Characterization of Exiguobacterium Profundum Isolated From Petrochemical Waste (Bitumen) For Bioremediation and Bioelectricity Production Using Microbial Fuel Cell Technology

Abstract

The persistent contamination of soil and water by bitumen and other petrochemical wastes presents serious environmental and public health challenges, particularly in regions with natural hydrocarbon deposits such as Agbabu, Ondo State, Nigeria. This study aimed to isolate, characterize, and evaluate the bioremediation and bioelectricity generation potential of Exiguobacterium profundum recovered from bitumen-contaminated sediments. Standard microbiological techniques were employed for isolation, followed by biochemical characterization and molecular identification using 16S rRNA gene sequencing, which confirmed the presence of the isolate Exiguobacterium profundum (Accession No. PP278055). Biodegradation efficiency was assessed over a 30-day incubation period using gravimetric analysis and Gas Chromatography–Mass Spectrometry (GC-MS). The isolate achieved a 36.2% reduction in bitumen weight, with GC-MS results indicating transformation of complex hydrocarbons such as decane, hexadecane, and eicosane into simpler compounds including fatty acids (oleic acid, hexadecanoic acid, and octadecanoic acid), confirming active metabolic degradation pathways. Furthermore, the organism was evaluated in a constructed dual-chamber Microbial Fuel Cell (MFC) system using potassium permanganate as a mediator. The system generated an initial peak voltage of 1.11 V and current of 0.31 A, although outputs gradually declined over 14 days, likely due to substrate depletion and reduced microbial activity. The findings demonstrate that E. profundum possesses significant hydrocarbon-degrading and electrogenic capabilities, highlighting its dual applicability in sustainable bioremediation and bioelectricity production. This study establishes the potential of indigenous microbial resources as cost-effective and environmentally friendly tools for integrated petrochemical waste management and renewable energy recovery.