Toxic effects of some benzamines on the growth of Azotobacter vinelandii and other bacteria

Benzamines are the major aromatic amines used in industry and can also be released from azo dyes, which are widely used in the textile, paper- making, and food industries. The toxicity of 10 benzamines was tested by the well diffusion assay technique against 18 common bacterial species including the nitrogen-fixing bacterium Azotobacter vinelandii. p-Phenylenediamine was found to be inhibitory to the growth of Aeromonas hydrophila and Pseudomonas fluorescens. o-Phenylenediamine was inhibitory to Escherichia coli, Klebsiella pnemoniae, Salmonella enteritidis, and Shigella sonnei. 2,5- Diaminotoluene was inhibitory to the growth of P. fluorescens and Streptococcus mitis. The growth of A. vinelandii was inhibited by p- phenylenediamine and 2,5-diaminotoluene in the well diffusion assay. p- Nitroaniline was also found to be inhibitory to the growth of A. vinelandii in Burk's nitrogen-free medium. The nitrogenase activity of A. vinelandii was inhibited by p-phenylenediamine, 2,5-diaminotoluene, p-nitroaniline, 2- nitro-p-phenylenediamine, 3-nitro-o-phenylenediamine, and 4-nitro-o- phenylenediamine. Because many of these organisms are common soil and aquatic bacteria, the accumulation of these benzamine compounds in the environment may have an adverse impact on soil biochemical activities.