Investigation of the antimicrobial and antibiofilm activities of silver nanoparticles synthesis with lacticaseibacillus rhamnosus ACS5 probiotic bacteria, prebiotics, postbiotics by the green synthesis method

In the thesis study, it was aimed to produce silver nanoparticles with Lacticaseibacillus rhamnosus ACS5 bacteria, exopolysaccharide and postbiotic by green synthesis method, to characterize the synthesized silver nanoparticles and to investigate their antimicrobial and antibiofilm activities. In addition, antioxidant (DPPH) and cytotoxicity (MTT) tests were performed on the biosynthesized nanoparticles to determine their biocompatibility. Prebiotic (PRE-AgNP), probiotic (PRO-AgNP) and postbiotic (POST-AgNP) nanoparticles were synthesized by green synthesis method. Silver nanoparticles (KİM-AgNP) were also synthesized by chemical method for comparison and characterized by UV, FTIR, XRD, SEM, Zetapotential and zeta size analysis. Antimicrobial activities of the characterized silver nanoparticles were evaluated against Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 35218, Escherichia coli ATCC 11229, Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Salmonella enteritidis ATCC 13076, Bacillus cereus ATCC 863 and Listeria monocytogenes ATCC 7644 bacteria and Candida albicans ATCC 14053 yeast were designaed with well diffusion method. PRE-AgNPs, PRO-AgNPs and POST-AgNPs showed the highest antimicrobial activity against S. epidermidis ATCC 12228 (8.32±0.11, 6.55±0.44, 6.18±0.23 mm, respectively), S. aureus ATCC 25923 (4.89±0.27, 4.96±0.11, 4.66±0.28 mm) and E. coli ATCC 11229 (3.82±0.99, 5.19±0.07, 4.38±0.96 mm). MIC and MBK values were determined to determine the antibiofilm activity of PRE-AgNP, PRO-AgNP and POST-AgNP against P. aeruginosa ATCC 27853, S. epidermidis ATCC 12228 bacteria and C. albicans ATCC 14053 yeast. The final concentration of nanoparticles that destroyed biofilms was determined as the minimum biofilm eradication value. It was determined that the synthesized silver nanoparticles had no cytotoxic effects on L929 mouse fibroblast cells and supported cell proliferation, thus being biocompatible.