Abstract

Ten strains were isolated from Algerian fruits were tolerance to acid pH and bile salts and were furthermore identified as Lactiplantibacillus plantarum (L. plantarum) strains by MALDI-TOF mass spectrometry and 16S rDNA sequencing. The identified strains were then characterised for their surface properties such as self-aggregation, hydrophobicity and biofilm formation. The resulting data were then statistically processed using Principal Component Analysis (PCA), after which only 5 strains were selected for further analysis. These five strains, named L. plantarum 1, 2, 3, 4 and 5, were found to be safe and able to adhere to human epithelial colorectal adenocarcinoma Caco-2 cells. In particular, all these strains were active against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538 through the production of lactic acid (up to 12g.L^-1) or bacteriocins, namely plantaricin, or their combination. In addition, these strains showed high antioxidant activity against the synthetic free radical 2,2-diphenyl-2-picrylhydrazyl (DPPH) and the 2,2-azino-bis: 3-ethyl-benzothiazoline-6-sulphonic acid (ABTS+) radical going up to 78.93 ± 1.18% and 50.06 ± 6.47% respectively. Taken together, these results delineate the different beneficial functions of these L. plantarum strains from plant sources and consider them potentially usable as probiotics, biotechnological and biopreservative agents