乳杆菌生物制备共轭亚油酸的研究-环境科学与得工程专业毕业论文.docx

乳杆菌生物制备共轭亚油酸的研究Study 乳杆菌生物制备共轭亚油酸的研究 Study on the Production of Conjugated Linoleic Acid by Lactobacillus sp． Abstract Conjugated linoleic acid(CLA)iS a mixture of positional and geometric isomers of linoleic acid(LA)．Cis-9，trans-1l conjugated linoleic acid(c9，tl 1-CLA)and trans-1 0，cis-1 2 conjugated linoleic acid(t10．C12-CLA)have been confirmed that they are biologically beneficial functional fatty acids， including enhancing organism immunity， immunomodulatory function，preventing atherosclerosis，antioxidant and SO on．CLA has been widely applied in the field of medicine production and food additive． In this research，a strain with high productive ability of CLA was screened．And lOW temperature plasma technology was used in order to improve the production of CLA by the strain．Finally，medium components and fermentation conditions were optimized to increase the production ofCLA．The specific research contents and results are as following： 1．Four strains producing CLA were screened from northeast sauerkraut，fresh milk， yogurt，and activated sludge．Strain SC-05，screened from northeast sauerkraut．has the highest CLA producion．Especially，only c9，t l 1-CLA Was found in the fermentation product using SC一05 strain detected by Gas Chromatography method． 2．Sequencing and analysis of 1 6s rDNA sequence of SC．05 strain．showed that it iS the closest relative With Lactobacillus．SC一05 strain was identified as a strain of Lactobacillus sp． 3．Lactobacillus sp．SC-05 was induced by low temperature plasma，then a mutation strain A-08 Was screened out，by which CLA production could reach 1l 9．24 pg／mL．raised 83．00％compared with in the original strain． 4．The medium components for the strain A-08 to produce CLA were optimized by using orthogonal experiment，and fermentation conditions were studied by using the single factor experiment and response surface method(RSM)．The optimum medium consisted of glucose 3％，peptone 0．5％，beef extract 2％，yeast extract 2％，diammonium citrate 0．2％．sodium acetate 0