Production of 11R-hydroxyeicosatetraenoic acid from arachidonic acid by Escherichia coli cells expressing arachidonate 11R-lipoxygenase from Nostoc sp.

Linoleate 9R-lipoxygenase (9R-LOX) from Nostoc sp. SAG 25.82 was identified as arachidonate (ARA) 11R-LOX by the determination of the product obtained from the conversion of ARA. The specific activity and catalytic efficiency (k_cat/K_m) of the enzyme for C20 and C22 polyunsaturated fatty acids followed the order ARA > eicosapentaenoic acid > docosahexaenoic acid. The production of the lipid mediator 11R-hydroxyeicosatetraenoic acid (11R-HETE) was performed using Escherichia coli cells expressing ARA 11R-LOX from Nostoc sp. The reaction conditions, such as pH, temperature, solvent and its concentration, and substrate and cell concentrations, were optimized using the recombinant cells, and the optimal conditions for the production of 11R-HETE from ARA were pH 7.0, 25°C, 10 g L⁻¹ cells, 5.0 mM ARA, 4% (v/v) ethanol, and 10 mM cysteine as a reducing agent. Under these optimized conditions, E. coli cells expressing 11R-LOX converted 5.0 mM ARA into 4.74 mM 11R-HETE in 60 min, with a molar conversion yield of 95% a volumetric productivity of 79 μM min⁻¹ and a specific productivity of 7.9 μM min⁻¹ g⁻¹. To the best of our knowledge, this is the first report on the quantitative biotechnological production of 11R-HETE.