Screening and Identification of High-Yielding Strains of Conjugated Linoleic Acid and Optimization of Conditions for the Conversion of CLA

Conjugated linoleic acid (CLA) is a class of naturally occurring octadecadienoic acid in humans and animals and is a general term for a group of conformational and positional isomers of linoleic acid. In order to obtain the development of excellent lactic acid strains with a high production of conjugated linoleic acid, 32 strains with a possible CLA conversion ability were obtained by initial screening using UV spectrophotometry, and then the strains were re-screened by gas chromatography, and finally, the strain with the highest CLA content was obtained. The strains were optimized for cultivation by changing the amount of substrate addition, inoculum amount, and fermentation time. The results showed that the yield of the experimentally optimized strain for the conversion of conjugated linoleic acid could reach 94.68 ± 3.57 μg/mL, which was 74.4% higher than the initial yield of 54.28 ± 2.12 μg/mL of the strain. The results of this study can provide some basis for the application of conjugated linoleic acid production by Lactobacillus paracasei in the fermentation of lactic acid bacteria.