title: Fatty acid production in genetically modified cyanobacteria.
abstract: To avoid costly biomass recovery in photosynthetic microbial biofuel production, we genetically modified cyanobacteria to produce and secrete fatty acids. Starting with introducing an acyl-acyl carrier protein thioesterase gene, we made six successive generations of genetic modifications of cyanobacterium Synechocystis sp. PCC6803 wild type (SD100). The fatty acid secretion yield was increased to 197 ± 14 mg/L of culture in one improved strain at a cell density of 1.0 × 10(9) cells/mL by adding codon-optimized thioesterase genes and weakening polar cell wall layers. Although these strains exhibited damaged cell membranes at low cell densities, they grew more rapidly at high cell densities in late exponential and stationary phase and exhibited less cell damage than cells in wild-type cultures. Our results suggest that fatty acid secreting cyanobacteria are a promising technology for renewable biofuel production.
authors.affiliation: Center for Infectious Diseases and Vaccinology, and Center for Environmental Biotechnology, the Biodesign Institute, Arizona State University, Tempe, AZ 85287, USA.
authors.forename: Xinyao
authors.initials: X
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Sheng
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
mesh_terms: D056804:Biofuels; D029968:Escherichia coli Proteins / Q000096:biosynthesis* / Q000235:genetics; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism*; D008245:Lysophospholipase / Q000096:biosynthesis* / Q000235:genetics; D030781:Organisms, Genetically Modified / Q000235:genetics / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000096:biosynthesis* / Q000235:genetics; D046939:Synechocystis / Q000201:enzymology* / Q000235:genetics; D013869:Thiolester Hydrolases / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D056804:Biofuels; D029968:Escherichia coli Proteins; D005227:Fatty Acids; D033903:Periplasmic Proteins; D008245:Lysophospholipase; D013869:Thiolester Hydrolases; C400724:tesA protein, E coli; C018748:oleoyl-(acyl-carrier-protein) hydrolase