Conjugated Linoleic Acid Mutagenic Breeding Of High Yield Strain And Optimization Of Culture Medium And Fermentation Conditions

Conjugated linoleic acid or CLA, it as an indispensable part of human body health, fattyacids and attention.CLA has anti-cancer function not only, still have as prevention and treatmentof atherosclerosis, prevention and treatment of diabetes, immune regulation, improve bonedensity and participate in fat catabolism. Therefore CLA by food additives industry、pharmaceutical industry、health care products industry wide attention. But of CLA production bychemical method is difficult to meet the requirements of the food industry high purity, so usingthe method of microbial synthesis of CLA were attaches great importance to food industry, bythe microbial method can obtain high purity, pollution-free products, is advantageous to thedevelopment and application of the product. This paper with seven kinds of lactic acid bacteria,lactobacillus, lactobacillus acidophilus, lactobacillus case, lactobacillus, lactic acid milk coccus,thermophilic streptococcus, as the research object, lactobacillus fermentation strains screeningfor high yield of conjugated linoleic acid, mutagenesis, the best culture medium and cultureconditions comprehensive study, USES the single factor experiment, the response surfaceoptimization analysis method, to determine the strain of process conditions, and carries on theoptimization and verification, the results are as follows:By fermentation test, and with uv-vis spectrophotometer detection, found in the experiment offive of seven kinds of lactic acid bacteria strains of bacteria fermented liquid extract maximumabsorption peak at233nm. Their ability to produce CLA. The heart type of lactobacillusfermented CLA content in the highest, the yield of0.055mg/mL.Good for type for incipient lactobacillus strains, using ultraviolet mutagenesis and diethylsulfate method, achieving high yield strain of conjugated linoleic acid mutant strain. Ultravioletmutagenesis irradiation time for35seconds, strain fatality rate is76%. Diethyl sulfateconcentration was2%, the processing time is35minutes, strain fatality rate was74%.Experiment found that Germany’s mixed lactobacillus Bulgaria subspecies by UV and DESmutagenesis, has made great improve its ability to produce CLA, content is0.210mg/mL. D-2-2high yield strain got from mutagenesis was identified the species and determined it was theGermany’s lactobacillus Bulgaria subspecies.Will get a mutant strain of10generations to extendtest，test found that the mutant strain of CLA production change is not big, can draw mutant strain D-2-2has better characteristics of genetic stability, so the mutant strains has been shownto steady heredity.By means of conjugated linoleic acid best medium carbon source, nitrogen source, inorganicsalt determination of optimal proportion. Choose glucose as the sole carbon source, within thescope of experiment the effects of inorganic salts in medium of potassium hydrogen phosphate>sodium acetate and magnesium sulfate. Sodium acetate content is5.525g/L, potassium hydrogenphosphate content is2.81g/L, magnesium sulfate content is0.325g/L, CLA yield the optimalvalue of0.241245mg/mL. Within the scope of the nitrogen source in the experiment on theinfluence of the culture medium of yeast powder> peptone> citric acid diamine> beef paste.Peptone content is12.5g/L, yeast powder content is6.57g/L, citric acid diamine content is1.61g/L, beef extract content is7.5g/L, CLA yield the optimal value of0.267mg/mL.By means of conjugated linoleic acid optimal cultivation temperature and time, thedetermination of growth pH, culture conditions of conjugated linoleic acid in experimental scopegrowth followed by the influence of pH> time> temperature. Temperature is36℃, pH7,42hof incubation time, CLA yield the optimal value of0.292mg/mL.