Nitroaromatic compounds - characteristics and methods of biodegradation

Nitroaromatic compounds are present in the environment mainly as industry products. They pose a serious risk to our health (often exhibiting strong mutagenic and carcinogenic effect) as well as to the environment. Most of the nitroaromatic compounds are stable due to considerable resistance to degradation and they persist in the environment for a long time. In this review, we present the current state of knowledge concerning biodegradation of nitroaromatic compounds. In the first part, general information regarding their proprieties, synthesis and sources as well as pathways of microbial aerobic or anaerobic degradation are described. In some cases microorganisms have evolved several pathways of degradation specific nitrocompound, for instance nitrobenzene, which we describe in detail. The second part of the publication focuses on environmental bioremediation of nitrocompounds. 1. Introduction. 2.2. Characteristics of aromatic nitrocompounds. 2.1. Chemical properties and synthesis nitroarenes. 2.2. Synthetic aromatic nitrocompounds. 3. The aromatic nitrocompounds in the environment. 4. Risks related to aromatic nitrocompounds. 5. Biodegradation of aromatic nitrocompounds. 5.1. Microbial degradation of aromatic compounds. 5.1.1. Aerobic degradation. 5.1.2. Reductive degradation nitroarenes. 5.1.2.1. Anaerobic digestion. 5.1.3 Degradation of nitrobenzene - an example of alternative distribution pathway. 6. Bioremediation. 6.1. Bioremediation of aromatic nitro compounds - examples of implementation. 6.1.1. Bioremediation engineering in situ. 6.1.2. Bioremediation engineering ex situ. 6.2. Limitations of the bioremediation process and strategies to overcome them. 7. Summary