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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Table 5 Levels of Major Constituent Polyunsaturated Fatty Acids in<br />

Biomass of Lipid-Accumulating Molds<br />

Organism<br />

Major polyunsaturated fatty acid<br />

Fatty acid a<br />

(% w/w of total<br />

fatty acids) Ref.<br />

Mortierella isabellina 18:3�6 8 2<br />

Mucor javanicus 18:3�6 15–18 2<br />

Mucor ambiguus 18:3�6 11–14 16<br />

Mortierella rammaniana 18:3�6 26 17<br />

Mortierella alpina 20:3�6 23 18<br />

20:4�6 11<br />

Mortierella alpina 20:4�6 69–79 19<br />

Mortierella elongata 20:4�6 15 20<br />

Mortierella alpina 20:4�6 31 21<br />

Mortierella alpina 20:4�6 43–66 22<br />

Mortierella alpina 20:4�6 32–57 23<br />

Mortierella alpina 20:5�3 15 24<br />

Pythium irregulare 20:5�3 25 25<br />

Pythium irregulare 20:5�3 24 26<br />

Thraustochytrium aureum 20:6�3 40–50 27<br />

Thraustochytrium aureum 20:6�3 29 28<br />

Thraustochytrium aureum 20:6�3 40 29<br />

a Fatty acids are designated by number of C atoms (left of colon) <strong>and</strong> number of cis<br />

double bonds (right of colon).<br />

A few species of marine bacteria have also been found to produce substantial<br />

proportions of polyunsaturated fatty acids, such as eicosapentaenoic acid (35,36) <strong>and</strong><br />

docosahexaenoic acid (37) in the lipids of their biomass.<br />

3. Wax Esters<br />

Several reports are known on the production of wax esters by Acinetobacter sp. H01-<br />

N grown on a wide variety of n-alkanes of chain lengths ranging from C16 to C20 (38,39). In general, the chain lengths of the waxes formed depend on the chain length<br />

of the alkane (38), e.g.,<br />

C n-alkane → C2 � C2 � C2 wax esters<br />

n n n�2 n�4<br />

In addition to saturated wax esters, those containing up to two double bonds are also<br />

formed from n-alkanes <strong>and</strong> carbon sources, such as ethanol, acetic acid, propanol,<br />

<strong>and</strong> propionic acid (39). Typical composition of wax esters produced by Acinetobacter<br />

sp. H01-N from various carbon sources is summarized in Table 6.<br />

The microalgae Euglena gracilis (ATCC 12716), grown on yeast malt extract,<br />

synthesize wax esters having saturated even carbon numbered acids <strong>and</strong> alcohols<br />

ranging from C 12–C 18 as the major constituents (40).<br />

Copyright 2002 by Marcel Dekker, Inc. All Rights Reserved.

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