Lab-scale bioremediation technology: Ex-situ bio-removal and biodegradation of waste cooking oil by Aspergillus flavus USM-AR1

Abstract Large amounts of waste cooking oil from residential areas can cause adverse effect on the environment if not disposed properly. Fungi have a higher tolerance to hydrocarbon toxicity due to their physiology and adaptation to the environment. Consequently, they can be employed in bioremediation to reduce waste oils release to the environment. This work aims to bio-remove and biodegrade the waste cooking oil using a newly isolated strain Aspergillus flavus USM-AR1, in stirred tank reactor (STR). The strain showed remarkable removal activity of waste cooking oil. The removal efficiency of waste cooking oil reached 97% on day 3 of cultivation. This was attained when the culture was agitated at 400 rpm, maintaining the Reynold’s number of that obtained in the shake flask culture. Fortuitously, the best dispersion of waste cooking oil was also obtained at 400 rpm. The highest cell surface hydrophobicity (MATH) at 76.42% was observed at day 3 of cultivation. The maximum biosurfactant and emulsification activity occurred at day 2 of cultivation, which were 43 mm and 44%, respectively. Cell surface hydrophobicity and biosurfactant produced by strain Aspergillus flavus USM-AR1 played an important role in bio-removal of waste cooking oil, making this strain a prospective candidate for treating waste cooking oil.