title: Efficient display of active Geotrichum sp. lipase on Pichia pastoris cell wall and its application as a whole-cell biocatalyst to enrich EPA and DHA in fish oil.
abstract: Geotrichum  sp. lipase (GSL) was first displayed on the cell wall of  Pichia pastoris  on the basis of the a-agglutinin anchor system developed in  Saccharomyces cerevisiae . Surface display levels were monitored using Western blotting, immunofluorescence miscroscopy, and fluorescence-activated cell sorting analysis. Lipase activity of the yeast whole cells reached a maximum at 273 ± 2.4 U/g of dry cells toward olive oil after 96 h of culture at 30 °C, with optimal pH and temperature at 7.5 and 45 °C, respectively. Displayed GSL exhibited relatively high stability between pH 6.0 and 8.0 and retained >70% of the maximum activity. The surface-displayed lipase retained 80% of its original activity after incubation at 45 °C for 4 h. Moreover, the GSL-displaying yeast whole cells were then used as a biocatalyst to enrich eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil on the basis of selective hydrolysis. As a result, EPA and DHA increased from 1.53 and 24.1% in the original fish oil to 1.85 and 30.86%, which were increases of 1.21- and 1.29-fold, respectively. The total yield of EPA and DHA reached 46.62%.
authors.affiliation: Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology,  Huazhong University of Science and Technology , Wuhan 430074, People's Republic of China.
authors.forename: Xiao-Xing
authors.initials: XX
authors.lastname: Pan
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiao
authors.initials: X
authors.lastname: Xiao
authors.forename: Xiao-Feng
authors.initials: XF
authors.lastname: Wang
authors.forename: Yun
authors.initials: Y
authors.lastname: Liu
authors.forename: Hou-jin
authors.initials: HJ
authors.lastname: Zhang
authors.forename: Yun-Jun
authors.initials: YJ
authors.lastname: Yan
mesh_terms: D001483:Base Sequence; D002384:Catalysis; D002473:Cell Wall / Q000201:enzymology* / Q000378:metabolism; D004281:Docosahexaenoic Acids / Q000378:metabolism*; D015118:Eicosapentaenoic Acid / Q000378:metabolism*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000378:metabolism; D005395:Fish Oils / Q000737:chemistry / Q000378:metabolism*; D005434:Flow Cytometry; D005527:Food, Fortified; D005848:Geotrichum / Q000201:enzymology; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D037102:Lectins / Q000737:chemistry; D008049:Lipase / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010843:Pichia / Q000201:enzymology*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics; D013696:Temperature
chemical_list: D004800:Enzymes, Immobilized; D005395:Fish Oils; D037102:Lectins; D011994:Recombinant Proteins; C482094:agglutinin-A; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid; D008049:Lipase