Oils from Microorganisms

Abstract

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.

An efficient multi-stage fermentation strategy for the production of microbial oil rich in arachidonic acid in Mortierella alpina

“…Although feather-like hyphal filaments (Fig. 2a) were observed to be optimal for ARA production at low densities (Park et al 1999), this morphology is disadvantageous at high cell densities because viscosity of the ferrmentation broth may be increased to an extent that oxygen transmission becomes limited (Wynn and Ratledge 2005).

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Alternative Sources of n-3 Long-Chain Polyunsaturated Fatty Acids in Marine Microalgae

“…Microalgae species considered oleaginous contain at least 20% lipid of their biomass, and levels can range up to 70% with TAGs accounting for over 90% of the total lipid [53,61]. However, TAGs are usually high in saturated and monounsaturated fatty acids (MUFA) [62], hence, partitioning of LC-PUFA into TAGs is seldom found.…”

“…Nannochloropsis Hibberd, Phaeodactylum Bohlin, Nitzschia Hassall and Porphyridium Nägeli can present elevated levels of EPA in total fatty acids, although relatively low cell lipid contents tend to result in small EPA amounts in the biomass (Table 2). Photoautotrophic species contain lipids involved in the photosynthetic metabolism and, unlike various DHA-rich microalgae, the fatty acid profiles of EPA producers usually show other LC-PUFA, like DHA and/or AA [61]. …”

Improving microbial oil production with standard and native oleaginous yeasts by using Taguchi design

“…A key enzyme in citric acid cycle is isocitrate dehydrogenase that becomes inactive in the absence of nitrogen. This leads to isocitrate not being metabolized, and consequently, isocitrate and citric acid accumulate in mitochondria and immediately transport to the cytoplasm of the oleaginous yeasts (Melickova et al 2004;Wynn and Ratledge 2005).…”