Comparative Study On The Preparation Of OPO By Two Lipase Catalyzed Transesterification Of Oleic Acid And Palm Stearin And Reuse Of Lipase

1,3-Dioleoyl-2-palmitoylglycerol(OPO)is a nutritional supplement for infant formula.GB 30604-2015 points out that OPO should be prepared through lipase-catalyzed transesterification.Due to different activity and cost of lipases,it is necessary to optimize the reaction conditions for the industrial purpose.To save the cost of OPO production,two strategies in terms of developing cheap lipase and reuse of lipase have been taking into consideration.In this presented study,OPO was prepared through Novozym 40086 and VL089 catalyzed transesterification,the reaction conditions were optimized.The reuse performance of Novozym 40086 and VL089 was also evaluated under the optimal reaction conditions.Firstly,OPO was prepared by transesterification of oleic acid and palm stearin catalyzed by Novozym 40086.In single-factor test,lipase dosage was chosen based on cost and number of cycles.Response surface methodology was employed to optimize the reaction conditions.The optimal conditions were as follows:substrate ratio,5.7:1(oleic acid:palm stearin,mol/mol);Novozym 40086 dosage,6.3%(based on the substrates mass,w/w);reaction time,6.8 h;temperature,60 ~oC.Under the optimal conditions,the content of OPO,PPP and palmitic acid at sn-2 position of all palmitic acid were 43.13%,7.65%and61.28%,respectively,which match the requirement of GB 30604-2015.Secondly,OPO was prepared transesterification of oleic acid and palm stearin catalyzed by lipase VL089,which is low cost than Novozym 40086.The optimal conditions were as follows:VL089 dosage,9.4%(based on the substrate mass w/w);substrate ratio,8:1(oleic acid:palm stearin,mol/mol),reaction time,6.8 h;temperature,60~oC.Under optimal conditions,the content of OPO,PPP and palmitic acid at sn-2 position of all palmitic acid were 44.23%,7.73%and 63.01%,respectively,which match the requirement of GB 30604-2015.Compared with Novozym 40086 catalyzed reaction,more oleic acid and larger lipase dosage were needed in the VL089 catalyzed system.However,due to the low cost of VL089,the total cost of OPO production was lower.Therefore,VL089 can be used as the biocatalyst for industrial OPO production.Lastly,since the high price of lipase and the high cost of OPO production,it is necessary to increase the cycle numbers of lipase to decrease production cost.Taking the content of OPO,PPP and palmitic acid at sn-2 position of all palmitic acid as the evaluation criterion,under the optimal conditions,the cycle number of Novozym 40086 and VL089were once and twice,respectively.The corresponding products match the requirement of GB 30604-2015.Under the same conditions,Novozym 40086 perform better than VL089.The reuse of Novozym 40086 and VL089 was evaluated by adding original lipase(20%,each time)under the optimal conditions.It was found that amount of OPO produced by one kilogram of Novozym 40086(22.22 kg)was higher than that of one kilogram of VL089(18.72 kg).The reaction time of Novozym 40086 was shorter than that of VL089.However,the price of VL089 was about 30%of Novozym 40086.Therefore,the actual purpose,the cost of substrates and products should take into consideration when select lipase.