DOCOSAPENTAENOIC ACID (C22 5, OMEGA-3) PRODUCTION BY PYTHIUM-ACANTHICUM/

The physiological roles of omega-3 fatty acids, eicosapentaenoic acid and docosahexaenoic acid have been investigated in detail and microbia l strains producing these polyunsaturated fatty acids have been charac terised, It has recently been suggested that docosapentaenoic acid may have an important role, especially in infant nutrition, and that its positive health effects have been overlooked. Docosapentaenoic acid (C 22:5, omega-3) production by a strain of Pythium acanthicum ATCC 18660 was thus investigated, Optimum conditions for growth of P, acanthicum ATCC 18660 and docosapentaenoic acid production were: pH 6.0, tempera ture 20 degrees C and incubation time, 10 days. Among different saccha rides and complex nitrogen sources tested, glucose and sodium glutamat e were preferred carbon and nitrogen sources, respectively. Maximum bi omass content (10.4 g L-l) and docosapentaenoic acid yield (49.9 mg L- 1) were obtained in 10 days, An increase in docosapentaenoic acid volu metric yields to 108-110 mg L-1 was obtained when linseed oil was used to supplement glucose or soy fllour-containing medium. Batch feeding of additional glucose or linseed oil further enhanced the docosapentae noic acid volumetric yield to 132 mg L-1 and 125 mg L-1, respectively, in 14 days, The specific production of docosapentaenoic acid in preli minary experiments ranged from 1.0-5.0 mg g(-1) biomass, As conditions were optimised, docosapentaenoic acid specific production titers were generally in the range of 4.0-5.5 mg g(-1) and increases in docosapen taenoic acid volumetric production could be attributed to increased bi omass production. The limited improvement obtained by modifying cultur e conditions indicates that increasing volumetric yields of docosapent aenoic acid by modifying culture conditions appears to represent a sig nificant barrier to commercialisation of such a process and suggests a more fundamental manipulation of metabolism and physiology is require d.