Selective Production of 9R-Hydroxy-10E,12Z,15Z-Octadecatrienoic Acid from α-Linolenic Acid in Perilla Seed Oil Hydrolyzate by a Lipoxygenase from Nostoc Sp. SAG 25.82.

Abstract

Hydroxy fatty acids (HFAs) derived from omega-3 polyunsaturated fatty acids have been known as versatile bioactive molecules. However, its practical production from omega-3 or omega-3 rich oil has not been well established. In the present study, the stereo-selective enzymatic production of 9R-hydroxy-10E,12Z,15Z-octadecatrienoic acid (9R-HOTE) from α-linolenic acid (ALA) in perilla seed oil (PO) hydrolyzate was achieved using purified recombinant 9R-lipoxygenase (9R-LOX) from Nostoc sp. SAG 25.82. The specific activity of the enzyme followed the order linoleic acid (LA) > ALA > γ-linolenic acid (GLA). A total of 75% fatty acids (ALA and LA) were used as a substrate for 9R-LOX from commercial PO by hydrolysis of Candida rugosa lipase. The optimal reaction conditions for the production of 9R-HOTE from ALA using 9R-LOX were pH 8.5, 15°C, 5% (v/v) acetone, 0.2% (w/v) Tween 80, 40 g/L ALA, and 1 g/L enzyme. Under these conditions, 9R-LOX produced 37.6 g/L 9R-HOTE from 40 g/L ALA for 1 h, with a conversion yield of 94% and a productivity of 37.6 g/L/h; and the enzyme produced 34 g/L 9R-HOTE from 40 g/L ALA in PO hydrolyzate for 1 h, with a conversion yields of 85% and a productivity of 34 g/L/h. The enzyme also converted 9R-hydroxy-10E,12Z-octadecadienoic acid (9R-HODE) from 40 g/L LA for 1.0 h, with a conversion yield of 95% and a productivity of 38.4 g/L. This is the highest productivity of HFA from both ALA and ALA-rich vegetable oil using LOX ever reported. Therefore, our result suggests an efficient method for the production of 9R-HFAs from LA and ALA in vegetable oil using recombinant LOX in biotechnology.