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Neosartorya fischeri, an Aspergillaceae fungus, was evaluated in its capacity to transform high molecular weight polycyclic aromatics hydrocarbons (HMW-PAHs) and the recalcitrant fraction of petroleum, the asphaltenes. N. fischeri was able to grow in these compounds as sole carbon source. Coronene, benzo(g,h,i)perylene, and indeno(1,2,3-c,d)pyrene, together with the asphaltenes, were assayed for fungal biotransformation. The transformation of the asphaltenes and HMW-PAHs was confirmed by reverse-phase high-performance liquid chromatography (HPLC), nano-LC mass spectrometry, and IR spectrometry. The formation of hydroxy and ketones groups on the PAH molecules suggest a biotransformation mediated by monooxygenases such as cytochrome P450 system (CYP). A comparative microarray with the complete genome from N. fischeri showed three CYP monooxygenases and one flavin monooxygenase genes upregulated. These findings, together with the internalization of aromatic substrates into fungal cells and the microsomal transformation of HMW-PAHs, strongly support the role of CYPs in the oxidation of these recalcitrant compounds.

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.

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Asphaltenes are considered as the most recalcitrant petroleum fraction and represent a big problem for the recovery, separation and processing of heavy oils and bitumens. Neosartorya fischeri is a saprophytic fungus that is able to grow using asphaltenes as the sole carbon source [1].We performed transcription profiling using a custom designed microarray with the complete genome from N. fischeri NRRL 181 in order to identify genes related to the transformation of asphaltenes [1]. Data analysis was performed using the genArise software. Results showed that 287 genes were up-regulated and 118 were down-regulated.Here we describe experimental procedures and methods about our dataset (NCBI GEO accession number GSE68146) and describe the data analysis to identify different expression levels in N. fischeri using this recalcitrant carbon source.