| 14991657 |
Garcia-Arellano H, Buenrostro-Gonzalez E, Vazquez-Duhalt R: Biocatalytic transformation of petroporphyrins by chemical modified cytochrome C. Biotechnol Bioeng. 2004 Mar 30;85(7):790-8.
A semi-synthetic biocatalyst was prepared by a double chemical modification of cytochrome c. Free amino groups were modified with poly (ethylene glycol) while free carboxylic groups were alkylated to form methyl esters. The double chemically modified protein, PEG-Cyt-Met, oxidized synthetic porphyrins in a ternary solvent mixture composed by methylene chloride, methanol, and phosphate buffer. The highest activity was found in the ternary systems with low water content (5%). The use of relatively hydrophobic peroxides, such as tert-butyl and cumene hydroperoxides, extended the operational life of the biocatalyst, which, in turn, resulted in an extended oxidation of the substrates tested. PEG-Cyt-Met is able to transform asphaltenes, a highly recalcitrant petroleum fraction. The huge energetic resource found as asphaltene-rich deposits is the driving force to investigate and to innovate upgrading technologies, including biotechnological strategies. |
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