Screening Of Conjugated Linoleic Acid High-Yielding Lactic Acid Bacteria

Conjugated linoleic acid(CLA)is the isomer of linoleic acid(LA),which has a noveltype of biologically beneficial functional including reduces carcinogenesis,reducesbody fat,immunity regulation,and anti-atherosclerosis. Presently,CLA is producedthrough chemical isomerization of linoleic acid(LA),but products contain severalisomers. CLA isomers are much simpler through biological isomerization of LA thanthrough chemical. And the isomers are similar with the nature food. It has a goodbusiness future for CLA which is isomerized by microorganism.CLA production lactobacillus were screened from pickle juice through UVspectrophotometry, and were identified according to Bergey's Manual of SystemaicBacteriology.High-yielding CLA lactobacillus was indued by ultraviolet tradiationand diethyl sulfate(DES) mutant.The process of CLA production by Lactobacillusplantarum were studied. The research include screening, identification inducedmutation, fermentated,culture optimization and optimal condition of fermentation. Thestudy content includes:First, Lactic acid bacteriaX11, with a high ability to produce CLA,was isolatedfrom pickle juice was identified as a strain of Lactobacillus plantarum.Secongd, L. plantarumX11 was indued by ultraviolet tradiation and DES,a mutationstrain L. plantarumX11-3-1 was screened out with the highest production of CLA.Theoptimal fermented culture contents contains (w/v):glucose (3%),peptone (1%),yeastextract(0.5%),beef extract(1%), citric acid diamine (0.1%), sodium acetate(0.5%),potassium dihydrogen phosphate(0.2%),magnesium sulfate(0.02%),Tween80(0.12%).The CLA concentration was 0.342mg/ml in optimal fermented culture pH6.5which was added 0.1% (v/v)linoleic acid and was fermented 36h at 34℃.The yield ofCLA is 37.9%.