Screening Bacteria Of Producing Conjugated Linoleic Acid And Optimization Of The Fermentation Condition

Conjugated linoleic acid (CLA) is a natual fatty acid which has a wide range ofbeneficial effects, such as anticancer, losing weight, antiatherogenic, and so on. At present, theproduction of CLA is mainly produced by chemical synthesis, but there are many unsafefactors in chemical synthesis production. Thus, people pay more attention to biosynthesis ofCLA. So, it must have a good business future.Two bacteria producing CLA were screened from pickle juice, named G3and G6seperately. They were identified according to physiology and biochemistry. The resultsshowed that: they were classified in Lactobacillus SP. In order to get a high CLA production,the fermental conditions were optimized on Lactobacillus G3,G6and Lactobacillusacidophilus LP preserved in our laboratory. The optimal conditions for Lactobacillus G3transforming LA to CLA were as follows: safflower oil0.15%, initial pH5.5, inoculum size5%, culture temperature37℃, culture time48hours, then the concentration of CLA reached70.16μg/mL. The optimal conditions for Lactobacillus G6transforming LA to CLA were asfollows: safflower oil0.15%, initial pH5.5, culture temperature33℃, culture time48hours,then the concentration of CLA reached81.22μg/mL. The optimal conditions for Lactobacillusacidophilus LP transforming LA to CLA were as follows: safflower oil0.20%, initial pH6.5,inoculum size3%, culture temperature37℃, culture time60hours, then the concentration ofCLA reached95.64μg/mL.UV inducement was put on Lactobacillus acidophilus LP to get a steady becteriumLactobacillus acidophilus LY-7with high CLA production, the total CLA yield was156.28μg/mL. The fermental conditions were opitimized on Lactobacillus acidophilus LY-7by response surface design method. The optimal conditions were that: cuture time36h,temperature40.24℃, safflower oil0.105%, pH6.4, inoculum size6.87%, and total CLAreached311.79μg/mL.