Comparison of 2, 4, 6-trinitrotoluene (TNT) contaminated water biological treatment by various microorganisms

Due to carcinogenic, mutagenic and toxic properties of 2,4,6-trinitrotoluen (TNT) in military industries wastewater, treatment of TNT wastewater is crucial. The aim of this work is to identify the superior organism for TNT remediation among seven microorganisms reported as being effective in aromatic hydrocarbon biodegradation. Mycelial growth of all fungal strains namely Penicillium purpurogenome, Phanerochaete chrysosporium and Aspergillus terrus was examined at 50ppm TNT, A. terrus showing the highest growth rate. To assess the inhibitory effect of TNT on fungal growth, TNT at 100ppm was used where only A. terrus could tolerate this concentration. This is the first report on fungal growth at this high TNT concentration. Among the tested bacteria in aerobic cultures (TNT at 100ppm supplemented with 0.5% glucose), Pseudomonas putida was found as a superior candidate for TNT remediation (>80% removal during 24h). The effect of various co-substrates on growth of P. putida was also investigated leading to glucose as the best co-substrate. In addition, to evaluate the role of surfactant on bioavailability of TNT in water, 0.1% Tween80 was used resulting in a 10h decrease in biodegradation time compared to the culture without surfactant.

Keywords:

Biotransformation , Explosives , Pseudomonas Putida , TNT , Wastewater Treatment