Optimization for biodegradation of 2,4,6-trinitrotoluene (TNT) by Pseudomonas putida

Area of Science:

• Environmental microbiology
• Bioremediation
• Chemical engineering

Background:

• 2,4,6-trinitrotoluene (TNT) is a persistent environmental pollutant.
• Bioremediation using microorganisms offers a sustainable solution for TNT-contaminated sites.
• Optimizing environmental factors is crucial for efficient microbial degradation of TNT.

Purpose of the Study:

• To determine optimal environmental conditions for the biodegradation of TNT by Pseudomonas putida KP-T202.
• To enhance the commercial feasibility and reduce the time required for TNT biodegradation.
• To identify key intermediates formed during the degradation process.

Main Methods:

• Isolation and identification of a TNT-degrading bacterial strain, Pseudomonas putida KP-T202.
• Systematic variation of environmental parameters including temperature, pH, and nutrient concentrations (corn steep liquor, NH4Cl, Tween 80).
• Monitoring TNT degradation kinetics and identifying intermediate compounds using analytical techniques.

Main Results:

• Complete degradation of 100 mg/l TNT within 15 hours under aerobic conditions.
• Optimal conditions identified: 30°C, pH 7, 1% corn steep liquor (CSL), 0.025% NH4Cl, and 0.1% Tween 80.
• A high reaction rate constant of 0.348 h⁻¹ was achieved under optimal conditions. Intermediates identified: 2-amino-4,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, 2,4-dinitrotoluene, and 2,6-dinitrotoluene.

Conclusions:

• The identified optimal conditions significantly enhance the efficiency of Pseudomonas putida KP-T202 for TNT biodegradation.
• These findings provide a basis for developing large-scale bioreactor systems for treating TNT-contaminated wastewater and soil.
• The study contributes to sustainable environmental management strategies for explosive-contaminated sites.