title: Biodegradation of high concentrations of mixed polycyclic aromatic hydrocarbons by indigenous bacteria from a river sediment: a microcosm study and bacterial community analysis.
abstract: This study assessed the biodegradation of mixtures of polycyclic aromatic hydrocarbons (PAHs) by indigenous bacteria in river sediment. Microcosms were constructed from sediment from the Chao Phraya River (the main river in Thailand) by supplementation with high concentrations of fluorene, phenanthrene, pyrene (300 mg kg-1of each PAH), and acenaphthene (600 mg kg-1). Fluorene and phenanthrene were completely degraded, whereas 50% of the pyrene and acenaphthene were removed at the end of the incubation period (70 days). Community analyses revealed the dynamics of the bacterial profiles in the PAH-degrading microcosms after PAH exposure. Actinobacteria predominated and became significantly more abundant in the microcosms after 14 days of incubation at room temperature under aerobic conditions. Furthermore, the remaining PAHs and alpha diversity were positively correlated. The sequencing of clone libraries of the PAH-RHDα genes also revealed that the dioxygenase genes of Mycobacterium sp. comprised 100% of the PAH-RHDα library at the end of the microcosm setup. Moreover, two PAH-degrading Actinobacteria (Arthrobacter sp. and Rhodococcus ruber) were isolated from the original sediment sample and showed high activity in the degradation of phenanthrene and fluorene in liquid cultivation. This study reveals that indigenous bacteria had the ability to degrade high concentrations of mixed PAHs and provide clear evidence that Actinobacteria may be potential candidates to play a major role in PAH degradation in the river sediment.
authors.affiliation: Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Chanokporn
authors.initials: C
authors.lastname: Muangchinda
authors.affiliation: Biological Resource Center, National Institute of Technology and Evaluation, 2-49-10 Nishihara, Shibuya-ku, Tokyo, 151-0066, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamazoe
authors.affiliation: Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand.
authors.forename: Duangporn
authors.initials: D
authors.lastname: Polrit
authors.affiliation: Enzyme Technology Laboratory, National Center for Genetic Engineering and Biotechnology, Pathum Thani, 12120, Thailand.
authors.forename: Honglada
authors.initials: H
authors.lastname: Thoetkiattikul
authors.affiliation: Enzyme Technology Laboratory, National Center for Genetic Engineering and Biotechnology, Pathum Thani, 12120, Thailand.
authors.forename: Wuttichai
authors.initials: W
authors.lastname: Mhuantong
authors.affiliation: Enzyme Technology Laboratory, National Center for Genetic Engineering and Biotechnology, Pathum Thani, 12120, Thailand.
authors.forename: Verawat
authors.initials: V
authors.lastname: Champreda
authors.affiliation: Bioremediation Research Unit, Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand. onruthai@gmail.com.|Center of Excellence on Hazardous Substance Management (HSM), Bangkok, 10330, Thailand. onruthai@gmail.com.|Omics Sciences and Bioinformatics Center, Faculty of Science, Chulalongkorn University, Bangkok, 10330, Thailand. onruthai@gmail.com.
authors.forename: Onruthai
authors.initials: O
authors.lastname: Pinyakong
mesh_terms: D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000382:microbiology*; D011084:Polycyclic Aromatic Hydrocarbons / Q000378:metabolism*; D045483:Rivers; D013785:Thailand
chemical_list: D011084:Polycyclic Aromatic Hydrocarbons
keywords: Actinobacteria; Biodegradation; Dioxygenase; Polycyclic aromatic hydrocarbons; River sediment