Food Lipids: Chemistry, Nutrition, and Biotechnology

Some other biosurfactants include emulsan, a lipopolysaccharide produced by
an Acinetobacter strain (51), surfactin, produced by Bacillus subtilis, which is a
heptapeptide linked with �-hydroxymyristic acid by an ester and an amide bond (52)
and penta- and disaccharide lipids produced by Nocardia corynebacteroides sp. (53).
Glycolipids containing sophorose and �- or(�-1)-hydroxy C 16/C 18 acids, bound as
glycosides or esters, have been produced by the yeast Candida bombicola grown on
glucose and 2-dodecanol (54).
B. Biotransformation of Fats and Lipids Using Whole
Microbial Cells
Bioconversions of fats using whole microbial cells is a promising approach for largescale
economical production of fat-based products. The following selected examples
show the applications of microbial biotransformations for the preparation of specific
products from fats, fatty acids, and their derivatives.
1. Wax Esters
Cells of the alga Euglena gracilis (55,56) and other algae (57), as well as microorganisms
such as Corynebacterium sp. (58), have been shown to catalyze the esterification
of fatty acids with long chain alcohols yielding wax esters (Fig. 4).
2. Hydroxy Acids and Other Oxygenated Fatty Acids
Numerous examples of microbial oxidation of unsaturated fatty acids for the preparation
of hydroxy fatty acids have become known (see Ref. 59 for review). The
microbial enzymes involved in oxidation of unsaturated fatty acids to hydroxy acids
via hydration (Fig. 5) are termed monooxygenases, which catalyze the incorporation
of one atom of molecular oxygen into a substrate, while the other atom is reduced
to water (60). Dioxygenases catalyze the incorporation of both atoms of molecular
oxygen into the substrate.
Since the initial reports by Wallen et al. (61) on the hydration of the olefinic
bond of oleic acid to 10-hydroxystearic acid by Pseudomonas sp., hydration of oleic
Figure 4 Microbial production of wax esters.
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