| Conjugated linoleic acid (CLA) was a octadecadienoic acid (C 18:2) containing conjugated double bonds. CLA had a term of positional and geometric isomers.Two of the isomers, cis-9 trans-11 and trans-10 cis-12, could confer a number of beneficial biological effect. The two isomers,that were attened at home and abroad, show to anti-neoplasm, anti-atherosclerosis, reduce fat, immuno modulatio, diabetes mellitus ect.. Method of bioconversion can produce pure CLA from LA with single isomer at light-duty test. The mechanism was that the existence of linoleate isomerase enzyme convert linoleic acid to CLA. So the study of linoleate isomerase enzyme had been the focus of considerable research efforts in recent years.The research Lactobacillus delbrueckii subsp bulgaricus to extract Linoleic acid isomerase.Basic on detected the product of Linoleic acid isomerase, production condition for Linoleic acid isomerase with Lactobacillus delbrueckii subsp bulgaricus were investigated. Then studied purification of Lionleic ismerase in Lactobacillus delbrueckii subsp bulgaricus, andSome of the enzymatic propertie. Preliminary research on response system.Through a combination of tow detection methods of GC-MS, Ag+-HPLC, determined the main product of CLA which had tow isomer, and mainly contained c9,tll-CLA.The production condition for Linoleic acid isomerase with Lactobacillus delbrueckii subsp bulgaricus were investigated. The result showed that the highest yield was obtained when 1.5%o of LA (v/v) was added to the medium. The Optimum condition for Lactobacillus delbrueckii subsp bulgaricus culture was shown as follows:temperature was 36℃and time was 36 h. Individually adding 0.1% (m/v)of Lactose, or 0.1%(m/v) of NaCl was added to medium, respectively, Linoleic acid isomerase which was favor to producing CLA was obtained in good yield. The results of LA added directly to medium was favor to that of LA added to medium when bacillus had cultrued 3 h to 12 h.The optimum condition of extract was that frist mix gently with 0.7%(m/v) lysozyme powder and incubating for 1h at 30℃,the cells were disrupted by sonication for 10min at power 400w working 3s and resting 4s in 0℃.The optimum saturation of Ammonium sulphate for linoleate isomerase was 40-80%. Used an Amicon centrifugal filter unit fitted with a Centriplus-15 membrane of 30 kDa nominal weight cut off for protein. Sephadex G-100 gel fractionation chromatography, achieving an overall purification of 5.17-fold and a spectic activity of 244.78[U/mg]. The purified enzyme was a single distinct protein band by SDS-PAGE, with an estimated molecular weight of about 42.69KDa.Some of the enzymatic properties were the optimum temperature of Lionleic ismerase was 40℃, the ismerase exhibited high stability under the water bath of 20℃～40℃. The optimum pH of Lionleic ismerase was 4.0. Within pH values range from 3.0 to 6.0, the ismerase exhibited high stability. Same metal ions such as Ca2+,Zn2+, Mg2+at low concentration (0.01mol/L) pofit Lionleic ismerase. Effct was Ca2+>Zn2+>Mg2+. SDS at high concentration (0.02mol/L) pofit Lionleic ismerase.Using LA as substrate, the Km of Lionleic ismerase was 3.87mmol/L, the Vmax was 4.35mmol/L·h.Research on response system of Lionleic ismerase in Lactobacillus delbrueckii subsp bulgaricus. Lionleic ismerase in Lactobacillus delbrueckii subsp bulgaricus in potassium phosphate buffer system was optimized. Hexane was suit to use as organic medium.At micro-water medium adding 0.6% potassium phosphate buffer pofit Lionleic ismerase.The benefit condition in two-phase medium on the conversion of CLA by linoleate isomerase two-phase volume ratio of Hexane and buffer was 6:4. Ethanol was harmful to linoleate isomerase and didn't fit for using in homogeneous-phase medium.
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