Hydrocarbons microbial oxidation

Experimental procedures have been described in which the desired reactions have been carried out either by whole microbial cells or by enzymes (1—3). These involve carbohydrates (qv) (4,5) steroids (qv), sterols, and bile acids (6—11) nonsteroid cycHc compounds (12) ahcycHc and alkane hydroxylations (13—16) alkaloids (7,17,18) various pharmaceuticals (qv) (19—21), including antibiotics (19—24) and miscellaneous natural products (25—27). Reviews of the microbial oxidation of aUphatic and aromatic hydrocarbons (qv) (28), monoterpenes (29,30), pesticides (qv) (31,32), lignin (qv) (33,34), flavors and fragrances (35), and other organic molecules (8,12,36,37) have been pubflshed (see Enzyp applications, industrial Enzyt s in organic synthesis Elavors AND spices). 

Patel RN, CT Hou, AI Laskin, A Felix (1982) Microbial oxidation of hydrocarbons properties of a soluble monooxygenase from a facultative methane-utilizing organisms Methylobacterium sp. strain CRL-26. Appl Environ Microbiol 44 1130-1137. 

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... 

Laboratory studies with petroleum and petroleum fractions. The first report of microbial oxidation of sulfur heterocycles was published by Walker et al. (28). Using computerized mass spectrometry (MS) to analyze the residual oil extracted from aerobically-grown mixed cultures, they observed losses of 40% of the dibenzothiophenes and 50% of the naphthobenzothiophenes. They concluded that the sulfur-containing aromatics were approximately twice as resistant to microbial degradation as their hydrocarbon analogues. 

Acyclic tritetpenes can be considered as aliphatic hydrocarbons and are a iydroxylated by a numbo of microorganisms. The microbial oxidation of a varied of acyclic terpenoid hydrocarbons has been investigated by Nakajima, and aldrough terminal alcohols can obtained, for example pristanol (39) from pristane (38 equation 11), further oxidation can also occur. 

Van der Linden AC, Thijsse GJE. 1965. The mechanisms of microbial oxidations of petroleum hydrocarbons. In Nord FF, ed. Advances in enzymology and related subjects of biochemistry. Volume XXVII. New York, NY Interscience Publishers, 469-546. 

Carbonate cement haloes associated with hydrocarbon pools are well documented, and commonly attributed to the microbial oxidation of crude oil or methane in different geological settings (Gould Smith, 1978 Smith, 1978 Faber Stahl, 1984 Oehler Sternberg, 1984 Hovland et al., 1987 O Brien Woods, 1995). However, a number of observations point towards this type of precipitation mechanism not being appropriate in the context of the Angel Field and Gidgealpa Field areas ... 

The organic carbon sources at seeps (methane, petroleum, other hydrocarbon gases, solid gas hydrates) are derived primarily from accumulated sedimentary organic carbon and thus are photosynthetic in origin (Tunnicliffe etal., 2003). In addition, microbial oxidation of reduced compounds at/or above the seafloor requires photosynthetically produced oxygen. Thus, while these ecosystems are primarily based on chemosynthesis (Aharon, 2000), they are not completely independent from photosynthesis-dominated pelagic ecosystems. 

Assuming that the yield is 100% with respect to hydrocarbon and 50% with respect to glucose, the process with alkanes requires 2.6 times more oxygen for the production of the same quantity of cells. In the microbial oxidation of hydrocarbons, cases of limited oxygen supply have been reported (Klug and Markovetz, 1969 Yamada et al, 1968). 

A number of microbial reagents have been used for successful oxidation of steroids, isoprenoids, alkaloids, hydrocarbons and other type of molecules. A number of reviews and monographs are available. Here we have given few cases which offer synthetic utility because they can afford excellent yield or they give single product that is inaccessible by other methods. Following are some typical microbial oxidations ... 

Fatty acids derived from alkanes have received considerable attention as surfactants. Rehm and Reiff 1981 have published a detailed list of fatty acids resulting from the microbial oxidation of alkanes. The hydrophUic-lipophilic balance (HLB) of fatty acids is clearly related to the length of the hydrocarbon chain. For lowering surface and interfacial tensions, the most active saturated fatty acids are in the range of C-12 to C-14. In addition to straight-chain fatty adds, microorganisms produce... 

Bacterial utilization and degradation of hydrocarbons. The oxidation of higher hydrocarbons under aerobic conditions by Micrococcus, Pseudomonas, Mycobacterium, and Nocardia is an important environmental process by which petroleum wastes are eliminated from water and soil. The initial step in the microbial oxidation of alkanes is conversion of a terminal -CH3 group to a -CO2 group followed by p-oxidation,... 

Torres, E. Sandoval, J. V. Rosell, F. I., et al., Site-Directed Mutagenesis Improves the Biocatalytic Activity of Iso-l-Cytochrome-C in Polycyclic-Hydrocarbon Oxidation. Enzyme and Microbial Technology, 1995. 17(11) pp. 1014—1020. 

Tinoco, R., and VazquezDuhalt, R., Chemical Modification of Cytochrome C Improves Their Catalytic Properties in Oxidation of Polycyclic Aromatic Hydrocarbons. Enzyme and Microbial Technology, 1998. 22(1) pp. 8-12. 

Hambrick, G.A., Delaune, R.D., Patrick, W.H., Jr. (1980) Effects of estuarine sediment, pH and oxidation-reduction potential on microbial hydrocarbon degradation. Appl. Environ. Microbiol. 40, 365-9. 

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