Improving Stability and Activity of Cross-linked Enzyme Aggregates Based on Polyethylenimine in Hydrolysis of Fish Oil for Enrichment of Polyunsaturated Fatty Acids
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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.
KeywordsLipase Immobilization Aggregate Cross-linking Polyunsaturated fatty acids
This work was funded by the National High Technology Research and Development Programs of China (No. 2009AA03Z232 and 2010AA101501). The authors acknowledged Engineer Hong Chen (Analytical and Testing Center of Huazhong University of Science and Technology) for her valuable assistance in testing the samples by GC-MS.