Biodegradation of dimethylterephthalate by Comamonas acidovorans D-4

Area of Science:

• Environmental Microbiology
• Biotechnology
• Bioremediation

Background:

• Petrochemical wastewater often contains recalcitrant organic pollutants like dimethylterephthalate (DMT).
• Effective bioremediation strategies are crucial for mitigating environmental contamination from industrial activities.

Purpose of the Study:

• To isolate and characterize a microbial strain capable of utilizing DMT as a sole carbon source.
• To investigate the degradation kinetics and metabolic activity of the isolated strain.
• To assess the potential of the strain for petrochemical pollution abatement.

Main Methods:

• Isolation of bacteria from activated sludge of a petrochemical wastewater treatment plant.
• Cultivation of isolates using DMT as the sole carbon source.
• Monitoring of bacterial growth, DMT utilization, and esterase activity.
• Analysis of degradation byproducts, including terephthalic acid.

Main Results:

• Comamonas acidovorans D-4 was isolated and demonstrated the ability to utilize DMT (up to 0.5% w/v) as the sole carbon source, with near-complete utilization within 72 hours.
• A direct correlation was observed between bacterial growth, DMT consumption, and cell-associated esterase activity.
• Extracellular esterase activity was detected in cell-free broth, and terephthalic acid was identified as an extracellular accumulation product during DMT degradation.
• The organism exhibited growth on various phthalate esters and phthalic acids, with significantly higher growth observed on phthalic acids.

Conclusions:

• Comamonas acidovorans D-4 possesses the metabolic capability to degrade DMT, a key component in petrochemical waste.
• The esterase activity and terephthalic acid accumulation provide insights into the degradation pathway.
• This bacterium holds significant promise for the bioremediation of DMT-contaminated industrial wastewater.