Substratselektivität von Lipasen bei der Veresterung und Umesterung cis-trans-isomerer Fettsäuren und Fettsäureester

• Main Author: Borgdorf, Robert
• Other Authors: Warwel, Siegfried
• Format: Doctoral or Postdoctoral Thesis
• Language: German
• Published: Publikationsserver der RWTH Aachen University 2005
• Subjects: info:eu-repo/classification/ddc/570; Biowissenschaften; Biologie; Lipase; Substratselektivität; Veresterung; Fettsäuren; cis/trans-Isomere; substrate selectivity; esterification; fatty acids; cis/trans-isomers; Antarc*; Antarctica
• Online Access: https://publications.rwth-aachen.de/record/62184; https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123773%22

The aim of this doctoral thesis was the systematic determination of substrate selectivity of lipases towards unsaturated fatty acids and fatty acid esters with respect to position and configuration of C=C-double bonds. First, the substrate selectivity of 39 lipases from microorganisms, plants and animal tissue has been examined in the esterification of cis- and trans-9-octadecenoic acid (oleic and elaidic acid respectively) with n-butanol in n-hexane. While most of the lipases were unspecific towards the isomeric 9-octadecenoic acids, lipases from Candida cylindracea and Mucor miehei had a strong preference for the cis-9-isomer and catalysed the esterification of oleic acid 3-4 times faster than the reaction of elaidic acid. Only Candida antarctica lipase A favoured the trans-9-isomer as substrate and esterified elaidic acid 15 times faster than oleic acid. Examining the substrate selectivity in the esterification of linoleic (all-cis-9,12-octadecadienoic) acid, linolenic (all-cis-9,12,15-octadecatrienoic) acid and their all-trans-isomers with n-butanol in n-hexane as well as in the transesterification of cis/trans-isomeric 9,12-octadecadienoic acid methyl esters with n-butanol in n-hexane, once again lipases from Candida antarctica and Mucor miehei preferred fatty acids and fatty acid esters with a (first) cis double bond in delta-9-position, while the lipase A from Candida antarctica accepted trans-9-unsaturated substrates with high selectivity. Furthermore, lipases from Candida cylindracea and Mucor miehei as well as the lipase A from Candida antarctica has been used as biocatalysts in the esterification of the commercially available conjugated linoleic acid (CLA) isomers cis-9,trans-11-, cis-9,cis-11-, trans-9,trans-11- and trans-10,cis-12-octadecadienoic acid with n-butanol in n-hexane. As expexted, the cis-9-selective lipases from Candida cylindracea and Mucor miehei had a preference for the cis-9,trans-11-octadecadienoic acid, while the Candida antarctica lipase A favoured the trans-9, trans-11-isomer as ...