Efficient phosphate accumulation in the newly isolated Acinetobacter junii strain LH4

Area of Science:

• Environmental Microbiology
• Water Remediation Technologies
• Bacterial Physiology

Background:

• Phosphate accumulation by bacteria is a cost-effective and eco-friendly method for remediating eutrophic waters.
• Sludge from high-nutrient environments is a potential source for identifying effective phosphate-removing bacteria.

Purpose of the Study:

• To isolate and characterize a bacterial strain with high phosphate (PO43-) removal capabilities from sludge.
• To evaluate the efficiency and optimal conditions for phosphate removal by the identified strain.

Main Methods:

• Isolation of bacterial strains from sludge with high nutrient loads.
• Identification of the most effective strain (LH4) using physiological, biochemical, and molecular analyses.
• Toluidine blue staining to confirm phosphate-accumulating organism (PAO) status.
• Optimization of growth and removal conditions (carbon/nitrogen sources, C:N ratio, pH, temperature, inoculation concentration, shaking speed).

Main Results:

• Strain LH4 identified as Acinetobacter junii, a potent PAO.
• Achieved 99% phosphate removal efficiency under optimized conditions (anaerobic pre-incubation followed by aerobic growth).
• Optimal conditions include specific carbon/nitrogen sources, C:N ratio of 5:1, pH 6, 30°C, 3% inoculation, and 100 rpm shaking speed.
• Relative phosphate removal capacity ranged from 0.67 to 3.84 mg L-1 h-1, placing it among the top reported PAOs.

Conclusions:

• Acinetobacter junii strain LH4 is a highly efficient phosphate-accumulating bacterium with significant potential for eutrophic water remediation.
• The identified optimal conditions provide a basis for large-scale application of this strain.
• Further investigation into the large-scale application of this bacterial strain is warranted.