Stereospecific production of 9R-hydroxy-10E,12Z-octadecadienoic acid from linoleic acid by recombinant Escherichia coli cells expressing 9R-lipoxygenase from Nostoc sp. SAG 25.82

One of the most significant properties of lipoxygenase (LOX) as a biocatalyst is its stereo-selective oxygenation. In this study, the stereo-specific production of 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from linoleic acid was achieved using whole recombinant Escherichia coli cells expressing LOX from Nostoc sp. SAG 25.82. The optimal conditions for the production of 9R-HODE were pH 7.5, 25 °C, 40 g l^-1 cells, 15 g l^-1 linoleic acid, 2% (v/v) methanol, 1 working volume/oxygen volume/min (vvm) oxygenation rate, and 250 rpm agitation speed in 500 ml-baffled flask containing a working volume of 50 ml. Under these optimized conditions, whole recombinant cells expressing 9R-LOX protein produced 14.3 g l^-1 9R-HODE for 1 h, with a conversion yield of 95% (w/w) and a productivity of 14.3 g l^-1 h^-1. The oxygen supply method significantly influenced stereo- and regio-selectivity of the oxygenation of linoleic acid. Among the oxygen supply methods tested, oxygenation (1 vvm) with agitation (250 rpm) resulted in the highest 9R/13S-HODE ratio of the products at 96:4. This is the first application using whole recombinant cells harboring R-specific LOX for the stereo-selective production of an R-specific hydroxy fatty acid.