Determination of Antioxidant and Antimicrobial Activities of Cell-Free Supernatant (CFSKC27L) and Exopolysaccharide (EPSKC27L) obtained from Ligilactobacillus salivarius KC27L

Abstract

Twenty-six lactic acid bacteria were obtained from poultry feces sampled located in the Ankara area (Türkiye) and belong to the Lactobacillus genus according to the results obtained by biochemical methods. This study screened these isolates for exopolysaccharides (EPS) production. EPS production was detected in these isolates, varying from 8 mg L-1 to 353 mg L-1. The highest EPS-producing isolate (KC27L) was selected for further studies. The isolate was identified as Ligilactobacillus salivarius by 16S rRNA analysis. Furthermore, the anti-biofilm and antioxidant abilities of the cell-free supernatant (CFSKC27L) and different concentrations (0.5 mg L-1 and 1 mg L-1) of EPS belonging to the KC27L strain (EPSKC27L) that exhibited high EPS production were determined. CFSKC27 and different concentrations (0.5 mg L-1 and 1 mg mL-1) of EPSKC27L determined the anti-biofilm impact on Escherichia coli ATCC 11229, Enterococcus faecalis ATCC 29212, and Staphylococcus aureus EB-1. The highest anti-biofilm effect in 1 mg mL-1 EPSKC27L was detected at E. coli ATCC 11229 with 87 % inhibition. Three different methods (1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating and superoxide anion radical scavenging activity) designated antioxidant activity. The highest 1.1-Diphenyl-2-picrylhydrazyl radical (DPPH) removal impact, Fe2+ ion chelating, and superoxide anion radical scavenging activity were found in 1 mg mL-1 EPSKC27L (79.6%, 24.9%, and 61.6%, respectively). Both anti-biofilm and antioxidant activities of 1 mg mL-1 EPSKC27L were higher than postbiotic. Finally, its molecular characterization was done following the partial purification of the EPSKC27L. The EPSKC27L has two fractions with molecular weights of 1.6x103 and 6.4 x104 Da. Monosaccharide components of EPSKC27L were found to be glucose (53.1%), fructose (18.5%), arabinose (14.6%) and mannose (13.8%). CFSKC27L and EPSKC27L obtained from L. salivarius can be antioxidants and anti-biofilm agents.