Neutralization of the antimicrobial effect of glyphosate by humic acid in vitro

• Glyphosate has an antimicrobial effect on intestinal microorganisms.
• Glyphosate can disturb the bacterial community due to differences in sensitivity between microorganisms.
• Humic acids neutralized the antimicrobial effect of glyphosate.

In the present study, the neutralization ability of the antimicrobial effect of glyphosate by different humic acids was investigated. The minimal inhibitory concentrations of glyphosate for different bacteria such as Bacillus badius, Bifidobacterium adolescentis, Escherichia coli, E. coli 1917 strain Nissle, Enterococcus faecalis, Enterococcus faecium, Salmonella enteritidis and Salmonella typhimurium were determined in the presence or absence of different concentrations of humic acid (0.25, 0.5 and 1.0 mg mL−1). Our findings indicated that humic acids inhibited the antimicrobial effect of glyphosate on different bacteria. This information can help overcome the negative impact of glyphosate residues in feed and water.