Bacteria and fungi mediated degradation of poly aromatic hydrocarbons and effect of surfactant Tween-80

Abstract

ABSTRACT Microorganisms (17 bacteria and 3 fungi) isolated from crude oil-contaminated soils were evaluated for degradation of five polyaromatic hydrocarbons (PAHs), both in the absence (-T80) and the presence of surfactant Tween-80 (+T80) at a 10 mg L−1 concentration of each PAH. Results of the heat map and Tukey HSD revealed that highest PAH degradation was observed by Kocuria rosea in +T80 treatment. Degradation (%) of individual PAH (-T80, +T80) was naphthalene: 96.6, 98.9; fluorene: 93.8, 95.1; phenanthrene: 58.1, 70.9; anthracene: 19.9, 32.5 and pyrene: 13.8, 54.7, respectively. Tukey HSD further revealed that all three fungi Trichoderma atroviride, Aspergillus nidulans and Aspergillus sydowii showed almost similar degradation of selected PAH. Based on degradation ability, consortia of K. rosea and A. sydowii were used for PAH degradation at 10, 50 and 100 mg L−1 in the presence of Tween-80. Results suggested that PAH degradation slowed down with the increase in the concentration. PAH degradation products phthalic acid and anthrone or phenanthrene-9,10 oxide or 9-phenanthrol were identified as a product of degradation. Bacterial strain Arthrobacter pascens, Pseudomonas aeruginosa, Bacillus megaterium, Bacillus sp., Bacillus niacini and Bacillus siamensis showed high fluorescence diacetate (FDA) hydrolase activity, whilst A. pascens, K. rosea, Pseudomonas sp. and B. niacini showed a significant soluble protein content.