Characterization of an Omega-3 Desaturase From and Application for Eicosapentaenoic Acid Production in .

Omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) have important therapeutic and nutritional benefits in humans. In the biosynthesis pathways of these LC-PUFAs， omega-3 desaturase plays a critical role. In this study， we report a new omega-3 desaturase (PPD17) from . This desaturase shares high similarities with the known omega-3 desaturases and was expressed in for the activity and substrate specificity research. The desaturase has a wide omega-6 fatty acid substrate， containing both 18C and 20C fatty acids， and exhibits a strong activity of delta-17 desaturase but a weak activity of delta-15 desaturase. The new desaturase converted the omega-6 arachidonic acid (AA， C20:4) to EPA (an omega-3 LC-PUFA， C20:5) with a substrate conversion rate of 70%. To obtain a high EPA-producing strain， we transformed PPD17 into ， an AA-producing filamentous fungus. The EPA content of the total fatty acids in reconstruction strains reached 31.5% and was followed by the fermentation optimization of the EPA yield of up to 1.9 g/L. This research characterized a new omega-3 desaturase and provides a possibility of industrially producing EPA using .