Molybdate reduction by Pseudomonas sp. strain DRY2.

Area of Science:

• Environmental Microbiology
• Bioremediation
• Metal Reduction

Background:

• Molybdenum is a vital trace element but can be a toxic pollutant.
• Effective bioremediation strategies are needed to address molybdenum contamination.
• Previous studies have explored microbial reduction of metals, but potent molybdenum reducers are less characterized.

Purpose of the Study:

• To isolate and characterize a novel bacterium with high molybdenum-reducing capacity.
• To identify optimal conditions for molybdenum reduction by the isolated strain.
• To assess the potential of the isolated bacterium for bioremediation applications.

Main Methods:

• Screening using a minimal salt medium with molybdate, glucose, and ammonium sulfate.
• Isolation and tentative identification of the bacterium as Pseudomonas sp. strain DRY2 using Biolog GN plates and 16S rDNA phylogeny.
• Optimization of molybdenum reduction conditions, including phosphate concentration, molybdate concentration, temperature, and pH.

Main Results:

• Pseudomonas sp. strain DRY2 was isolated and identified.
• Strain DRY2 exhibited significantly higher molybdenum blue production compared to other tested bacteria.
• Optimal conditions for molybdenum reduction were determined: 5 mmol l(-1) phosphate, 15-25 mmol l(-1) molybdate, 40°C, and pH 6.0.
• Heavy metals like chromium, copper, mercury, and lead inhibited molybdenum reduction.

Conclusions:

• A novel, highly effective molybdenum-reducing bacterium, Pseudomonas sp. strain DRY2, has been successfully isolated.
• The bacterium's characteristics indicate its strong potential for the bioremediation of molybdenum pollutants.
• Further research into the enzymatic mechanisms and large-scale application of this bacterium is warranted.