Size Exclusion Chromatography Protein Profile of Selenastrum capricornutum Culture Extracts Degrading Benzo( a )Pyrene

Benzo[a]pyrene (B[a]P) is an environmentally ubiquitous, persistent, and carcinogenic pollutant belonging to the polycyclic aromatic hydrocarbons (PAHs) family. Several methods have been employed to follow PAH degradation by bacteria. However, there is very scarce information about microalgae as bioremediation species. In this work, we investigated the protein profile for B[a]P degradation by the Selenastrum capricornutum algae culture extract employing high-performance liquid chromatography (HPLC) in size exclusion chromatography mode (SEC) and electrophoresis (sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE]). We evaluated the degradation of crude extracts (CEs) and SEC fractions, and we found the presence of trace levels of 4, 5-dihydrodiolbenzo[a]pyrene (4,5-dB[a]P) and 7,8-dihydrodiolbenzo[a]pyrene (7,8-dB[a]P) in cis geometry as B[a]P degradation products. SEC chromatographic profile comparison of CEs and SEC fractions, both exposed to B[a]P along with the corresponding controls, allowed us the identification of molecular weights (MWs) of a multi-component system involved in the B[a]P biodegradation through protein over-production. Electrophoresis analysis showed several protein components, with MWs between 10 and 250 kDa, where two subunits of 38.15–41.97 and 82.73 ± 3.15 kDa suggested the presence of multi-component di-oxygenases in the early stages of B[a]P biodegradation by S. capricornutum cultures. This work extends the knowledge of the biodegradation process of high molecular PAHs by microalgae.