Microbial and Enzymatic Biotransformations of Asphaltenes

Asphaltenes are considered the most recalcitrant fraction of oils. Nevertheless, there are reports with rigorous experimental procedures that clearly demonstrate the capacity of enzymes and few microorganisms to transform asphaltenes. These microorganisms, fungi and bacteria, may contain a unique or very versatile enzymatic system that allows the transformation and mineralization of the highly complex asphaltene molecules. For enzymatic reactions, the biotransformation may occur only when the asphaltenes and the enzyme are in the same phase, reducing the mass transfer limitations. In this work, literature on the biotransformations of asphaltene fraction is critically reviewed.