Detection of Fungal Capabilities to Metabolize 2,4,6-Trinitrotoluene Using Cyclic Voltammetry

J. E. Liquet y González, J. Castellanos, I. Cortez, V. Miranda, R. Padilla, F. Morales, C. Vega, S. Hernandez, C. Ríos-Velazquez

Author address: 

Univ. of Puerto Rico-Mayagüez, Mayagüez, Puerto Rico


2,4,6-Trinitrotoluene (TNT) is a man-made explosive used in military shells, bombs, and grenades, in industrial uses, and in underwater blasting. TNT is present in the environment throughout diverse locations, and also known to accumulate in animals and plants. Although its effects on human health are not completely understood, the Environmental Protection Agency, has classified it as a possible human carcinogen. Biodegradation is regarded as an option to clean up many environmental pollutants. However, there is a need for TNT biodegradation experiments using fungi where the metabolic activity can be easily detected. Cyclic voltammetry (CV) is an electrochemical technique that uses an alternating current, oxidizes and reduces molecules, producing a detectable signal. The main focus of this research is the use of CV as an effective technique to detect the TNT degradation capabilities of a fungal bioprospect isolated in Puerto Rico. Spores suspensions of the prospective TNT-degrader, Aspergillus sp., were spreaded on Potato Dextrose Agar, and after 7 days of incubation, 5mm fungal disks were placed in tubes with Bushnell-Haas broth with 68ppm of TNT for 58 days. After applying CV for TNT, three oxidized peaks were found with the increasing current (called Peak 1, 2 and 3) and one that was reduced (Peak 4). In the first five days of incubation, the TNT concentration decreased almost 10ppm in average for Peak 1 and Peak 4. After 58 days of incubation, the TNT concentration had decreased almost 20 ppm on average for the mentioned peaks. For Peak 2 and 3 we did not found a drastic decrease in concentration, only a reduction of 8ppm on average after 58 days of incubation. There was no noticeable change in the fungus morphology after 58 days of incubation with exposure to TNT, determined by using a scanning electron microscope. Further studies to determine the biodegradation product are underway. These findings demonstrate not only that the fungal bioprospect is metabolizing TNT, but also confirm the use of a feasible method to detect metabolic activity in biological systems. The results will allow the discovery of enzymes with potential industrial application and could propose a cost-effective mechanism to biodegrade environmental TNT into a less-hazardous compounds.

abstract No: 


Full conference title: 

ASM Microbe 2016
    • ASM microbe 1st (2016)