Metal salts requisite for the production of eicosapentaenoic acid by a marine bacterium isolated from mackerel intestines

Metal salts important for the growth and 5,8,11,14,17- ciseicosapentaenoic acid EPA) production of a bacterium isolated from Pacific mackerel intestines were investigated at 25°C in culture media containing 1.0% peptone and 0.50% yeast extract, and the composition of an optimum culture medium was determined. This bacterium could grow in the media in which sodium chloride was the sole added inorganic component. By raising the concentration of sodium chloride from 1.2 to 2.4%, the yield of bacterial cells increased and the yield of EPA reached a maximum at 2.0% NaCl concentration. In contrast to calcium chloride, potassium chloride and magnesium chloride as second metal salts promoted the growth of this bacterium at relatively low concentrations without inhibiting the accumulation of EPA. The yield of EPA reached its maximum value of 51.9 mg/L of culture broth at 8 hr at 2.0% NaCl, 0.15% KCl and 0.16% MgCl₂ concentrations. This yield of EPA was 20% greater than that obtained with Jamarin S artificial sea water. *To whom correspondence should be addressed at Department of Chemical Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152, Japan. ¹Sagami Chemical Research Center, 4-4-1 Nishi-ohnuma, Sagamihara, Kanagawa 229, Japan.