Biomass relationship to growth and phosphate uptake of Pseudomonas fluorescens, Escherichia coli and Acinetobacter radioresistens in mixed liquor medium.

The ability of Pseudomonas fluorescens, Escherichia coli and Acinetobacter radioresistens to remove phosphate during growth was related to the initial biomass as well as to growth stages and bacterial species. Phosphate was removed by these bacteria under favourable conditions as well as under unfavourable conditions of growth. Experiments showed a relationship between a high initial cell density and phosphate uptake. More phosphate was released than removed when low initial cell densities (10(2)-10(5) cells ml-1) were used. At a high initial biomass concentration (10(8) cells ml-1), phosphate was removed during the lag phase and during logarithmic growth by P. fluorescens. Escherichia coli, at high initial biomass concentrations (10(7) cells ml-1), accumulated most of the phosphate during the first hour of the lag phase and/or during logarithmic growth and in some cases removed a small quantity of phosphate during the stationary growth phase. Acinetobacter radioresistens, at high initial cell densities (10(6), 10(7) cells ml-1) removed most of phosphate during the first hour of the lag phase and some phosphate during the stationary growth phase. Pseudomonas fluorescens removed phosphate more than A. radioresistens and E. coli with specific average ranges from 3.00-28.50 mg L-1 compared to average ranges of 4.92-17.14 mg L-1 for A. radioresistens and to average ranges of 0.50-8.50 mg L-1 for E. coli.