EFFECTS OF AGING MORTIERELLA MYCELIUM ON PRODUCTION OF ARACHIDONIC AND EICOSAPENTAENOIC ACIDS

Arachidonic acid and eicosapentaenoic acid (EPA) are important intermediates of eicosanoid metabolism and are presently the subject of extensive nutritional and medical research. The effects of mycelial aging on production of these fatty acids were investigated as part of a research program directed toward examining the feasibility of economically producing these products by fungal fermentation. Arachidonic acid content of M. alpina ATCC 32222 in-creased from 4.1-8.3% to 13-16% during aging while lipid content of mycelium increased from 14-18% to 33-45%. Maximum lipid content produced in biomass during storage declined as harvesting time was increased from 3 to 6 days while maximum arachidonic acid content in lipid increased. Maximum lipid and arachidonic acid was produced during aging at pH 8, whereas arachidonic acid content of lipids was highest in mycelium aged at pH 6. EPA content of M. elongata NRRL 5513 biomass increased during aging, reaching a maximum after 22-28 days. When the pH of the culture prior to harvesting was adjusted in the range of pH 4-9, pH values for development of maximum EPA in biomass and in lipids during storage were found to be 6 and 7, respectively. Temperature of aging had little effect on arachidonic acid or EPA content.