Probiotic characteristics of phenyllactic acid-producing LAB from swine's digestive tract

Abstract:

[Objective] A simple and efficient method for screening lactic acid bacteria which would produce phenyllactic acid (PLA) would be developed. [Methods] Strain R53 was incubated in MRS ( de Man , Rogosa , Sharpe ) broth supplemented with phenylalanine by the anaerobic culture, and PLA in the fermentation broth was determined by HPLC. [Results] 31 strains were obtained from swine's digestive tract, of which strain R53 from duodenum showed the highest PLA-producing ability (321.7 mg/L). Strain R53 showed the ability to inhibit the on the three radicals. The results showed that the radical-scavenging ratios on ·OH, O2ˉ ,and DPPH were 11.2%, 52.7% and 63.2% respectively. In addition, strain R53 could degrade cholesterol and the degradation rate was 32.5% in vitro. [Conclusion] Strain R53 was identified as Lactobacillus plantarum through its culture characteristics, morphological observation, biochemistry experiment and combining with the phylogenetic analysis of 16S rDNA. L.?plantarum R53 had the ability of phenyllactic acid-producing, cholesterol-reducing, and free radical-scavenging.