Microorganisms oxidation

Oxidation of saturated hydrocarbons. Although the initial oxidation step is chemically difficult, the tissues of our bodies are able to metabolize saturated hydrocarbons such as n-heptane slowly, and some microorganisms oxidize straight-chain hydrocarbons rapidly.30 31 Strains of Pseudomonas and of the yeast Candida have been used to convert petroleum into... 

Nitrification is the aerobic process by which microorganisms oxidize ammonium to nitrate and derive energy. It is the combination of two bacterial processes one group of organisms oxidizes ammonia to nitrite (e.g., Nitrosomonas), after which a different group oxidizes nitrite to... 

Different microorganisms oxidize sulfides to sulfoxides, usually in low yields but with high enantiomeric excesses [1046, 1047, 1068] (equation... 

Zavarzin, G.A., 1961. Symbiotic culture of a new microorganism oxidizing manganese. Microbiology, 30 343—345. 

In the first anoxic step of this sequence, anaerobic microorganisms oxidize organic material by using nitrate ions (NOj) as the oxidant. Nitrate, which occurs naturally as part of the environmental nitrogen cycle [Nielsen and MacDonald (1978)], is thereby reduced to nitrogen gas according to the following reaction ... 

The role of sulfur- and iron-oxidizing bacteria. As already noted, the rates of FeS2 and Fe(II) oxidation in environmental systems often differ substantially from the abiotic rates. Usually natural rates are much faster than laboratory abiotic rates. The reasons include inorganic catalysis and especially enzymatic oxidation by microorganisms. Oxidation of Fe(ll), for example, is catalyzed by some clays and metals, including Al, Fe, Co +, Cu, and Mn, and also HPO (Stumm and Morgan 1981). 

In comparison to all other heterotrophs, the microorganisms oxidizing methane and other Cj compounds such as methanol, have a unique metabolic pathway which involves oxygenase enzymes and thus requires O. Only aerobic methane-oxidizing bacteria have been isolated and studied in laboratory culture, yet methane oxidation in marine sediments is known to take place mostly anaerobically at the transition to the sulfate zone. Microbial consortia that oxidize methane with sulfate have in particular been studied at methane seeps on the sea floor and the communities can now also be grown in the laboratory (Boetius et al. 2000 Orphan et al. 2001 Nauhaus et al. 2002) Anaerobic methane oxidation is catalyzed by archaea that use a key enzyme related to the coenzyme-M reductase of methanogens, to attack the methane molecule (Kruger et al. 2003 see Sect. 5.1). The best studied of these ANME (ANaerobic MEthane... 

A microbial electrolysis cell is based on the concept of a microbial fuel cell (MFC) and consists of an anode and cathode chamber, a membrane that electrically separates the electrodes, and an external power supply [8] (Fig. 1). The anodic reaction is the same as in a microbial fuel cell ElectrochemicaUy active microorganisms oxidize organic compounds such as acetate, generating carbon dioxide (CO2), protons (H" ), and electrons (e ), using the anode as terminal... 

Similar products (110-112) were obtained in good yield from penicillan-ates 106 and 107 and penicillamide 108. The reaction was postulated to proceed via an acylimine, however, it was not possible to trap this intermediate with water or methanol. Free acid (113) obtained from 111 by zinc reduction was inactive against a range of microorganisms. Oxidation of 111 with m-chloroperbenzoic acid gave rise to a mixture of diastereomeric sulfoxides which were converted (acetic anhydride-DMF, 130°C) to 7,7-disubstituted deacetoxycephalosporanate 114 in 50% yield and subsequently to acid 115. The latter material displayed no antibiotic activity. 

The above microorganisms oxidize histidine to CO2 only when grown on this amino acid. This suggests that the enzyme system responsible for the degradation of histidine is inducible. 

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