Degradation of long-chain alkanes by a polyethylene-degrading fungus, Penicillium simplicissimum YK

Abstract

This study investigated the removal of long-chain alkanes, which are released as the result of shipping activities and fuel oil spills, with Penicillium simplicissimum YK, a fungus that degrades polyethylene. Two branched alkanes (pristane and squalane) and a phosphoric ester (Plysurf A210G) were used separately as a dispersant. Yeast extract and malt extract were added as a supplementary nutrient, respectively, to enhance cell growth. Squalane was found to be more favorable to the long-chain n-alkane degradation than pristine when the cell density was higher. When 0.001% (w/v) Plysurf A210G was used as the dispersant and 0.3% malt extract was added as the supplementary nutrient, about 26% to 51% of an initial concentration of 0.10% (w/v) of n-alkanes 30 to 40 carbons long was degraded in two weeks. In this case, no apparent correlation was observed between the molecular weights of the long-chain n-alkanes and their degradation rates. In a separate experiment, it was confirmed that the fungus used pristane, squalane, and n-alkanes with a chain of 20 and 50 carbons long for growth. This report demonstrated the biodegradability of the long-chain straight and branched alkanes by Penicillium simplicissimum YK.