Earticle

초록

영어

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds composed of two or more fused aromatic rings that are important components of crude oil, creosote and coal tar. PAHs are the cause of great environmental concern because of their persistence, toxicity, mutagenicity, and carcinogenicity; they are on "priority-pollutant" lists in most countries. Bioremediation employing microorganisms that can degrade PAHs has proven to be a non-disruptive, cost-effective and highly efficient method of safely breaking down environmentally persistent compounds, including PAHs. Gaining an understanding of PAH-degrading bacteria, especially those occurring at contaminated sites, may result in clean-up strategies that can be effective in reducing PAH concentrations to below toxic levels. Sea-tidal flats are characterized by high primary production and nutrient cycling rates, which may rely upon high microbial abundance and diversity. We hypothesized that the Taean tidal flat sediments may also harbor diverse PAH-degrading microbial communities. The present study therefore aimed to investigate (i) the diversity and composition of the PAH-degrading bacterial populations enriched from the contaminated sea-tidal flat on the Taean coast; (ii) the isolation of PAH biodegrading bacteria from the enriched bacterial consortia and their PAH degradation abilities; and (iii) monitoring of the abundance of Alteromonas populations and in situ expression of Alteromonas-specific dioxygenase genes in the contaminated sea-tidal flat over time. Following the 2007 oil spill in South Korean tidal flats, we sought to identify microbial players influencing the environmental fate of released polycyclic aromatic hydrocarbons (PAHs). Two years of monitoring showed that PAH concentrations in sediments declined substantially. Enrichment cultures were established using seawater and modified minimal media containing naphthalene as sole carbon source. The enriched microbial community was characterized by 16S rRNA-based DGGE profiling; sequencing selected bands indicated Alteromonas (among others) were active. Alteromonas sp. SN2 was isolated and was able to degrade naphthalene, phenanthrene, anthracene, and pyrene in laboratory-incubated microcosm assays. PCR-based analysis of DNA extracted from the sediments revealed naphthalene dioxygenase (NDO) genes of only two bacterial groups: Alteromonas and Cycloclasticus, having gentisate and catechol metabolic pathways, respectively. However, reverse transcriptase PCR (RT-PCR)-based analysis of field-fixed mRNA revealed in situ expression of only the Alteromonas-associated NDO genes; in laboratory microcosms these NDO genes were markedly induced by naphthalene addition. Analysis by GC/MS showed that naphthalene in tidal- flat samples was metabolized predominantly via the gentisate pathway; this signature metabolite was detected (0.04 μ M) in contaminated field sediment. A qPCR-based two-year data set monitoring Alteromonas-specific 16S rRNA genes and NDO transcripts in sea-tidal flat field samples showed that the abundance of bacteria related to strain SN2 during the winter season was 20-fold higher than in the summer season. Based on the above data, we conclude that strain SN2 and its relatives are site natives-- key players in PAH degradation and adapted to winter conditions in these contaminated sea-tidal-flat sediments

저자

• Hyun Mi JIN [ School of Biological Sciences, Chung-Ang University, Seoul, 156-756, Republic of Korea. ]
• Che Ok JEON [ School of Biological Sciences, Chung-Ang University, Seoul, 156-756, Republic of Korea. ]

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  한국생물공학회 학술대회

• 간기

  반년간

• 수록기간

  1985~2013

• 십진분류

  KDC 476 DDC 576