Biotransformation of petroleum asphaltenes and high molecular weight polycyclic aromatic hydrocarbons by Neosartorya fischeri

Abstract

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.

Responses of Microbial Communities to Hydrocarbon Exposures

“…The underlying mechanism and genetic pathways involved are not yet known. The fungus N. fischeri also grows on asphaltenes as a sole carbon source (Hernández-López et al, 2016), possibly using cytochrome P450 monooxygenases to process asphaltenes. Other fungal isolates degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) using cytochrome P450s (Syed et al, 2011).…”

Biodegradation of asphaltene and petroleum compounds by a highly potent Daedaleopsis sp.

“…Biodegradation of petroleum hydrocarbons by bacteria, fungi, and yeasts is regarded as the main mechanism of eliminating hydrocarbon pollutants from the environment . Very few microorganisms have been reported to biodegrade asphaltenes as the most recalcitrant crude oil fraction . The reports included biodegradation or mineralization of asphaletes by mixed bacteria and recently by Neosartorya fischeri , and Pestalotiopsis sp.…”

“…Very few microorganisms have been reported to biodegrade asphaltenes as the most recalcitrant crude oil fraction . The reports included biodegradation or mineralization of asphaletes by mixed bacteria and recently by Neosartorya fischeri , and Pestalotiopsis sp. .…”

Bioremediation of soils contaminated with petroleum solid wastes and drill cuttings by Pleurotus sp. under different treatment scales

“…6%. There is very little evidence of fungi that can degrade asphalts and resins; to date, some examples have been described in detail e.g., the ascomycetes Neosartorya fischeri (15.5% asphaltene biodegradation in several weeks) [21], Pestalotiopsis sp. (77% in 30 days) [22] and recently the basidiomycete Daedaleopsis sp.…”

“…5), suggests a plausibly strategy to degrade aliphatic hydrocarbons, and could explain the high efficiency in the degradation of saturated fractions reported in this study. It's worth mentioning a coding sequence for aryl 4-monooxygenase (EC 1.14.14.1), member of the cytochrome P450 system, enzyme related with the oxidation of polycyclic aromatics hydrocarbons [21]. These observations suggest that Pleurotus possesses a metabolic potential that allows it to fill niches related to the degradation of petroleum hydrocarbons.…”