Biocatalytic transformation of petroporphyrins by chemical modified cytochrome C.
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.
Instituto de Biotecnología UNAM, Apartado Postal 510-3, Cuernavaca, Morelos, 62250 Mexico.
Humberto
H
García-Arellano
Eduardo
E
Buenrostro-Gonzalez
Rafael
R
Vazquez-Duhalt
D019943:Amino Acid Substitution; D000818:Animals; D001711:Biotransformation; D002384:Catalysis; D045304:Cytochromes c / Q000737:chemistry*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004951:Esterification; D006736:Horses; D009206:Myocardium / Q000378:metabolism; D010084:Oxidation-Reduction; D010578:Petroleum; D011092:Polyethylene Glycols / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*
D010578:Petroleum; D011166:Porphyrins; D011092:Polyethylene Glycols; D045304:Cytochromes c