Biodegradation of heavy oil by fungal extracellular enzymes fromAspergillusspp. shows potential to enhance oil recovery

Abstract

AbstractMicrobial enhanced oil recovery makes a substantial contribution to the recovery of heavy oils; however, most methods use bacteria, with less attention paid to the potential of fungi. In this study, we investigated the efficiency of fungal extracellular enzymes in biotransformation of heavy oil fractions into light compounds. TwoAspergillusisolates (A. terreusandA. nidulans) with the ability to biodegrade heavy oil were isolated from bitumen. The extracellular enzymes from theseAspergillusisolates exhibited dehydrogenase and catechol 2,3‐dioxygenase activities. The biodegradation of heavy oil was coupled with abundant production of gases, mainly CO2and H2. Gas chromatography analysis revealed a redistribution ofn‐alkanes in heavy oil after treatment with crude enzyme extracts, which resulted in an increase in individualn‐alkanes. The viscosity of heavy oil was decreased considerably by enzymatic degradation. These results demonstrate the potential of fungal extracellular enzymes fromAspergillusspp. for applications in enhanced heavy oil recovery.