Oils from Microorganisms

All microorganisms, bacteria, yeasts, fungi, and algae produce a wide variety of lipids. Some species, the oleaginous ones, produce large amounts, sometimes up to 70% of the cell mass, of triacylglycerol oils, which, depending on the organism, are similar in fatty acyl constituents to most of the conventional plant seed oils. These are known as single-cell oils (SCO). They may, if the economics are right, be considered as alternative sources to these commodities. However, because of the high cost of fermentation technology to cultivate microorganisms on a large scale, only the very highest valued microbial oils can be considered economically viable. This chapter gives a brief background to microbial technology and gives examples of how SCOs have been produced as sources of gamma-linolenic acid, being alternatives to evening primrose and borage oils, and for the production of cocoa butter equivalent oils for possible use in chocolate confectionery. Current commercial productions of arachidonic acid (20:4,n-4) using the filamentous fungus, Mortierella alpina, and of docosahexaenoic acid (22:6,n-3) by the marine dinoflagellate, Crypthecodinium cohnii, and by the chytrid, Schizochytrium spp. are described in which oils are produced that are then incorporated into infant baby formulas and are taken for the prevention of coronary heart disease in adults. The prospect of using microorganisms to produce other polyunsaturated fatty acids, such as eicosapentaenoic acid, for possible medical applications, concludes this chapter. Keywords: arachidonic acid; cocoa butter equivalent oils; docosahexaenoic acid; eicosapentaenoic acid; fungi; gamma-linolenic acid; oleaginicity; polyunsaturated fatty acids; single-cell oils; yeasts