Oxygen toluene biodegradation

Calculation of the Requirements in Oxygen and Macronutrients (N, P) for the Aerobic Biodegradation of Toluene... 

Anaerobic conditions often develop in hydrocarbon-contaminated subsurface sites due to rapid aerobic biodegradation rates and limited supply of oxygen. In the absence of O, oxidized forms or natural organic materials, such as humic substances, are used by microorganisms as electron acceptors. Because many sites polluted by petroleum hydrocarbons are depleted of oxygen, alternative degradation pathways under anaerobic conditions tend to develop. Cervantes et al. (2001) tested the possibility of microbially mediated mineralization of toluene by quinones and humus as terminal electron acceptors. Anaerobic microbial oxidation of toluene to CO, coupled to humus respiration, was demonstrated by use of enriched anaerobic sediments (e.g., from the Amsterdam petroleum harbor). Natural humic acids and... 

Biodegradation. Nitrosubstituted compounds are subject to a variety of degradative processes. Under anaerobic conditions TNT is readily reduced to the corresponding aromatic amines and subsequently deaminated to toluene. As shown in the section on hydrocarbons, Llie latter can be mineralized under anaerobic conditions, leading to the potentially complete mineralization of TNT in the absence of oxygen. 

It has recently been found that obligately anaerobic microbial consortia can mineralize many recalcitrant chemicals (toluene, chloroform, benzene, chlorophenols, etc.) that had been considered essentially nonbiodegradable in the absence of oxygen (19, 20, 21). Extensive work at the University of Idaho with obligately anaerobic microbial consortia indicates that these systems are capable of complete biodegradation of nitroaromatic pollutants. Work with 2-.s c-butyl-4,6-dinitrophenol (dinoseb) has shown complete fermentation of this nitroaromatic pollutant in soils by anaerobic consortia without buildup of aromatic biotransformation products (16, 17). Similar results were observed with a variety of nitro-toluenes and munitions residues, including TNT and trimethylenenitramine (RDX) under appropriately controlled conditions (12, 13). In the work with TNT and RDX, hydroxyaro-... 

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