Cd. Boswell et al., Phosphate uptake and release by Acinetobacter johnsonii in continuous culture and coupling of phosphate release to heavy metal accumulation, J IND MIC B, 26(6), 2001, pp. 333-340
Citations number
39
Categorie Soggetti
Biotecnology & Applied Microbiology",Microbiology
Journal title
JOURNAL OF INDUSTRIAL MICROBIOLOGY & BIOTECHNOLOGY
A strain of polyphosphate-synthesizing, phosphate-releasing Acinetobacter j
ohnsonii was isolated from a wastewater treatment plant operating enhanced
biological phosphate removal (EBPR) and was used to remove La3+ from soluti
on via precipitation of cell-bound LaPO4. The effect of repeated aerobic-an
aerobic cycles on the carbon and phosphate metabolism of the organism was s
tudied 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 t
o steady state in flow-through mode, then switched to recycle mode. Here th
e anaerobic vessel output passed to a settling vessel from which settled ce
lls were returned to the aerobic vessel. Carbon source (acetate) was suppli
ed only to the anaerobic vessel; increased anaerobic acetate uptake was obs
erved during recycle, which was sustained when the system was returned to f
low-through mode and was related to increased cellular lipid inclusions by
flow cytometry and electron microscopy. These phenomena may represent adapt
ation of cells to aerobic-anaerobic cycling with aerobic carbon/energy limi
tation. Addition of La3+ to the anaerobic vessel during recycle mode promot
ed removal of 95% of the La3+ from a 0.1 to 0.3 mM (14-42 ppm) solution at
the expense of biogenic phosphate.