A novel environmentally friendly 2,4,6-trinitrotoluene (TNT) based explosive

Abstract

A novel bioremediation technology has been developed. This technology involves the incorporation of a newly isolated Pseudomonas putida GG04 and Bacillus sp. SF into an explosive formulation to enhance biodegradation of TNT residues and explosives which fail to detonate due to technical problems. The incorporation of these microorganisms into the explosive did not affect the quality of the explosive in terms of detonation velocity while complete degradation of TNT moieties upon transfer in liquid media was observed after 4 days. The incorporated microorganisms sequentially reduced TNT leading to the formation of hydroxylamnidnitrotoluenes (HADNT), 4-amino-2,6-dinitrotoluenes; 2-amino-4,6-dinitrotoluenes, different azoxy compounds; 2,6-diaminonitrotoluenes and 2,4-diaminonitrotoluenes. Aminodinitrotoluenes (AMDNT) and diamninonitrotoluenes (DAMNT) constituted the predominant metabolites which steadily increased achieving 41μM and 63 μM in P. putida GG04 cultures and, 73 μM and 109 μM in Bacillus SF cultures, respectively. Although both microorganisms use NAD(P)H dependent enzymes to transform TNT, P. putida GG04 has a preference for NADPH. The accumulation of AMDNT and DAMNT was effectively prevented in the presence of guaiacol and catechol. A 89 % reduction of AMDNT and a 80 % of DAMNT was achieved in P. putida GG04 cultures, while in Bacillus sp. SF, 91% and 70 % reduction was achieved. This demonstrates that biodegradation of TNT in the presence of humic material is effective in immobilizing TNT metabolites. Addition of acetonitrile (1:4) to TNT and to its biodegradation products with sequential freezing of the samples at -20 °C was effective in concentrating and enhancing detection signals to identify TNT contaminates sites.