Kinetics of a chlorate-accumulating, perchlorate-reducing bacterium

Area of Science:

• Environmental microbiology
• Bioremediation

Background:

• Perchlorate-reducing bacteria (PCRB) are crucial for bioremediation.
• Dechlorosoma sp. HCAP-C exhibits unique chlorate accumulation during perchlorate reduction.

Purpose of the Study:

• Determine kinetic parameters for perchlorate and chlorate reduction by Dechlorosoma sp. HCAP-C.
• Investigate the novel chlorate accumulation behavior and its implications for kinetics.

Main Methods:

• Batch tests were conducted with varying initial perchlorate concentrations (200-1400 mg/L).
• A competitive inhibition model was used to determine kinetic parameters for perchlorate reduction.
• Kinetic parameters for chlorate reduction were also quantified.

Main Results:

• Dechlorosoma sp. HCAP-C accumulated chlorate at 20% of initial perchlorate concentrations (41-279 mg/L).
• Maximum specific degradation rate (qmaxP) for perchlorate was 11.5 mg/mg DW-d, with a half-maximum rate constant (KP) of 193 mg/L.
• Maximum specific degradation rate (qmaxC) for chlorate was 8.3 mg/mg DW-d, with a half-maximum rate constant (KC) of 58.3 mg/L.

Conclusions:

• High KP values suggest Dechlorosoma sp. HCAP-C is less effective at low perchlorate concentrations.
• The bacterium's high qmaxP and potential for syntrophic relationships indicate significant potential at high perchlorate concentrations.