Alkanes cytochrome P450 bacteria

The operation of cytochrome P450 in alkane oxidation has been reported both in bacteria and in yeasts. It has been shown that alkane hydroxylases of CHYP 153 are widespread both in Gram-negative and Gram-positive bacteria that lack the integral membrane alkane hydroxylase (van Beilin et al. 2006). 

Hydroxylases with properties similar to those of cytochrome P450 but containing nonheme iron catalyze co-oxidation of alkanes and fatty acids in certain bacteria, e.g., Pseudomonas oleovarans. A flavoprotein rubredoxin reductase, is also required.501 The methylotrophs Methylococcus and Methylosinus hydroxylate methane using as cosubstrate NADH or NADPH (Eq. 18-59). A soluble complex consists of 38-kDa reductase containing FAD and an Fe2S2... 

A group of related bacterial enzymes hydroxylate alkanes,507 toluene,508 phenol,509 and other substrates.5093 Eukaryotic fatty acid desaturases (Fig. 16-20B) belong to the same family.508 Some bacteria use cytochrome P450 or other oxygenase to add an oxygen atom to an alkene to form an epoxide. For example, propylene... 

Alkanes are abundant components of petroleum but normally react only under tbe most vigorous conditions (combustion free radicals sucb as Cl and HO). If tbeir C-H bonds could be activated under mild conditions, especially if this could be done catalytically, then it would be feasible to convert alkanes from mere fuel to fine chemicals that might be used and recycled. This is particularly desirable for methane (CH4), a by-product of anaerobic bacteria and a potential source of methanol (CH3OH). Nature routinely activates C-H bonds on saturated 4-coordinate carbon when enzymes called oxygenases employ cytochrome-P450 to catalyze conversions to alcohols ... 

Hydrocarbons, similarly to glucose, are oxidized to CO2 by propionibacteria (Fig. 3.8). Cetyl alcohol and palmitic acid, found in the incubation medium (Table 3.2), apparently serve as intermediates in the oxidation of hexadecane (Vorobjeva et al., 1979a). Some CO-binding proteins, known as cytochromes P450, are involved in the hydroxylation of alkanes. In this context, the finding of CO-binding pigments in four species of propionic acid bacteria (de Vries et al., 1972) should be noted. 

These bacteria also have epoxide hydrolase activity, and can form e.g. 9, 10-dihydroxy 18 0 from 9,10-epoxy 18 0. Many eubacteria have an 02-dependent monooxygenase (cytochrome P450) that can catalyze hydroxylation and epoxidation of fatty acids and hydrocarbons Ai-alkanes are metabolized to primary alcohols, fatty acids to co-OH compounds, and unsaturated hydrocarbons to epoxides (282). 

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