Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process

Abstract:

Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08mgmL−1) after 48h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology.

 

Vieira, Gabriela A.L., Magrini, Mariana Juventina, Bonugli-Santos, Rafaella C., Rodrigues, Marili V.N., Sette, Lara D. (2018).  Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process. Brazilian Journal of Microbiology xxx (2018) p xxx-xxx. dx.doi.org/10.1016/j.bjm.2018.04.007.

 

In this article, the researchers investigate the potential of 3 basidiomycete fungal strains isolated from ocean sponges in Brazil to degrade high molecular weight PAHs. One of the three fungal strains showed a much higher potential to degrade pyrene and Benzo(a)pyrene (BaP), so the researchers designed a series of experiments to determine several optimum environmental conditions for the fungal strain to degrade pyrene and BaP. The researchers also tested toxicity of the degradation products using shrimp larvae, and saw a significant decrease in toxicity from a solution of only pyrene, to a solution of pyrene and the degrading fungal strain. The study provides an important look at a fungal strain with enormous potential to degrade toxic PAHs pollution in the environment.

This article interests me because fungi aren’t often the focus of microbiological research, let alone marine fungi. While the paper hasn’t yet been published in print and is so far only available online, I’m interested in seeing if this paper will influence commercial bioaugmentation products in the future.

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