Expansion of the ω-oxidation system AlkBGTL of Pseudomonas putida GPo1 with AlkJ and AlkH results in exclusive mono-esterified dicarboxylic acid production in E. coli.
The AlkBGTL proteins coded on the alk operon from Pseudomonas putida GPo1 can selectively ω-oxidize ethyl esters of C6 to C10 fatty acids in whole-cell conversions with Escherichia coli. The major product in these conversions is the ω-alcohol. However, AlkB also has the capacity to overoxidize the substrate to the ω-aldehyde and ω-acid. In this study, we show that alcohol dehydrogenase AlkJ and aldehyde dehydrogenase AlkH are able to oxidize ω-alcohols and ω-aldehydes of esterified fatty acids respectively. Resting E. coli expressing AlkBGTHJL enabled exclusive mono-ethyl azelate production from ethyl nonanoate, with an initial specific activity of 61 U gcdw-1. Within 2 h, this strain produced 3.53 mM mono-ethyl azelate, with a yield of 0.68 mol mol-1. This strain also produced mono-ethyl dicarboxylic acids from ethyl esters of C6 to C10 fatty acids and mono-methyl azelate from methyl nonanoate. Adding ethyl nonanoate dissolved in carrier solvent bis-(2-ethylhexyl) phthalate enabled an increase in product titres to 15.55 mM in two-liquid phase conversions. These findings indicate that E. coli expressing AlkBGTHJL is an effective producer of mono-esterified dicarboxylic acids from fatty acid esters.
Bioprocess Engineering, Wageningen University and Research, Wageningen, the Netherlands.
Youri M
YM
van Nuland
Bioprocess Engineering, Wageningen University and Research, Wageningen, the Netherlands.
Fons A
FA
de Vogel
Bioprocess Engineering, Wageningen University and Research, Wageningen, the Netherlands.|Biobased Products, Wageningen University and Research, Wageningen, the Netherlands.
Gerrit
G
Eggink
Bioprocess Engineering, Wageningen University and Research, Wageningen, the Netherlands.
Ruud A
RA
Weusthuis
D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D003998:Dicarboxylic Acids / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D004952:Esters / Q000378:metabolism*; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D010084:Oxidation-Reduction; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism*
D003998:Dicarboxylic Acids; D004952:Esters; D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase