title: Extending carbon chain length of 1-butanol pathway for 1-hexanol synthesis from glucose by engineered Escherichia coli.
abstract: An Escherichia coli strain was engineered to synthesize 1-hexanol from glucose by extending the coenzyme A (CoA)-dependent 1-butanol synthesis reaction sequence catalyzed by exogenous enzymes. The C4-acyl-CoA intermediates were first synthesized via acetyl-CoA acetyltransferase (AtoB), 3-hydroxybutyryl-CoA dehydrogenase (Hbd), crotonase (Crt), and trans-enoyl-CoA reductase (Ter) from various organisms. The butyryl-CoA synthesized was further extended to hexanoyl-CoA via β-ketothiolase (BktB), Hbd, Crt, and Ter. Finally, hexanoyl-CoA was reduced to yield 1-hexanol by aldehyde/alcohol dehydrogenase (AdhE2). Enzyme activities for the C6 intermediates were confirmed by assays using HPLC and GC. 1-Hexanol was secreted to the fermentation medium under anaerobic conditions. Furthermore, co-expressing formate dehydrogenase (Fdh) from Candida boidinii increased the 1-hexanol titer. This demonstration of 1-hexanol production by extending the 1-butanol pathway provides the possibility to produce other medium chain length alcohols using the same strategy.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, California 90095, USA.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Dekishima
authors.forename: Ethan I
authors.initials: EI
authors.lastname: Lan
authors.forename: Claire R
authors.initials: CR
authors.lastname: Shen
authors.forename: Kwang Myung
authors.initials: KM
authors.lastname: Cho
authors.forename: James C
authors.initials: JC
authors.lastname: Liao
mesh_terms: D020001:1-Butanol / Q000737:chemistry / Q000378:metabolism*; D055162:Biocatalysis; D004798:Enzymes / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D005818:Genetic Engineering; D005947:Glucose / Q000737:chemistry / Q000378:metabolism*; D000441:Hexanols / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004798:Enzymes; D000441:Hexanols; C036260:1-hexanol; D020001:1-Butanol; D005947:Glucose