Study On The Processing Of Conjugated Linoleic Acid From Sea-buckthorn Using Biotransformation Linoleic Acid Isomerase By Lactobacillis Spp.

The Sea buckthorn resource is rich in our country,accounting for 95%of the world sea-buckthorn total sown area.It contains abundant bioactive substances,rich in nutrition.The large berry cultivars sea-buckthorn seeds oil is rich in unsaturated fatty acid,among which,the contents of linoleic acid and linolenic acid are more than 80%.Conjugated linoleic acid(CLA) refers to a mixture of positional and geometric isomers of linoleic acid with conjugated double bonds.It has been proven to have extensive physiological function and it has become the focus of studies.This article mainly discussed screening production of a linoleic acid isomerase by fermentation with a Lactobacillus spp. was studied.The enzyme was purified and immobilized enzyme characteristic was determined.The main results of this paper are as follows:(1) Screening the best enzyme activity from several Lactobacillus spp.Emulsifyied of sea-buckthorn seed oil was added into the compound of Lactobacillis spp.as substrate,LA isomerase produced by Lactobacillis spp.was used to convert linoleic acid(LA) into conjugated linoleic acid(CLA).The experiment proved that the selected the highest conjugated conversion ratio of strain into MRS liquid medium for cultivation of Lactobacillus plantarum, Lactobacillus plantarum produced by fermentation of linoleic acid isomerase activity for:13.82U, It's conversion rate of conjugate 17.68%.This study established the theoretical foundation for producing conjugated linoleic acid from Large Berry Cultivars Sea-Buckthorn seed oil by biological method.(2) Optimization of Fermentation Conditions of a LA isomerase for Lactobacillus plantarumOn the basis of single factor experiments,the optimum conditions for the extraction of polysaccharide were obtained through Box-Benhnken center-united experiment design and response surface methodology with 4 factors and 3 levels.Then the factors influencing the technological parameters were determined by meaxls of regression analysis.Response surface and contour were finally graphed with the CLA conversion ratio as the response value.The optimum conditions of a LA isomerase for Lactobacillus plantarum production were as follows:Incubation time of 30.21h,Incubation temperature of 36.22℃,Inoculation amount(v/v) is 1.99%and Concentration of sea-buckthom seeds oil(v/v) is 9.62%.The CLA conversion ratio is 20.46%under the optimum conditions.(3) Optimization of conditions of Immobilized of LA isomerase and Study on the propertiesThe research included selection of immobilized carrier,determination of the immobilized conditions.The experiments results showed that immobilized LA isomerase entrapped by embedding medium of calcium alginate gel kept the better catalysis.The optimal conditions by response surface for embedding were:enzyme added 1.2mL,sodium alginate concentration 2.84%, Immobilized time 6.42h,CaCl₂ concentration 3.77%.In the condition,the actuality CLA conversion ratio of immobilized enzyme was 15.76%.The results showed that the optimal temperature and pH were 35 and 6.5,and also the significant elevation of immobilized enzyme in the thermal stability, pH stability and storage stability.Km and Vmax dynamics parameters of LA isomerase,were respectively 21.756μmol/L,1.065μmol/h·mg。...