Application Of Lipase In The Fish Oil Transesterification

This study,with a commercialized lipase which provided by an enzyme company as catalyst in the fish oil transesterification,concentrated high content of EPA and DHA in triglyceride.The enzymology propertied of the Aspergillus Niger lipase were researched by measuring enzymatic activity,and were comparative with Novozyme435 studying that the levels of factors affected the content of EPA and DHA in triglyceride by catalyzing transesterification of glyceryl and ester.The content of EPA and DHA in triglyceride was separated by thin layer chromatography and determined by gas chromatograph.The optimum was figured out by a four factors and three levels of Response Surface Methodology.The constitute and physicochemical property of glyceride and the composition fatty acid of triglyceride analyzed by high efficiency liquid chromatography,gas chromatograph,thin layer chromatography and national standards.The results of the study showed,the thermal stability of the Aspergillus Niger lipase was 20?40?;the optimum temperature was 40?50?;The pH stability was 5.0?7.0;the optimum pH value was 6.0?7.0;The effect of organic solvents on the enzyme activity was not obvious;It's only Ca2+ Puts a positive role on the enzyme activity among those activator.The results of the single factor showed,the Aspergillus Niger lipase and Novozyme435 had the same property in concentrating the EPA and DHA in triglyceride in the fish oil transesterification.The effect of interaction found by Response Surface Methodology;The most obvious effect factor of lipase to catalyze transesterification was reaction temperature,and then reaction time,enzyme dosage and substrate quality ratio.The content of EPA and DHA in triglyceride was enriched by the catalysis of the Aspergillus Niger lipase from 30.02%to 52.85%,the content of EPA is enriched from 19.21%to 33.67%,the content of DHA is enriched from 10.81%to 19.18%.Compared with Novozyme435 catalyzed by enriching EPA and DHA which was about 48.57%in many study.The results showed that the catalytic ability of the Aspergillus Niger lipase is better,which was significantly higher than Novzyme435 about 4.28%of the content of EPA and DHA.The results of the reaction product physical,chemical properties,fatty acid composition and content which the Aspergillus Niger lipase catalyzed in the fish oil transesterification in the optimum condition showed,the AV value,POV value,saponification value and iodine value were 0.12 mg/g?2.34 mmol/kg?152 mg/g and 216 g/100g,which met the national requirements of a standard level of fish oil.Before and after the ester exchange reaction,the total content of 14:0,16:0,16:1 and 18:1 of the triglyceride were from 44.16%to 26.46%,the total content of EPA and DHA were from 30.02%to 52.85%,so mainly EPA and DHA replaced the 14:0,16:0,16:1 and 18:1 of the triglyceride.