Ampicillin biotransformation by a nitrifying consortium

Area of Science:

• Environmental Microbiology
• Water Treatment Technologies
• Antibiotic Resistance

Background:

• Antibiotics, including ampicillin (AMP), are emerging contaminants in wastewater.
• Ampicillin can potentially disrupt crucial wastewater treatment processes like nitrification.
• Understanding the impact of AMP on nitrifying consortia is vital for effective wastewater management.

Purpose of the Study:

• To evaluate the physiological and kinetic behavior of a nitrifying consortium exposed to varying concentrations of ampicillin (AMP).
• To determine the removal mechanisms and efficiency of AMP in a biological wastewater treatment context.
• To assess the impact of AMP on the nitrification process.

Main Methods:

• Batch culture experiments were conducted using a nitrifying consortium.
• Ampicillin concentrations tested were 10, 25, and 50 mg/L.
• Nitrification efficiency, ammonium oxidation, nitrate formation, and AMP removal were monitored.

Main Results:

• Nitrifying bacteria exhibited insensitivity to AMP across all tested concentrations, with no significant impact on nitrification efficiency or rates.
• Approximately 70.5% of AMP was removed within 24 hours via abiotic, biosorption, and biotransformation processes.
• Higher initial AMP concentrations correlated with increased biotransformation and specific AMP consumption rates.

Conclusions:

• Nitrifying bacteria are robust against ampicillin contamination in wastewater treatment.
• The biological sludge effectively removes ampicillin through a combination of mechanisms, though complete mineralization is not achieved.
• Wastewater treatment systems can potentially manage ampicillin loads while maintaining nitrification performance.