Potential of indigenous biosurfactant-producing fungi from real crude oil sludge in total petroleum hydrocarbon degradation and its future research prospects

Abstract

In this study, biosurfactant-producing fungi isolated from crude oil sludge were tested to degrade total petroleum hydrocarbons (TPHs) in contaminated sludge. Polymerase chain reaction (PCR) was performed, and the phylogenetic tree based on the fungi genomic sequence was constructed using MEGA-X software and had identified the isolated fungi as Aspergillus terrus isolate Shu1 and Aspergillus fumigatus isolate Shu2 species. A. fumigatus isolate Shu2 showed a better potential of biosurfactant-producing fungi compared to A. terrus isolate Shu1, based on qualitative (parafilm, drop collapse, oil spreading, emulsion index) and quantitative (surface tension) analyses. Further TPH degradation by A. fumigatus isolate Shu2 was done under two conditions with the absence of additional nutrition and with additional nutrition for 45 days. Gas chromatography-flame ionisation detector (GC-FID) analysis showed TPH degradation by A. fumigatus of approximately 57 ± 2% in the first 16 days of treatment. The addition of nutrients inside the system had significantly increased (p < 0.05) the total removal of TPH up to 63 ± 2% (6% higher) within the 16 days. These findings suggest that A. fumigatus isolate Shu2 is a good potential as biosurfactant-producing fungi and is capable of degrading TPH from contaminated sludge. This study also verified that the TPH content of hydrocarbon-contaminated sludge was significantly reduced in the treatment with the presence of additional nutrient.