Study On Feed Additive Conjugated Linoleic Acid Biosynthesis

Conjugated Linoleic Acid (CLA) is a kind of fatty acid with functions such as anti-tumor, anti oxidation, body weight lossing, improving immunity et al. Meat from ruminant milk and dairy products are natural resources of CLA. It can also be transformed from linoleic acid (LA) by chemical methods, with products of mixed isomers and by-products might damage to environment. The purpose of this work is to establish a biosynthesis method to produce CLA using LA as substance. There are three parts in this study.Conjugated linoleic acid analysis methods. Spectrophotometer method was caried out since CLA has an absorption value under light long of 233 nm while LA does not have. Gas Chromatography (GC-MS) was used to separate fatty acids with different carbon length and numbers of double bonds in unsaturated fatty acid.Engneering bacteria and it’s fermentation conditions. A gene of linoleic acid isomerase (PAI), originated from acne propionic acid bacillus, with the function of catalyzing LA to cis-12, trans-10 CLA, was synthesied by Shanghai Jie Rui company. The gene was transformed, the PAI was expressed with the function of biosynthesis of CLA from LA in E. coli. The optimum fermentation conditions of the engneering bacteria were using concentration 1‰ LA, at temperature 40℃, and with pH value 6.7.Fermentation with lipase and cells immobilization. Two from 8 candidate lipases was selected to using safflower seed oil as the substrate. With the technology of cells immobilization, the output reached more than 39%.