Analysis of extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis-UBAF process for the elimination of high-level ciprofloxacin

Chemosphere. 2018 Feb:193:645-654. doi: 10.1016/j.chemosphere.2017.11.056. Epub 2017 Nov 14.

Abstract

Extracellular polymeric substances (EPS) and ciprofloxacin-degrading microbial community in the combined Fe-C micro-electrolysis and up-flow biological aerated filter (UBAF) process for the treatment of high-level ciprofloxacin (CIP) were analyzed. The research demonstrated a great potential of Fe-C micro-electrolysis-UBAF for the elimination of high-level CIP. Above 90% of CIP removal was achieved through the combined process at 100 mg L-1 of CIP loading. In UBAF, the pollutants were mainly removed at 0-70 cm heights. Three-dimensional fluorescence spectrum (3D-EEM) was used to characterize the chemical structural of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) extracted from biofilm sample in UBAF. The results showed that the protein-like substances in LB-EPS and TB-EPS had no clear change in the study. Nevertheless, an obvious release of polysaccharides in EPSs was observed during long-term exposure to CIP, which was considered as a protective response of microbial to CIP toxic. The high-throughput sequencing results revealed that the biodiversity of bacteria community became increasingly rich with gradual ciprofloxacin biodegradation in UBAF. The ciprofloxacin-degrading microbial community was mainly dominated by Proteobacteria and Bacteroidetes. Microorganisms from genera Dechloromonas, Brevundimonas, Flavobacterium, Sphingopyxis and Bosea might take a major role in ciprofloxacin degradation. This study provides deep theoretical guidance for real CIP wastewater treatment.

Keywords: Ciprofloxacin; Ciprofloxacin-degrading microbial community; Extracellular polymeric substances (EPS); Fe-C micro-electrolysis-UBAF.

MeSH terms

  • Bacteria / metabolism*
  • Biodegradation, Environmental*
  • Biodiversity
  • Biofilms
  • Ciprofloxacin / metabolism*
  • Electrolysis
  • Polymers / chemistry
  • Polysaccharides
  • Polysaccharides, Bacterial / chemistry*
  • Sewage / chemistry
  • Wastewater / chemistry
  • Wastewater / microbiology

Substances

  • Polymers
  • Polysaccharides
  • Polysaccharides, Bacterial
  • Sewage
  • Waste Water
  • Ciprofloxacin