title: Improving stability and activity of cross-linked enzyme aggregates based on polyethylenimine in hydrolysis of fish oil for enrichment of polyunsaturated fatty acids.
abstract: Cross-linking of enzyme aggregates from recombinant Geotrichum sp. lipase based on polyethylenimine (PEI) was applied to hydrolyze fish oil for enrichment of polyunsaturated fatty acids successfully. Through acetone precipitation and cross-linking of physical aggregates using glutaraldehyde in the presence of PEI, firmly cross-linked enzyme aggregates (PEI-CLEAs) were prepared. They could maintain more than 65% of relative hydrolysis degree after incubation in the range of 50-55 °C for 4 h and maintain more than 85% of relative hydrolysis degree after being treated by acetone, tert-butyl alcohol and octane for 4 h. PEI-CLEAs increased hydrolysis degree to 42% from 12% by free lipase. After five batch reactions, PEI-CLEAs still maintained 72% of relative hydrolysis degree. Hydrolysis of fish oil by PEI-CLEAs produced glycerides containing concentrated EPA and DHA in good yield. PEI-CLEAs had advantages over general CLEAs and free lipase in initial reaction rate, hydrolysis degree, thermostability, organic solvent tolerance and reusability.
authors.affiliation: Key Laboratory of Molecular Biophysics, Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan, China. yjiny@126.com
authors.forename: Jinyong
authors.initials: J
authors.lastname: Yan
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Gui
authors.forename: Guilong
authors.initials: G
authors.lastname: Wang
authors.forename: Yunjun
authors.initials: Y
authors.lastname: Yan
mesh_terms: D003432:Cross-Linking Reagents / Q000737:chemistry; D004281:Docosahexaenoic Acids / Q000302:isolation & purification*; D015118:Eicosapentaenoic Acid / Q000302:isolation & purification*; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D017743:Equipment Reuse; D005395:Fish Oils / Q000737:chemistry*; D005656:Fungal Proteins / Q000737:chemistry*; D005848:Geotrichum / Q000737:chemistry* / Q000201:enzymology; D005976:Glutaral / Q000737:chemistry; D006868:Hydrolysis; D007700:Kinetics; D008049:Lipase / Q000737:chemistry*; D009795:Octanes; D011094:Polyethyleneimine / Q000737:chemistry; D012997:Solvents; D020002:tert-Butyl Alcohol / Q000737:chemistry
chemical_list: D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D005395:Fish Oils; D005656:Fungal Proteins; D009795:Octanes; D012997:Solvents; D004281:Docosahexaenoic Acids; D011094:Polyethyleneimine; D015118:Eicosapentaenoic Acid; D008049:Lipase; D020002:tert-Butyl Alcohol; D005976:Glutaral; C026728:octane