Aerobic Biodegradation of 2,4,6-Trinitrotoluene (TNT) by Bacillus cereus İsolated from Contaminated Soil

Abstract

In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site.

Bioremediation of Explosive TNT by Trichoderma viride

“…Many studies have discussed the synthesis of nitro-aromatic explosives such as 2,4,6-trinitrotoluene (TNT) and 2,4,6-trinitrophenol (picric acid) and their uses for military purposes because of their highly explosive properties, thermal stability, and their insensitivity to shock and friction [8,9]. In civilian industries, these compounds are used as raw materials for the manufacturing of pesticides, herbicides, pharmaceutical products, dyes, and explosives [10,11]. Thus, the extensive use of these explosives in military applications requires the implementation of extensive handling and disposal techniques, whereas their transformation products lead to increased environmental pollution-particularly in the soil, sediment, surface, and groundwater-to levels that threaten human health and the environment [12][13][14][15][16].…”

Biodegradation of 2,4,6-Trinitrotoluene (TNT) with Bacteria Isolated from TNT-polluted Waste Pink Water

“…In a study published by Gümüşçü and Tekinay [6], it was determined that the amounts of TNT in soil and water samples taken from Elmadağ region of Ankara was in the range of 20-245 mg/ kg. In another study published by Mercimek et al [17], the amount of TNT in the sample taken from the NATO region in Izmir, Turkey was determined as 61.35 mg/L. The amount of TNT in the water sample taken for bacterial isolation was determined to be 134 mg/kg and TNT contamination of the sample was found to be between the limits specified in the literature.…”

“…SU K3 and SU K4 isolates had high TNT degradation capacity compared to SU K2 and it was determined that the isolates degraded 96 % and 93 % of the initial TNT respectively at the end of the 24-h incubation period. Since, the isolates were selected according to their ability, the resulting bacterial isolates increased cell biomass in the presence of 100 mg/L TNT and degraded the initial TNT at rates ranging from 70 % to 96 % within 24 h. Compared to previous TNT degradation studies in the literature, these degradation rates were observed to be quite high [17,30].…”

Transformation pathway of 2,4,6-trinitrotoluene by Escherichia coli nitroreductases and improvement of activity using structure-based mutagenesis

“…Many microbes, including Escherichia coli [6][7][8], Enterobacter cloacae [9], Bacillus cereus [10], Clostridium acetobutylicum [11], Clostridium thermoaceticum [12], Klebsiella sp. C1 [13], Phanerochaete chrysosporium [14], Pseudomonas sp.…”