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Food Lipids: Chemistry, Nutrition, and Biotechnology

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Figure 13 Microbial production of lactones.<br />

esterification, <strong>and</strong> transesterification of lipids has been exploited in commercial processes<br />

for the modification of fats <strong>and</strong> other lipids.<br />

The substrate specificities <strong>and</strong> regioselectivities in the hydrolysis of triacylglycerols,<br />

catalyzed by some common <strong>and</strong> commercially available lipases, are summarized<br />

in Table 8 (99–103). It is evident that the triacylglycerol lipases have widely<br />

varying substrate specificities preferring substrates with long <strong>and</strong> medium chain fatty<br />

acids over the short chain ones <strong>and</strong> vice versa. Moreover, specificity of lipases for<br />

the fatty acids esterified at the sn-1, sn-2, <strong>and</strong> sn-3 positions of the glycerol backbone<br />

vary widely, ranging from nonspecificity for either of the three sn-1, sn-2, <strong>and</strong> sn-3<br />

positions to strong sn-1,3 or sn-3 specificity.<br />

In general, the substrate specificity <strong>and</strong> positional specificity of triacylglycerol<br />

lipases observed in the hydrolysis reactions are also maintained in the reverse re-<br />

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

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