Geotrichum candidum NRRL Y-553 lipase: purification, characterization and fatty acid specificity

Lipases from Geotrichum candidum NRRL Y-553 are of interest because of their unique specificity for cis-9-unsaturated fatty acids relative to both stearic and palmitic acids. The lipases were partially purified by chromatography on Octyl Sepharose, AG MP-1 macroporous anion exchanger, and chromatofocusing resin. The preparation was found to contain multiple, glycosylated lipases varying slightly in pI (pI 4.88, 4.78, 4.65, 4.57 and 4.52) as judged by both activity and silver staining. The molecular mass determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis was 64 kilodaltons for the main species, with minor species of 60 and 57 kilodaltons present as well. The specificity of the crude lipases for hydrolysis of 4-methylumbelliferyl esters of oleic vs. palmitic acid was 20-to-1. The specificity of the purified, partially separated lipases was similar to that of the crude preparation. Thus the lipases could be used even in crude form for the hydrolysis and restructuring of triacylglycerols on a large scale.