Biodegradation of Polyaromatic Hydrocarbons using Phellinus noxius BRB 11 Isolated from Berbak-Sembilang Biosphere Reserve, Indonesia

Abstract

Microbial biodegradation of Polyaromatic Hydrocarbons (PAHs) mixture is an eco-friendly practice that requires the exploration of efficient bio-degraders. In this study, three fungal species i.e., Phellinus noxius BRB 11, Leiotrametes menziesii BRB 73, and Ceriporia lacerata BRB 81, were screened out for phenanthrene (PHE) degradation. MnP and laccase of each fungus was analysed using microplate reader while PHE degradation was analysed by gas chromatography. The capability of the selected fungus was then performed in the following four single PAHs treatments i.e., PHE, anthracene (ANT), and Benzo (a)pyrene (BaP), and their mixtures i.e., PHE–ANT, PHE–BaP, ANT–BaP, ANT– PHE–BaP. PHE (100 ppm) final concentration was subjected to only crude laccase enzymes of the selected fungus, and with the addition of 1-Hydroxybenzotriazole (1-HBT), 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO), and Violuric acid (VA) as mediators. These mediators were used in 0.1, 0.3, 0.5, 1, 2, 3, and 4 mM concentration. Toxicity evaluation of degraded and non-degraded PAHs was performed using Vigna radiata and Artemia salina. The results showed that the enzymatic activity was high in BRB 11, and PHE biodegradation results from BRB 11, BRB 73 and BRB 81 i.e. 95%, 24%, and 26%, respectively. Further research was performed using the selected fungus, P. noxius BRB 11. In the single and mixture PAHs degradation experiment, all PAHs except for ANT was degraded above 90%. While BaP was degraded higher than its single degradation. During the degradation, ten metabolites were detected by GCMS and bio-detoxification was observed in all the treated samples. Among mediators used, TEMPO was the most efficient mediator with highest degradation rate on 0.1 mM until 2 mM concentration. PHE degradation was high at 0.1 mM of all mediator concentration, but starts decreasing as 1-HBT and VA mediators approached to higher concentrations. Laccase treated PAH was less toxic to Vigna radiata and Artemia salina than control. This study suggests that Phellinus noxius BRB 11 could be used as a potent PAHs degrader from the environment.