Enzymatic Production Of The Fish Oil Rich In Polyunsaturated Fatty Acids By Aspergillus Oryzae Lipase

Both Cis-5,8,11,14,17-eicosapentaenoic(EPA)and cis-4,7,10,13,16,19-docosahexaenoic(DHA)are n-3 polyunsaturated fatty acids(PUFA),which have been shown to have various beneficial effects on human health.The best edible form of EPA and DHA is glycerol ester.Due to the relative low content of EPA and DHA in natural fish oil,the preparation of glycerol ester rich in n-3PUFA has become more attractive recently in the research area.Whereas nowadays the preparation mostly were used with commercial lipases,which has limited the industrial application due to the high price of commercial enzyme.In this research,Aspergillus oryzae WZ007 was isolated and it's lyophilized mycelium of A.oryzae WZ007 was successfully cdeveloped to catalyze alcoholysis and transesterification to produce fish oil rich in PUFA with the domestic anchovy fish oil as raw material.First of all,this paper developed an inspection method for EPA and DHA based on gas chromatography.The reaction condition of alcoholysis of fish oil catalyzed by lyophilized mycelium of A.oryzae WZ007 was optimized.Employing a fed-bath operation with alcohol(the total substrate molar ratio is 1:2.1)under the reaction temperature of 60 ?and rotation speed of 250 rpm after 13h,coupled with 11%(w/v)of lyophilized mycelium,conversion could be obtained 43.64%,with an increase of EPA in triglycerides from original 11.5%to 16.42%,and DHA from 14.5%to 22.73%.Optimized conditions of transesterification between ethyl esters of fish oil and triglycerides of fish oil were as follows:the substrate molar ratio was 1:3(TAG:EE),lyophilized mycelium was 14%,reaction temperature was 70 ? and the rotation speed was 150 rpm.Under the optimized condition,the contents of EPA and DHA could reach 39.72%after 18 h,and 41.78%after 48 h of reaction.Meanwhile,the mycelium could be used for six times with the remaining enzyme activity above 35%.