Characterization of some Bacillus sp. strains and their bioactive metabolites, evaluation of antifungal, antibacterial and antioxidant activity

In this study, it is aimed to determine the antimicrobial and antioxidant activities of Bacillus sp. strains isolated from healthy honey bees (Apis mellifera) and these strains metabolites produced in the growth medium under culture conditions. Characterization of Bacillus sp. strains; microscopy, resistance to environmental and physical conditions, biochemical tests, antibiograms, antibacterial and antifungal activities were tested. It was determined that Bacillus sp. strains achieved optimum growth in pH 8.0, 35 °C, and in conditions containing 5% salt and 20% glucose. Antimicrobial activity against Gram (+) bacteria and some fungi was observed in the supernatants and extracts of the strains. After DNA isolation, according to the 16S rRNA sequence analysis, it was determined that it was similar to Bacillus sp. Ethyl acetate was used in purification and experiments, since the efficiency of ethyl acetate extraction was higher when extraction was performed with different solvents. The chemical and structural properties of the 4 purified substances were determined by NMR analysis. It was determined that these pure substances (C7H13NO, C12H22O11, C18H34O, C8H11NO) did not have antifungal activity, C12H22O11 and C18H34O substances had similar antibacterial (E. coli, P. aeruginosa, B. cereus, E. faecalis, S. pyogenes) activity. It was determined that C7H13NO was effective only against E. coli and S. pyogenes, while C8H11NO was effective against all bacteria. It was determined that Bacillus sp. strains had antioxidant activity in the liquid medium in which they were grown.