Eicosapentaenoic acid (EPA) production by an oleaginous fungus Mortierella alpina expressing heterologous the Δ17-desaturase gene under ordinary temperature

The oleaginous fungus Mortierella alpina is known to accumulate eicosapentaenoic acid (EPA) only when cultivated at a low temperature (below 15 degrees C). Here, we investigated EPA production at an ordinary temperature (28 degrees C) by expressing the Saprolegnia diclina Delta 17 desaturase gene (sdd17m) in M. alpina ST1358, an omega 3-desaturation activity-defective mutant derived from M. alpina 1S-4. Expression of the exogenous gene was confirmed by EPA accumulation in transformants at both 28 and 12 degrees C. The EPA content in total lipids produced by transformants was over 20% at 28 degrees C. Bench-scale fermentation with a 5-L jar fermentor showed that EPA content reached 26.4% of total fatty acids, and EPA production reached 1.8 g/L. This is the first study to report the accumulation of EPA in M. alpina at an ordinary temperature, and provide a platform technology for the industrial production of EPA using M. alpina as a promising source for EPA.