Antimicrobial peptide antibiotics inhibit aerobic denitrification via affecting electron transportation and remolding

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Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids
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Antimicrobial Peptides Produced by Selective Pressure Incorporation of Non-canonical Amino Acids

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Na Wang1, Jie Gao1, Qiuying Wang1

  • 1CAS Key Laboratory of Environmental Biotechnology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China; College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China.

Journal of Hazardous Materials
|April 1, 2022
PubMed

Insights

Polymyxin B (PMB) harms aerobic denitrification, reducing nitrate removal and altering microbial metabolism. Denitrifiers adapt by forming biofilms and preferring specific carbon sources under PMB stress.

Area of Science:

  • Environmental Microbiology
  • Wastewater Treatment Technologies
  • Antimicrobial Peptide Toxicology

Background:

  • Antibiotics in wastewater can disrupt crucial microbial processes like denitrification.
  • Polymyxin B (PMB), a last-resort antibiotic, is increasingly detected in environmental samples.
  • The impact of PMB on aerobic denitrification remains poorly understood.

Purpose of the Study:

  • To investigate the effects of Polymyxin B on aerobic denitrification performance.
  • To elucidate the mechanisms by which PMB influences denitrifying bacteria.
  • To understand how PMB affects microbial metabolism and carbon source utilization.

Main Methods:

  • Aerobic denitrification experiments with varying PMB concentrations.
  • Live/dead cell staining to assess bacterial viability.
  • Transcriptome analysis to identify gene expression changes.
  • Metabolomics to analyze metabolic pathways and carbon source preference.

Main Results:

  • PMB (0.50 mg/L) significantly reduced nitrate removal efficiency from 97.4% to 85.3%.
  • PMB shifted denitrification from N2 gas production to biomass conversion and damaged bacterial membranes.
  • Key enzymes in denitrification and respiration were suppressed; denitrifiers formed thicker biofilms.
  • PMB exposure induced distinct carbon source preferences in denitrifiers.

Conclusions:

  • Polymyxin B impairs aerobic denitrification and alters microbial community functions.
  • Denitrifying bacteria develop resistance strategies, including biofilm formation and metabolic remodeling.
  • Careful consideration of carbon source selection is crucial for wastewater treatment under PMB contamination.
Keywords:
Aerobic denitrificationCarbon sourceNitrogen removalPolymyxin B

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