Methods and compositions for the production of fatty acids in photosynthetic prokaryotic microorganisms

摘要

Provided herein are methods and compositions for the production of renewable fatty acids from photosynthetic prokaryotic microorganisms, such as a blue green algae, any specie of the phylum Cyanophyta, a chloroplast of a green algae and/or a Cyanobacterium. Engineered or natural strains of these organisms or organelles can be used to produce both saturated and unsaturated fatty acids with variable chain length specificity from 8-18 carbons. The fatty acids can then be secreted into the culture medium, allowing for rapid, continuous and efficient separation of fatty acid product without harvesting of cell mass.

主权项

1. A method for producing a monounsaturated fatty acid in a photosynthetic Cyanobacterium comprising:
(i) providing a photosynthetic Cyanobacterium, wherein the photosynthetic Cyanobacterium is:
(a) genetically engineered to have a disrupted chromosomal ribulose-1,5-bisphosphate carboxylase/oxygenase (RUBISCO) gene;(b) transformed with a nucleic acid comprising a promoter sequence operably linked to a heterologous nucleic acid sequence encoding a stearoyl-acyl carrier protein (ACP)-desaturase polypeptide which produces or catalyzes the synthesis of a monounsaturated fatty acid-ACP in the photosynthetic Cyanobacterium, and(c) transformed with a nucleic acid comprising a promoter sequence operably linked to a heterologous nucleic acid sequence encoding an oleoyl- and/or a palmitoleoyl-acyl carrier protein (ACP) thioesterase, wherein the thioesterase hydrolyses ACP from a growing acyl chain to terminate elongation of the acyl chain to form a fatty acid, wherein co-expression of the oleoyl- and/or palmitoleoyl-ACP thioesterase with the stearoyl-ACP-desaturase in the photosynthetic Cyanobacterium produces or catalyzes the synthesis of a monounsaturated fatty acid in the photosynthetic Cyanobacterium; and (ii) culturing the photosynthetic Cyanobacterium in a culture medium such that the oleoyl- and/or palmitoleoyl-ACP thioesterase is or are co-expressed with the stearoyl-ACP-desaturase, thereby producing the monounsaturated fatty acid.