Continue to hypothesize that honey is a storehouse of beneficial bacteria, and the majority of these isolates are levansucrase producers. Accordingly, ten bacterial strains were isolated from different honey sources. Four honey isolates that had the highest levansucrase production and levan yield were identified by the partial sequencing of the 16S rRNA gene as Achromobacter sp. (10A), Bacillus paralicheniformis (2M), Bacillus subtilis (9A), and Bacillus paranthracis (13M). The cytotoxicity of the selected isolates showed negative blood hemolysis. Also, they are sensitive to the tested antibiotics (Amoxicillin + Flucloxacillin, Ampicillin, Gentamicin, Benzathine benzylpenicillin, Epicephin, Vancomycin, Amikacin, and Zinol). The isolates had strong alkaline stability (pHs 9, 11) and were resistant to severe acidic conditions (29–100 percent). The tested isolates recorded complete tolerance to both H2O2 and the bile salt (0.3% Oxgall powder) after 24 h incubation. The cell-free supernatant of the examined strains had antifungal activities against C. Albicans with varying degrees. Also, isolates 2M and 13M showed strong activities against S. aureus. The isolates showed strong adhesion and auto-aggregation capacity. Isolate 10A showed the highest antioxidant activity (91.45%) followed by 2M (47.37%). The isolates recorded different catalase and protease activity. All isolates produced cholesterol oxidase and lipase with different levels. Besides, the four isolates reduced LDL (low-density lipoprotein) to different significant values. The cholesterol-reducing ability varied not only for strains but also for the time of incubation. The previous results recommended these isolates be used safely in solving the LDL problem.

Various strategies, like those using vaccines and antibiotics, have been examined for the prevention and treatment of virus's diseases, but until this moment infection control is not at sufficient level. Exopolysaccharides, especially from probiotics, became one of the most innovative approaches for antiviral agents. This research tried to highlight the effect of a probiotic polysaccharide, such as levan, in COVID-19 prevention. Accordingly, 5 levans types previously obtained from bacterial honey isolates were tested against COVID-19. The most promising result was recorded with levans from Pseudomonas aeruginosa HI1 (levAE) and Bacillus subtilis 9A (lev9A). The lowest cytotoxicity was obtained from lev9A (CC 50 =5.567e+006 mg/ml) and the most promising IC 50 was obtained by levAE (10.75 mg/ml) followed by lev13M (142.5 mg/ml) then lev9A (1299 mg/ml). The dialysis process of levAE greatly affected the virus inhibition activity (IC 50 of levAE/D =7.773e+006 mg/ml). Pseudomonas aeruginosa HI1 and Bacillus subtilis 9A were highly tolerant to the acidic (pHs 2, 3) and alkaline conditions (pHs 9, 11). Moreover, when incubated with 0.3 bile salt for 24h, their surviving rates recorded 94% and 100% respectively. H 2 O 2 tolerance showed 77% surviving of Pseudomonas aeruginosa HI1 and 100% surviving of Bacillus subtilis 9A. The blood hemolysis and the antibiotics sensitivity tests confirmed the isolate's safety. The hypothesis that the isolates adhere to the lung cells, could explain the ability of the isolates and their levans to inhibit covid-19 replication.

Continue to hypothesize that honey is a storehouse of beneficial bacteria and most of these isolates are levansucrase producers. Accordingly, ten bacterial strains were isolated from different honey sources. Four honey isolates that had the highest levansucrase production were identified by the partial sequencing of the 16S rRNA gene as Achromobacter sp. (10A), Bacillus paralicheniformis (2M), Bacillus subtilis (9A), and Bacillus paranthracis (13M). The cytotoxicity of the selected isolates showed negative blood Hemolysis. Also, they are sensitive to the tested antibiotics (Amoxicillin + Flucloxacillin, Ampicilin, Gentamicin and Benzathine benzaylpencillin.). All the isolates exhibited high stability on the alkaline side (pHs 9,11) and could tolerate severe acidic conditions (29-100%). The tested isolates recorded complete tolerance to both H2O2 and the bile salt (0.3 % Oxgall powder) after 24h incubation. The cell-free supernatant of the examined strains had antifungal activities against Candida albicans with varying degrees. Also, isolates 2M and 13M showed strong activities against Staphylococcus aureus. Isolate 10A showed the highest antioxidant activity (91.45%) followed by 2M (47.37%). All isolates produced cholesterol oxidase and lipase with different levels. Besides, the four isolates reduced LDL (low-density lipoprotein) to different significant values. The cholesterol-reducing ability varied not only for strains but also for the time of incubation. The previous results recommended these isolates be used safely in solving the LDL problem.