title: Correlations between FAS elongation cycle genes expression and fatty acid production for improvement of long-chain fatty acids in Escherichia coli.
abstract: Microorganisms have been used for biodiesel (fatty acid methyl ester) production due to their significant environmental and economic benefits. The aim of the present research was to develop new strains of Escherichia coli K-12 MG1655 and to increase the content of long-chain fatty acids by overexpressing essential enzymes that are involved in the fatty acid synthase elongation cycle. In addition, the relationship of β-ketoacyl-acyl carrier protein (ACP) synthase (fabH), β-ketoacyl-ACP reductase (fabG), β-hydroxyacyl-ACP dehydrase (fabZ), and β-enoyl-ACP reductase (fabI) with respect to fatty acid production was investigated. The four enzymes play a unique role in fatty acid biosynthesis and elongation processes. We report the generation of recombinant E. coli strains that produced long-chain fatty acids to amounts twofold over wild type. To verify the results, NAD(+)/NADH ratios and glucose analyses were performed. We also confirmed that FabZ plays an important role in producing unsaturated fatty acids (UFAs) as E. coli SGJS25 (overexpressing the fabZ gene) produced the highest percentage of UFAs (35 % of total long-chain fatty acids), over wild type and other recombinants. Indeed, cis-9-hexadecenoic acid, a major UFA in E. coli SGJS25, was produced at levels 20-fold higher than in wild type after 20 h in culture. The biochemically engineered E. coli presented in this study is expected to be more economical for producing long-chain fatty acids in quality biodiesel production processes.
authors: Department of Chemical and Biomolecular Engineering, Sogang University, Seoul 121-742, Republic of Korea.
authors: Sunhee
authors: S
authors: Lee
authors: Yeontae
authors: Y
authors: Jung
authors: Seunghan
authors: S
authors: Lee
authors: Jinwon
authors: J
authors: Lee
mesh_terms: D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D000123:Acetyltransferases / Q000235:genetics / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D056804:Biofuels; D050753:Enoyl-(Acyl-Carrier-Protein) Reductase (NADH) / Q000235:genetics / Q000378:metabolism; D048168:Escherichia coli K12 / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D054889:Fatty Acid Synthase, Type II / Q000235:genetics / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D060847:Metabolic Engineering; D030781:Organisms, Genetically Modified; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D019745:cis-trans-Isomerases / Q000235:genetics / Q000378:metabolism
chemical_list: D056804:Biofuels; D029968:Escherichia coli Proteins; D005231:Fatty Acids, Unsaturated; D011994:Recombinant Proteins; D000429:Alcohol Oxidoreductases; C023744:acetoacetyl-CoA reductase; D050753:Enoyl-(Acyl-Carrier-Protein) Reductase (NADH); C493924:fabI protein, E coli; D000123:Acetyltransferases; C557158:fabH protein, E coli; D015099:3-Oxoacyl-(Acyl-Carrier-Protein) Synthase; D019745:cis-trans-Isomerases; D054889:Fatty Acid Synthase, Type II