Anaerobic catabolism

Oxygen supply in wetlands is restricted to the water column and to a thin layer of surface soil. Oxygen is also transported by wetland macrophytes to their root zone, resulting in the creation of aerobic conditions on root snrfaces (see Chapters 3 and 6 for a detailed discussion on aerobic-anaerobic interfaces in wetlands). 

Anaerobic decomposition of organic substrates is initiated by direct utilization of monomers (such as glucose) and fermentation of these monomers to simple compounds such as volatile fatty 

Dominant Processes Involved in Breakdown of Organic Substrates in Wetlands 

In the following reaction, fermentation of glucose to ethanol and lactic acid is shown  

During fermentation, selected organic compounds present in the cell are used as electron 

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The term fermentation is often used loosely by biochemical engineers. Biochemists have a more focused perspective (anaerobic) catabolism of an organic compound in which the compound serves as both an electron donor and acceptor and in which ATP is produced. 

The term fermentation was obtained from the Latin verb fervere which describes the action of yeast or malt on sugar or fruit extracts and grain. The boiling is due to the production of carbon dioxide bubbles from the aqueous phase under the anaerobic catabolism of carbohydrates in the fermentation media. The art of fermentation is defined as the chemical transformation of organic compounds with the aid of enzymes. The ability of yeast to make alcohol was known to the Babylonians and Sumerians before 6000 bc. The Egyptians discovered the generation of carbon dioxide by brewer s yeast in the preparation... 

Afring RP, BF Taylor (1981) Aerobic and anaerobic catabolism of phthalic acid by a nitrate-respiring bacterium. Arch Microbiol 130 101-104. 

Taylor BE (1983) Aerobic and anaerobic catabolism of vanillic acid and some other methoxy-aromatic compounds by Pseudomonas sp. strain PN-1. Appl Environ Microbiol 46 1286-1292. 

The anaerobic mode of protein utilization is entirely possible in theory and in practice. Oxygen is not required for protein and nitrogen catabolism until the final stages of amino acid deamination have been reached. Complete anaerobic catabolism of proteins and nitrogen compounds (to the point where the final products C02, HjO and NH3 appear) has been known for a long time in prokaryotic organisms, but in eukaryotes only in parasitic worms, which are obligate anaerobes (von Brand, 1946). However, in recent decades, anaerobic metabolism of proteins has been found in some aquatic... 

Anaerobic catabolic reactions are similar, although the electron acceptor isn t oxygen. The next example shows the fermentation of glucose to lactic acid. 

Figure 19-1 a Normal and ischemic myocardial metabolism of glucose. A total production of 36 moles of ATP results from the aerobic catabolism of 1 mole of glucose and use of NADH and FADH. in the oxidative phosphorylation process in mitochondria. When oxygen is not available, NADH and FADH levels rise and shut off the tricarboxylic acid (TCA) cycle. Pyruvate is converted to lactate. Only 2 moles of ATP are formed from anaerobic catabolism of 1 mole of glucose. (Adapted from Giuliani, E. R., ei al. Cardiology Fundamentals and Practice, 2nd ed. By permission of the Mayo Foundation, Rochester, MN.)... 

Figure 4. Possible routes for the formation of 3-mercaptoproplonate and methanethlol. I = Oxidative deamination or transamination II. Oxidative decarboxylation III. Nonoxidative decarboxylation IV. Oxidation V. Demethylation VI. Demethlolatlon VII. Aerobic/anaerobic catabolism VIII. Michael addition.

Fermentation. Anaerobic catabolism of an organic compound in which the compound serves as both electron donor and electron acceptor. 

Aerobic and anaerobic catabolic activities of heterotrophic microorganisms. 

The following is a brief summary of the comparison between aerobic and anaerobic catabolic processes ... 

Aerobic catabolism results in complete conversion of organic substrates to CO2 and H2O, resulting in the release of 100% of the energy stored in monomers. Anaerobic catabolism results in accumulation of a large proportion of the energy released from organic substrates into reduced end products. 

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