Abstract The dinitrotoluene (DNT) isomers 2,4- and 2,6-DNT are highly toxic compounds, and their occurrence in groundwater and soils is a widespread problem mainly due to the explosive manufacturing industry and from the commercial production
of polyurethane foam. Moreover, these compounds have mutagenic and carcinogenic properties making them a great hazard to the public health. Thus, their removal from the environment is paramount, and bioremediation strategies can be
applied for the environmental cleanup. Pure cultures of microorganisms able to degrade at least 2,4-DNT have been recently isolated as well as a consortium and different plant species. The pure cultures are an Arthrobacter strain isolated from crude oil-contaminated soil, a Rhodococcus pyridinovorans NT2, and Shewanella marisflavi EP1, while the consortium named UHasselt Sofie 3 (UHS3) was formed by Burkholderia HC114, Variovorax paradoxus VM685, Bacillus, Pseudomonas
mandelii HC88, and Ralstonia HC90. These microorganisms perform the degradation of the dinitrotoluenes in aerobic conditions except the marine strain Shewanella marisflavi. The plant species able to grow in the presence of 2,4-DNT and proposed for phytoremediation are hemp, flax, sunflower, and mustard. The intermediates reported in the majority of successful biodegradation studies are 4-methyl-5-nitrocatechol (4M5NC) and 2-hydroxy-5-methylquinone (2H5MQ) under aerobic conditions, while 2,4-diaminotoluene is obtained as an end product via the formation of 2-amino-4-nitrotoluene (2A4NT) and 4-amino-2-nitrotoluene (4A2NT) under anaerobic conditions. These microorganisms add to the growing number of isolates with the ability to degrade these types of compounds since strain DNT was
isolated. This mini-review focuses on the microorganisms involved in the degradation of the dinitrotoluene isomers 2,4- and 2,6-DNT in recent years. Information related to the degradation of these contaminants is critical to understanding and predicting
their fate in the environment. |
