Fungal laccases have high catalytic efficiency and are utilized for the removal of crude oil because they oxidize various aliphatic and aromatic hydrocarbons and convert them into harmless compounds or less toxic compounds, thus accelerating the biodegradation potential of crude oil. Laccases are important gene families and the function of laccases genes varied widely based on transcription and function. Biodegradation of crude oil using Aspergillus terreus KC462061 was studied in the current study beside the transcription level of eight laccase (Lcc) genes have participated in biodegradation in the presence of aromatic compounds, and metal ions. Time-course profiles of laccase activity in the presence of crude oil indicated that the five inducers individual or combined have a very positive on laccase activity. In the status of the existence of crude oil, the synergistic effect of Cu-ABTS compound caused an increase in laccase yields up to 22-fold after 10 days than control. The biodegradation efficiencies of A. terreus KC462061 for aliphatic and aromatic hydrocarbons of crude oil were 82.1 ± 0.2% and 77.4 ± 0.6%, respectively. The crude oil biodegradation efficiency was improved by the supplemented Cu-ABTS compound in A. terreus KC462061. Gas chromatography-mass spectrometry was a very accurate tool to demonstrate the biodegradation efficiencies of A. terreus KC462061 for crude oil. Significant differences were observed in the SDS-PAGE of A. terreus KC462061 band intensities of laccase proteins after the addition of five inducers, but the Cu-ABTS compound highly affects very particular laccase electrophoresis. Quantitative real-time polymerase chain reaction (qPCR) was used for the analysis of transcription profile of eight laccase genes in A. terreus KC462061 with a verified reference gene. Cu2+ ions and Cu-ABTS were highly effective for efficient laccase expression profiling, mainly via Lcc11 and 12 transcription induction. The current study will explain the theoretical foundation for laccase transcription in A. terreus KC462061, paving the road for commercialization and usage.
Keywords: Aspergillus terreus KC462061; biodegradation; differential regulation; laccase; promoter; qPCR.