Benzenes, anaerobic degradation

Chakraborty R, SM O Connor, E Chan, JD Coates (2005) Anaerobic degradation of benzene, tolnene, ethylbenzene, and xylene componnds by Dechloromonas strain RCB. Appl Environ Microbiol 71 8649-8655. 

Kazumi J, ME Caldwell, JM Suflita, DR Lovley, LY Young (1997) Anaerobic degradation of benzene in diverse anoxic environments. Environ Sci Technol 31 813-818. 

It has become clear that benzoate occupies a central position in the anaerobic degradation of both phenols and alkylated arenes such as toluene and xylenes, and that carboxylation, hydroxylation, and reductive dehydroxylation are important reactions for phenols that are discussed in Part 4 of this chapter. The simplest examples include alkylated benzenes, products from the carboxylation of napthalene and phenanthrene (Zhang and Young 1997), the decarboxylation of o-, m-, and p-phthalate under denitrifying conditions (Nozawa and Maruyama 1988), and the metabolism of phenols and anilines by carboxylation. Further illustrative examples include the following ... 

Harwood, C. S and J. Gibson, Shedding light on anaerobic benzene ring degradation a process unique to prokaryotes , J. Bacteriol., 179, 301-309 (1997). 

Kuhn, E. P., Zeyer, J., Eicher, P. Schwarzenbach, R. P. (1988). Anaerobic degradation of alkylated benzenes in denitrifying laboratory aquifer columns. Applied and Environmental Microbiology, 54(2), 490-6. 

Anaerobic degradation of benzene under methanogenic conditions... 

Chaudhuri, B. K. Wiesmann, U. (1995). Enhanced anaerobic degradation of benzene by enrichment of mixed microbial culture and optimization of the culture medium. Applied Microbiology and Biotechnology, 43, 178-87. 

The vast amount of data from natural attenuation studies of petroleum hydrocarbon plumes generally supports anaerobic degradation, especially for benzene, toluene, ethylbenzene, xylenes (BTEX) under field conditions. The first-order degradation rates observed under unspecified anaerobic conditions (Suarez and Rifai, 1999) are typically one or two orders of magnitude lower than rates reported under aerobic conditions (Nielsen et al, 1996). 

The experiments carried out in the anaerobic part of the leachate plume indicate that natural attenuation of toluene and o-xylene takes place close to landhll. However, the results for ethylbenzene do not agree with the plume observations. In the case of benzene the degradation may take place at a longer distance from the landhll in more oxidized environments (Petersen, 2000). 

Degradation of Toluene and Alkyl Benzenes—The anaerobic degradation of toluene under denitrifying conditions has been extensively investigated and different pathways have emerged. 

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