Study On The Immobilization Of Lipase From Thermomyces Lanuginosus Onto SBA-15 And Their Catalytic Properties

Diacylglycerols(DAGs)were the natural components in fats and oils,and they have similar appearance,flavor and nutritional value to the ordinary triacylglycerols oil.In addition,DAGs have been claimed to be capable of reducing visceral fat accumulation and preventing body weight increase.DAG can be manufactured either enzymatically or chemically.Among the reaction routes,enzymatic glycerolysis is one of the most promising methods for DAG production.Thermomyces lanuginosus lipase/Humicola lanuginosa lipase(TLL/HLL)is a microbial lipase with good thermostability.Free TLL was however not attractive in practical,especially in large-scale production,due to its easy activity loss and it can not recover for repeated use.The poor operational stability of free lipase could be improved by immobilization,and carrier for immobilization is of critical importance.Of the studied supports,SBA-15 was the most promising candidates for lipase immobilization,due to its large surface area,narrow pore size distribution,thermal and mechanical stability,and sufficient surface silanol groups for surface modification.In this study,TLL was immobilized onto the parent and organic groups modified SBA-15,the enzymatic properties of the obtained immobilized TLL samples were carefully studied.In addition,production of DAG through glycerolysis by the present immobilized TLL was also investigated.Main contents including1)Immobilization of TLL onto the parent SBA-15:enzymatic properties and application for DAG production study.Results indicated that,the obtained SBA-15-TLL exhibited better hydrolytic and glycerolysis activities than that of the commercial Lipozyme TL IM,but operational stability was poorer.The optimal conditions for TLL immobilization were:immobilizationphosphate buffer pH5.0,protein concentration 66.71?g/mL,temperature 40? and time 15 min.With these conditions,activity of the immobilized SBA-15-TLL up to 2862.78 U/g was observed.The SBA-15-TLL was then used to catalyze glycerolysis reaction,and DAG content up to 58.60 wt%was obtained after 3h reaction at 60? in solvent-free system2)Immobilization of TLL onto the organic groups modified SBA-15:enzymatic properties and production of DAG through glycerolysis of soybean oil study.Results indicated that,after organic modification,the obtained R-SBA-15 supported TLL(R-SBA-15-TLL)exhibited higher hydrolytic activity,better thermal stability and reusability.Hydrolytic activities more than 10000 U/g were observed from(?)(?)Particularly,activity up to 14283.33U/g was obtained from(?)The hydrolytic activities of(?)and(?)maintained about 80%of their initial activity after 4 h incubation at 70? in n-hexane system.(?)maintained 60%of their initial activity after five cycles reuse.In addition,organic functionalization of SB A-15 had decreased the sensitivity of the immobilized TLL in a wide pH range.Reaction conditions were optimized and DAG content up to 59.19 wt%was obtained after 2 h reaction at 60?with(?)as catalyst.Moreover,the(?)showed good reusability in glycerolysis,with 95.21%of its initial glycerololysis activity retained after five cycles reuse.In the meantime,the organic functionalized SBA-15 and the thereafter supported TLL samples were characterized by XRD,XPS,FT-IR,TEM and SEM,and results confirmed the successful organic modification and TLL immobilization.In addition,the ordered mesostructure of the SBA-15 was retained after the organic modification and there after TLL immobilization.In this study,hydrolytic and glycerololysis activities of SBA-15-TLL and R-SBA-15-TLL were explored.(?)was found to be a promisingimmobilized lipase with higher hydrolytic and glycerololysis activities,and better reusability in glycerolysis reaction.The present study provided theoretical basis and technical support for TLL immobilization and its application in DAG production.