Enhanced Degradation of Carcinogenic PAHs Benzo (a) Pyrene and Benzo (k) Fluoranthene by a Microbial Consortia

Abstract

Background/Objectives: Bioremediation of High Molecular Weight PAHs (HMW PAHs) with a combination of microorganisms was investigated. In the present study, the PAHs degradation capacity of a microbial consortium consisting of fungal, bacterial cultures was evaluated. Within 7 days, consortium showed 64% and 69% degradation of Benzo (a) pyrene (BaP) and Benzo (k) fluoranthene (BkF) each PAH of 30mg/L concentration respectively as the sole carbon source. The culture broth was analyzed for the presence of metabolites by gas Chromatography-Mass Spectrometry (GC-MS) and the activities of enzymes produced by the consortium were also assayed during the degradation process. Coexistence of three metabolic pathways, cytochrome P450 monooxygenase with the detection of epoxy derivatives leading to phenols, trans-dihydrodiols, cis-dihyrodiols leading to salycyclicacid and catechol by bacterial dioxygenases and via quinones of ligninolytic pathway were identified. Besides, Microbial consortia also demonstrated good biosurfactant production capacity, achieving a maximum emulsification activity of 61% (BaP and BkF) in the presence of PAHs as sole carbon source. These results indicate that this consortium can be used in the bioremediation of PAHs mixtures cometabolically in the contaminated environments.Keywords: Biosurfactant, Degradation Pathways, GC-MS Metabolites, PAHs, Microbial Consortium