TNT and related nitroaromatic compounds have entered the soil and groundwater at many munitions manufacturing and storage sites, including those operated under contract to the Department of Defense. This project, sponsored by the US Army Construction Engineering Research Lab in Champaign, IL, is an effort to solve this problem. TNT, and related compounds and breakdown products are especially harmful to aquatic organisms such as algae, small invertebrate animals and fish. In humans, TNT itself can cause headaches, weakness, anemia and liver injury. Enzymes, which are proteins obtained from bacteria or other biosources, catalyze or accelerate chemical reactions in nature.
Isolated enzymes offer several advantages in bioremediation over the bacteria themselves.
For example, enzyme catalyzed reactions are more efficient and controlled and do not contaminate the water with other compounds such as bacterial metabolites. Enzymatic degradation of TNT is likely to be more complete in rendering the compound harmless than bacterial remediation or phytoremediation, which requires the plant material to be combusted after TNT and its metabolites are accumulated by the plants. NECi has developed specialized skills in handling enzymes for bioremediation systems. Contaminated water is pumped over the enzyme particles and the toxic compounds in the water are degraded by enzymatic catalysis. To provide the energy for driving the degradation process, the bioreactor is supplied with electric current which reaches the reaction center via a dye molecule also attached to the enzyme particles.