Diversity and Antimicrobial Properties of Lactic Acid Bacteria Isolated from Rhizosphere of Olive Trees and Desert Truffles of Tunisia

Abstract

A total of 119 lactic acid bacteria (LAB) were isolated, by culture-dependant method, from rhizosphere samples of olive trees and desert truffles and evaluated for different biotechnological properties. Using the variability of the intergenic spacer 16S-23S and 16S rRNA gene sequences, the isolates were identified as the genera Lactococcus, Pediococcus, Lactobacillus, Weissella, and Enterococcus. All the strains showed proteolytic activity with variable rates 42% were EPS producers, while only 10% showed the ability to grow in 9% NaCl. In addition, a low rate of antibiotic resistance was detected among rhizospheric enterococci. Furthermore, a strong antibacterial activity against plant and/or pathogenic bacteria of Stenotrophomonas maltophilia, Pantoea agglomerans, Pseudomonas savastanoi, the food-borne Staphylococcus aureus, and Listeria monocytogenes was recorded. Antifungal activity evaluation showed that Botrytis cinerea was the most inhibited fungus followed by Penicillium expansum, Verticillium dahliae, and Aspergillus niger. Most of the active strains belonged to the genera Enterococcus and Weissella. This study led to suggest that environmental-derived LAB strains could be selected for technological application to control pathogenic bacteria and to protect food safety from postharvest deleterious microbiota.

Microbial cell-free extracts as sources of enzyme activities to be used for enhancement flavor development of ewe milk cheese

“…Characteristic polypeptide bands appeared in the WC cheese, which showed the most complex profile. The contribution of W. cibaria to proteolysis in cheeses or other fermented foods (e.g., sourdough, table olives) was previously described (Capuani et al, 2013;Fhoula et al, 2013). As previously shown (Coda et al, 2006), primary proteolysis of Italian Pecorino cheeses was characterized by the intense or complete hydrolysis of α S1 -CN, which indicated considerable chymosin activity.…”

Screening for Lactobacillus plantarum with potential inhibitory activity against enteric pathogens

“…In contrast, the antibacterial activity of IMAU80087 cell-free supernatant was not affected by such pH adjustment; and its activity against Escherichia coli O157:H7 was even enhanced after the pH change. Although it has previously been suggested that LAB antibacterial activities against Gram-negative bacteria are related to the organic acid effect or other bioactive materials, which have a potent effect at acidic range (Fhoula et al 2013), results from strains IMAU80076, IMAU70104, and IMAU80087 illustrated that other bacterial inhibitory mechanisms may be involved.…”

Biochemical and Microbiological Analysis of Different Organic Manures: Their Effect on Germination of Coriandrum sativum (Cilantro) and Solanum melongena (Eggplant)

“…Per se, the genera Lactobacillus is not a plant growth promoting rhizobia (PGPR) but few results have shown their presence in rhizosphere [21] and has plant-growth promoting activity [22] presumably due to its active secretions. We believe that it may be due to its antibacterial activities, secretion of vitamins and other co-factors due to which they display beneficial properties in the mammalian gut.…”