Effect of nitrogen source on the antimicrobial activity of the bacilli air flora

Abstract

The antimicrobial activity of strainsBacillus megaterium NB-3,Bacillus cereus NB-4,Bacillus cereus NB-5,Bacillus subtilis NB-6 andBacillus circulans NB-7, previously isolated from the air flora, now in the Jerash Culture Collection (Jordan), was investigated in media containing different nitrogen sources. Maximum antimicrobial activity of strains NB-4, NB-5 and NB-6 was observed using Ca(NO3)2 as nitrogen source, (NH4)2SO4 and KNO2 strongly enhanced the antimicrobial activity of strains NB-3 and NB-7, respectively. The lowest level of the antimicrobial activity of strains NB-4 and NB-5 was observed using NaNO3. In case of strains NB-3, NB-6 and NB-7, the lowest antimicrobial activity was observed using NH4NO3, KNO3 and (NH4)2SO4 as nitrogen source, respectively.