Aerobic and anaerobic conditions

Carbamates such as Aldicarb undergo degradation under both aerobic and anaerobic conditions. Indeed the oxidation of the sulfur moiety to the sulfoxide and sulfone is part of the activation of the compound to its most potent form. Subsequent aerobic metaboHsm can completely mineralize the compound, although this process is usually relatively slow so that it is an effective iasecticide, acaricide and nematocide. Anaerobically these compounds are hydrolyzed, and then mineralized by methanogens (61). 

Aerotolerant anaerobes Microbes that grow under both aerobic and anaerobic conditions, but do not shift from one mode of metabolism to another as conditions change. They obtain energy exclusively by fermentation. 

Cyanidin 3-glucoside and cyanidin 3-rutinoside were degraded at 100°C in weak acidic solutions at pH range 1 to 4 under aerobic and anaerobic conditions." The degradation revealed that cyanidin 3-glucoside was more stable under both conditions." ... 

The operation of these hydrolytic reactions is independent of the oxygen concentration of the system so that—in contrast to biotic degradation and transformation—these reactions may occur effectively under both aerobic and anaerobic conditions. 

In contrast, cells grown anaerobically with nitrate and vanillate were able to oxidize vanillate under both aerobic and anaerobic conditions. The cells were also able to demethylate a much wider spectrum of aromatic methoxy compounds under anaerobic conditions than under aerobic conditions (Taylor 1983). Such subtleties should be clearly appreciated and taken into consideration in evaluating the degradative potential of comparable organisms under different physiological conditions. 

Reduction is an important reaction under both aerobic and anaerobic conditions. Reductases mediate a wide variety of reactions that are summarized briefly here, and have been discussed in detail in Part 2 dealing with electron acceptors and further in Part 5 with metalloenzymes. The reductases that are components of the aromatic dioxygenases and that are involved in the aerobic bacterial degradation of aromatic hydrocarbons are noted parenthetically in Chapter 8, Parts 1 and 2. 

Thauera sp. strain DNT-1 is able to degrade toluene under aerobic conditions mediated by a dioxygenase, and under denitrifying conditions in the absence of oxygen by the anaerobic benzylsuccinate pathway (Shinoda et al. 2004). Whereas the tod genes were induced under aerobic conditions, the bss genes were induced under both aerobic and anaerobic conditions. 

Although application of 0 has been less frequent, it has been used effectively to determine the source of oxygen and the number of oxygen atoms incorporated during metabolism of xenobiotics under both aerobic and anaerobic conditions. Some typical examples are given below ... 

A corrinoid pathway for Cj halides, which operates under both aerobic and anaerobic conditions... 

Benzene is one of a group of related aromatic monocyclic hydrocarbons (BTEX—benzene, toluene, ethylbenzene, and xylene), and since these are water soluble, there has been concern for their dissipation and persistence in groundwater under both aerobic and anaerobic conditions. Although aerobic growth at the expense of benzene was established many years ago, the pathway for its degradation was established only much later. The aerobic degradation of benzene by bacteria is... 

Bregnard TP-A, P Hohener, A Haner, J Zeyer (1996) Degradation of weathered diesel fuel by microorganisms from a contaminated aquifer in aerobic and anaerobic conditions. Environ Toxicol Chem 15 299-307. 

The degradation of a structurally wide range of ethers under both aerobic and anaerobic conditions is covered in a review (White et al. 1996), which should be consulted for details, particularly of polyethers. 

Ball HA, M Reinhard, PL McCarty (1989) Biotransformation of halogenatednonhalogenated octylphenol polyethoxylate residues under aerobic and anaerobic conditions. Environ Sci Technol 23 951-961. 

A group at the Bach Institute in Moscow was able to isolate a flavine pigment (an isoalloxacine derivative) from the polymer obtained by heating a mixture of three amino acids (glutamic acid glycine lysine = 8 3 1) this exhibited photochemical acivity (e.g., redox reactions such as electron transfer to acceptors with lower Eo values) under both aerobic and anaerobic conditions (Kolesnikov and Kritsky, 1999). 

This chapter has three main objectives firstly, to summarize the behavior of emerging contaminants during sewage treatment because it determines their transfer to biosolids secondly, to provide a comprehensive overview of the current knowledge regarding the occurrence of these pollutants in sludge. Finally, the potential routes for the elimination of emerging contaminants in both aerobic and anaerobic conditions are discussed. 

Joss A, Andersen H, Temes T, Richie PR, Siegrist H (2004) Removal of estrogens in municipal wastewater treatment under aerobic and anaerobic conditions consequences for plant optimization. Environ Sci Technol 38 3047-3055... 

Kaiser, J.-P. Feng, Y., and Bollag, J.-M., Microbial Metabolism of Pyridine, Quinoline, Acridine, and Their Derivatives Under Aerobic and Anaerobic Conditions. Microbiological Reviews, 1996. 60(3) pp. 483-498. 

Chemical weathering of minerals during pedogenesis can be enhanced by microbial activity by a factor as high as 106 (Kurek 2002). Microorganisms can dissolve minerals by direct and indirect actions under aerobic and anaerobic conditions (Robert and Berthelin 1986 Ehrlich 2002 Kurek 2002). In some cases of attack, the microorganisms may be dispersed in the soil solution in others, they may grow in biofilms on the surface of susceptible minerals. 

Compeau and Bartha [80] have discussed the abiotic methylation of mercuric ion and mercuric ion sea salt anion complexes to methylmercury by methylcyanocobalamin in seawater and saline sediments under aerobic and anaerobic conditions. 

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