Abstract:[Objective] This study aimed to screen functional lactic acid bacterial strains with high L-histidine production from fermented foods and evaluate their probiotic characteristics. [Method] The probiotic characteristics of the isolates were assessed by determining their growth curves, acid-producing profiles, optimal growth temperature and pH, stress resistance characterization, antibiotic susceptibility, and inhibitory activity against pathogens.[Result]Limosilactobacillus fermentum NC42 with a L-histidine yield of 939.77 mg/L was successfully screened out. This strain had a lag growth phase from 0 h to 6 h, a logarithmic growth phase from 6 h to 18 h, and a stable growth phase after 18 h. The optimal growth temperature and pH were 37 ℃ and 6.0, respectively. The results of the stress resistance characterization showed that this strain could not survive when the NaCl mass fraction was above 4%, and it could tolerate strong acidic environments with pH 2.5 and 3.0 and maintain a good viable count at a bile salt mass fraction of 0.10%. This strain could maintain a viable count sufficient for probiotic effects for 5 d at -20 ℃. The results of surface property determination showed that its hydrophobicity was determined to be 43.27%, which indicated moderate hydrophobicity. The self-agglomeration rate of this strain was 52.13%. The strain showed significant differences in sensitivity to different antibiotics, with sensitivity to penicillin, erythromycin, and cefazolin. The fermentation supernatant of this strain had significant inhibitory effects on various indicator pathogens, with the most obvious inhibitory effect on Listeria monocytogenes, as evidenced by the inhibition zone diameter of 17.10 mm. [Conclusion] The screened strain had certain probiotic characteristics and stress resistance, which provides a basis for the functional probiotic development.
