09.12.2012 Views

Food Lipids: Chemistry, Nutrition, and Biotechnology

Food Lipids: Chemistry, Nutrition, and Biotechnology

Food Lipids: Chemistry, Nutrition, and Biotechnology

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Lysophosphatidic acid has been prepared in a yield of 32% by direct solventfree<br />

esterification of fatty acids to sn-glycerol-3-phosphate, catalyzed by triacylglycerol<br />

lipase from Rhizomucor miehei (302). Immobilized sn-1,3-specific triacylglycerol<br />

lipase from Rhizopus arrhizus has been found to efficiently catalyze the<br />

transesterification of DL-glycero-3-phosphate with lauric acid vinyl ester yielding<br />

lysophosphatidic acids (1-acyl-rac-glycero-3-phosphate) <strong>and</strong> phosphatidic acids (1,2diacyl-rac-glycero-3-phosphate)<br />

in a total conversion of >95% (303). The conversions<br />

were lower (55%) with oleic acid as acyl donor in the corresponding esterification<br />

reaction (303).<br />

Transesterification of L-�-glycerophosphocholine with vinyl esters of fatty<br />

acids such as vinyl laurate, catalyzed by C<strong>and</strong>ida antarctica lipase B (Novozym<br />

435) in the presence of tert-butanol, gives predominantly 1-acyllysophosphatidylcholine<br />

with high (>95%) conversion (304). Similarly, esterification of fatty acids<br />

with L-�-glycerophosphocholine, catalyzed by Rhizomucor miehei lipase (Lipozyme<br />

IM) in the presence of dimethylformamide, produces 1-acyllysophosphatidylcholine<br />

with high (90%) conversion (305).<br />

Transesterification reactions, such as acidolysis, i.e., exchange of the constituent<br />

fatty acids of diacylglycerophosphocholines, have been carried out against other fatty<br />

acids added as reaction partners using sn-1,3-specific triacylglycerol lipase from Rhizopus<br />

delemar as biocatalyst (306) (Fig. 38). Similarly, transesterification of diacylglycerophospholipids,<br />

catalyzed by sn-1,3-specific or nonspecific triacylglycerol<br />

lipases, has been applied to modify the fatty acid composition of diacylglycerophospholipids,<br />

specifically at the sn-1 position or at both sn-1 <strong>and</strong> sn-2 positions<br />

(295,296,307–312). In transesterification of phosphatidylcholine with a fatty acid,<br />

catalyzed by triacylglycerol lipases from Rhizopus delemar, Rhizomucor miehei<br />

(308), or Rhizopus arrhizus (309,310) acyl exchange occurs almost exclusively at<br />

the sn-1 position. Polyunsaturated fatty acids, especially �3 PUFA, have been incorporated<br />

into phospholipids by transesterification catalyzed by sn-1,3-specific triacylglycerol<br />

lipases from Rhizopus delemar (311) <strong>and</strong> Rhizomucor miehei (312), as<br />

outlined in Fig. 40.<br />

Transesterification of eicosapentaenoic acid with phosphatidylcholine from soybean,<br />

catalyzed by an sn-1,3-specific triacylglycerol lipase from Rhizomucor miehei<br />

in the presence of a combination of water <strong>and</strong> propylene glycol yields a therapeutically<br />

beneficial phospholipid (301).<br />

Figure 40 Preparation of structured phospholipids by transesterification of diacylglycerophospholipids<br />

with �3 polyunsaturated fatty acids catalyzed by triacylglycerol lipases.<br />

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

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!