Group of Molecular Microbial Ecology, Institute of Aquatic Ecology, University of Girona, Avda Montilivi s/n, Girona, Spain.
Chemosphere. 2011 Mar;83(2):104-16. doi: 10.1016/j.chemosphere.2011.01.016. Epub 2011 Feb 4.
To highlight the effects of a variety of chlorophenols (CP) in relation to the response of an indigenous bacterial community, an agricultural Mediterranean calcareous soil has been studied in microcosms incubated under controlled laboratory conditions. Soil samples were artificially polluted with 2-monochlorophenol (MCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP), at concentrations ranging from 0.1 up to 5000 mg kg(-1). Both activity and composition of the microbial community were assessed during several weeks, respectively, by respirometric methods and PCR-DGGE analysis of extracted DNA and RNA. Significant decreases in soil respirometric values and changes in the bacterial community composition were observed at concentrations above 1000 mg kg(-1) MCP and TCP, and above 100 mg kg(-1) PCP. However, the persistence of several active bacterial populations in soil microcosms contaminated with high concentration of CP, as indicated by DGGE fingerprints, suggested the capacity of these native bacteria to survive in the presence of the pollutants, even without a previous adaptation or contact with them. The isolation of potential CP degraders was attempted by culture plating from microcosms incubated with high CP concentrations. Twenty-three different isolates were screened for their resistance to TCP and PCP. The most resistant isolates were identified as Kocuria palustris, Lysobacter gummosus, Bacillus sp. and Pseudomonas putida, according to 16S rRNA gene homology. In addition, these four isolates also showed the capacity to reduce the concentration of TCP and PCP from 15% to 30% after 5d of incubation in laboratory assays (initial pollutant concentration of 50 mg L(-1)). Isolate ITP29, which could be a novel species of Bacillus, has been revealed as the first known member in this bacterial group with potential for CP bioremediation applications, usually wide-spread in the soil natural communities, which has not been reported to date as a CP degrader.
为了强调各种氯苯酚（CP）对土著细菌群落反应的影响，在控制实验室条件下的微宇宙中研究了农业地中海石灰质土壤。土壤样品用 2-氯苯酚（MCP）、2,4,6-三氯苯酚（TCP）和五氯苯酚（PCP）以 0.1 至 5000mgkg（-1）的浓度进行人工污染。在数周内分别通过呼吸测定法和提取 DNA 和 RNA 的 PCR-DGGE 分析评估微生物群落的活性和组成。在 MCP 和 TCP 浓度高于 1000mgkg（-1）和 PCP 浓度高于 100mgkg（-1）时，土壤呼吸值显著降低，并且细菌群落组成发生变化。然而，DGGE 指纹图谱表明，在高浓度 CP 污染的土壤微宇宙中，一些活跃的细菌种群仍然存在，这表明这些土著细菌即使在没有先前适应或接触污染物的情况下，也有能力在污染物存在的情况下存活。通过在高 CP 浓度下培养的微宇宙进行培养平板分离尝试分离潜在的 CP 降解菌。从对 TCP 和 PCP 具有抗性的 23 种不同分离物中筛选。根据 16S rRNA 基因同源性，最具抗性的分离物鉴定为粘质沙雷氏菌、粘质沙雷氏菌、芽孢杆菌和恶臭假单胞菌。此外，这四个分离物在实验室试验中（初始污染物浓度为 50mgL（-1））孵育 5d 后，还能够将 TCP 和 PCP 的浓度降低 15%至 30%。ITP29 分离物可能是芽孢杆菌的一个新种，它被揭示为该细菌组中第一个具有 CP 生物修复应用潜力的成员，通常广泛存在于土壤自然群落中，迄今为止尚未报道为 CP 降解菌。
