The present invention relates to a fungal C1618 fatty acid elongase that is able to catalyze the conversion of palmitate to stearic acid. The method includes the steps of: providing an electrical apparatus and an AC power; generating a control signal synchronized to the AC power; and controlling the electrical apparatus by the control signal. The reaction produces a mixture containing a 1:1 ratio of 9Z, 11E, 15Z-octadecatrienoic acid and 9Z, 13E, 15Z-octadecatrieonic acid.