Phosphate uptake and release by Acinetobacter johnsonii in continuous culture and coupling of phosphate release to heavy metal accumulation

J Ind Microbiol Biotechnol. 2001 Jun;26(6):333-40. doi: 10.1038/sj.jim.7000139.


A strain of polyphosphate-synthesizing, phosphate-releasing Acinetobacter johnsonii was isolated from a wastewater treatment plant operating enhanced biological phosphate removal (EBPR) and was used to remove La(3+) from solution via precipitation of cell-bound LaPO(4). The effect of repeated aerobic-anaerobic cycles on the carbon and phosphate metabolism of the organism was studied in attempts to promote increased phosphate flux using a three-stage, continuous bioreactor comprising aerobic, anaerobic and settling vessels. The bioreactor was operated in two modes: In flow-through mode, cells were grown aerobically with acetate as the sole carbon source, promoting excess phosphate uptake (up to 5.0 mmol/l=3.0 mmol/g protein). Cells were diluted into the anaerobic vessel where phosphate was released (up to 1.0 mmol/l=0.3 mmol/g protein), and thence to waste. The system was initially operated to steady state in flow-through mode, then switched to recycle mode. Here the anaerobic vessel output passed to a settling vessel from which settled cells were returned to the aerobic vessel. Carbon source (acetate) was supplied only to the anaerobic vessel; increased anaerobic acetate uptake was observed during recycle, which was sustained when the system was returned to flow-through mode and was related to increased cellular lipid inclusions by flow cytometry and electron microscopy. These phenomena may represent adaptation of cells to aerobic-anaerobic cycling with aerobic carbon/energy limitation. Addition of La(3+) to the anaerobic vessel during recycle mode promoted removal of 95% of the La(3+) from a 0.1 to 0.3 mM (14-42 ppm) solution at the expense of biogenic phosphate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / metabolism
  • Acinetobacter / growth & development
  • Acinetobacter / metabolism*
  • Acinetobacter / ultrastructure
  • Aerobiosis
  • Anaerobiosis
  • Biodegradation, Environmental
  • Biomass
  • Bioreactors
  • Flow Cytometry
  • Hydrogen-Ion Concentration
  • Industrial Waste
  • Lanthanum / metabolism*
  • Metals, Heavy / metabolism*
  • Microscopy, Electron
  • Nitrates / metabolism
  • Phosphates / metabolism*
  • Water Purification


  • Acetates
  • Industrial Waste
  • Metals, Heavy
  • Nitrates
  • Phosphates
  • Lanthanum