In the present study, a total of 554 lactic acid bacteria (LAB) isolates were obtained from the olive surface of Manzanilla, Gordal, and Aloreña cultivars processed as green Spanish-style or directly brined (natural) olives. The isolates obtained from industrial processes were genotyped by rep-PCR with primer GTG 5 , collecting a total of 79 different genotypes. The α-biodiversity indexes showed that the LAB diversity was higher in the biofilms on the fruits which followed the Spanish-style process than in those just brined. Sixteen genotypes had a frequency higher >1% and were identified, by multiplex PCR recA gene and 16S gene sequencing, as belonging to Lactobacillus pentosus ( n = 13) and Lactobacillus plantarum ( n = 3) species. A multivariate analysis based on a dataset with 89,744 cells, including technological (resistance to salt and pH, production of lactic acid, auto and co-aggregation with yeast species, β-glucosidase and esterase activities), and potential probiotic characteristics (survival to gastric and pancreatic digestions, resistance to antibiotics, inhibition of pathogens, presence of bsh genes, cholesterol removal, hemolytic, α-glucosidase, β-galactosidase, and phytase activities) showed that the 16 genotypes could be grouped into 3 great phenotypes. Thus, the genotype biodiversity in table olive biofilms was limited but, at phenotype level, it was even lower since L. pentosus predominated clearly (80.15% isolates). L. pentosus Lp13 was the genotype with the most promising characteristics for its use as a multifunctional starter, with this strain being and ubiquitous microorganism present in both natural and lye-treated olive fermentations.

This work examines the formation of poly-microbial communities adhered to the epidermis of natural green Gordal olives and the application of different methodologies for recovery and counting of the microorganisms embedded in olive biofilms. The fermentation process was physicochemical and microbiologically monitored for 90 days, at which, formation of true biofilms on the skin of fermented fruits was confirmed by scanning electron microscopy. Then, samples of olives were taken and treated with sonication, enzymes, mechanical homogenization with stomacher and ultrasonic bath for biofilm disaggregation. The use of the stomacher for 1 min was the most effective treatment to release the lactic acid bacteria (6.6 log10 cfu g(-1)), whereas sonication for 5 min was the most efficient method for quantification of yeasts (up to 3.5 log10 cfu g(-1)). Molecular identification of isolates obtained from natural Gordal olive biofilms revealed that Lactobacillus pentosus was the only species found among lactic acid bacteria, while Pichia membranifaciens was the dominant yeast species, with higher counts obtained for the bacteria.