia, Merja Penttila, Laura Ruohonen, Marja Ilmen, Kari Koivuranta, Pirkko Suominen
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Abstract
The present invention relates to biocatalysts that are cells, optimally of the Crabtree-negative phenotype, comprising expression vectors encoding genes heterologous to the cell that enable increased production of organic products. More specifically, the invention relates to genetically modified Candida cells, methods for making the Candida cells, and their use in production of organic products, particularly lactic acid.
Claims44
A recombinant nucleic acid construct comprising a nucleic acid having a nucleotide sequence encoding a lactate dehydrogenase protein, wherein the lactate dehydrogenase protein is operatively linked to a promoter functional in a yeast cell from a species of genera Candida.
9 The recombinant nucleic acid construct of claim 8, wherein the gene encodes an alpha-galactosidase.
The recombinant nucleic acid construct of claim 9, wherein the gene is yeast MEL5.
A genetically modified cell from genera Candida, comprising at least one exogenous LDH gene.
A Candida cell comprising a deletion at a pdc1 gene locus, a disruption at a pdc2 gene locus and two or more copies of lactate dehydrogenase genes in the cellular genome at each of the pdc1 and pdc2 loci.
20 The cell of claim 19, wherein the two or more copies of lactate dehydrogenase genes are each operably linked to a promoter that is transcriptionally active in the Candida cell.
A Candida cell genetically modified to contain non-functional or deleted pdc1 orpdc2 gene, characterized by at least a 10-fold reduction of ethanol production when cultured in the presence of a defined glucose or rich glucose medium.
32 The method of claim 25, wherein the final pH of the culture medium after lactic acid production is from about pH 2.6 to about pH 5.
A method of reducing pyruvate decarboxylase activity in a cell from genera Candida comprising transforming the cell with the a recombinant nucleic acid construct, wherein the nucleic acid construct comprises a selectable gene flanked by 5′ and 3′ flanking sequences from at least one pyruvate decarboxylase gene native to the genera Candida.
Dependencies are inferred from the claim text.