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Wang L, Zhang H, Xu C, Yuan J, Xu X, Wang J, Zhang Y. Long-term nitrogen fertilization and sweetpotato cultivation in the wheat-sweetpotato rotation system decrease alkaline phosphomonoesterase activity by regulating soil phoD-harboring bacteria communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 900:165916. [PMID: 37524185 DOI: 10.1016/j.scitotenv.2023.165916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 07/27/2023] [Accepted: 07/28/2023] [Indexed: 08/02/2023]
Abstract
The alkaline phosphomonoesterase (ALP)-harboring community (phoD-harboring community) plays a crucial role in the conversion of organic phosphorus (P) into available P (AP). However, the response mechanisms of phoD-harboring communities to fertilization strategies, crop types, and their interactions within the wheat-sweetpotato rotation are poorly understood. A nine-year field experiment of different fertilization strategies was established under the wheat-sweetpotato rotation. After harvesting the crop, we collected soil samples without fertilization (CK), inorganic NK fertilization (NK), inorganic NPK fertilization (NPK), and a combined application of inorganic NPK and organic fertilizer (NPKM). We employed high-throughput sequencing and enzymology techniques to analyze the composition and functional activity of phoD-harboring bacterial communities as well as their correlation with soil physicochemical properties. The results showed that long-term nitrogen (N) fertilization, especially inorganic N, significantly reduced soil pH and ALP activity while increasing AP compared with CK. The AP content in sweetpotato season was significantly higher than that in wheat season. Inorganic N fertilization dramatically reshaped the communities of phoD-harboring bacteria and decreased diversity. The phoD-harboring bacterial communities in sweetpotato season were significantly different from those in wheat season. The N fertilization significantly reduced the relative abundance of Acuticoccus, Methylibium, Rhizobacter, and Roseivivax, which was positively correlated with ALP activity. These groups in sweetpotato season decreased significantly compared with wheat season. A structural equation model indicates that pH and AP play a significant role in regulating the phoD-harboring bacteria communities, ALP activity, and their interactions. We demonstrate that fertilization strategies and crop types have a substantial impact on the phoD-harboring bacteria communities and functions, which are closely linked to soil pH and AP levels. Our study highlights the detrimental effects of soil acidification resulting from inorganic N fertilization on P-cycling bacterial communities and functions. However, the combination of inorganic and organic fertilizer can mitigate these adverse effects.
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Affiliation(s)
- Lei Wang
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Hui Zhang
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu University, Zhenjiang 212023, China
| | - Cong Xu
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu University, Zhenjiang 212023, China
| | - Jie Yuan
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Xianjü Xu
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
| | - Jidong Wang
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu University, Zhenjiang 212023, China.
| | - Yongchun Zhang
- National Agricultural Experimental Station for Agricultural Environment, Luhe, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu University, Zhenjiang 212023, China.
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2
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Huizenga JM, Semprini L. Influence of growth substrate and contaminant mixtures on the degradation of BTEX and MTBE by Rhodococcus rhodochrous ATCC strain 21198. Biodegradation 2023; 34:461-475. [PMID: 37329399 PMCID: PMC10803100 DOI: 10.1007/s10532-023-10037-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 05/30/2023] [Indexed: 06/19/2023]
Abstract
The degradation of the prevalent environmental contaminants benzene, toluene, ethylbenzene, and xylenes (BTEX) along with a common co-contaminant methyl tert-butyl ether (MTBE) by Rhodococcus rhodochrous ATCC Strain 21198 was investigated. The ability of 21198 to degrade these contaminants individually and in mixtures was evaluated with resting cells grown on isobutane, 1-butanol, and 2-butanol. Growth of 21198 in the presence of BTEX and MTBE was also studied to determine the growth substrate that best supports simultaneous microbial growth and contaminants degradation. Cells grown on isobutane, 1-butanol, and 2-butanol were all capable of degrading the contaminants, with isobutane grown cells exhibiting the most rapid degradation rates and 1-butanol grown cells exhibiting the slowest. However, in conditions where BTEX and MTBE were present during microbial growth, 1-butanol was determined to be an effective substrate for supporting concurrent growth and contaminant degradation. Contaminant degradation was found to be a combination of metabolic and cometabolic processes. Evidence for growth of 21198 on benzene and toluene is presented along with a possible transformation pathway. MTBE was cometabolically transformed to tertiary butyl alcohol, which was also observed to be transformed by 21198. This work demonstrates the possible utility of primary and secondary alcohols to support biodegradation of monoaromatic hydrocarbons and MTBE. Furthermore, the utility of 21198 for bioremediation applications has been expanded to include BTEX and MTBE.
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Affiliation(s)
- Juliana M Huizenga
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, Corvallis, OR, 97331, USA
| | - Lewis Semprini
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, 105 SW 26th St, Corvallis, OR, 97331, USA.
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3
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Liang Y, Li M, Pan F, Ma J, Yang Z, Ling T, Qin J, Lu S, Zhong F, Song Z. Alkaline Phosphomonoesterase-Harboring Microorganisms Mediate Soil Phosphorus Transformation With Stand Age in Chinese Pinus massoniana Plantations. Front Microbiol 2020; 11:571209. [PMID: 33329428 PMCID: PMC7728850 DOI: 10.3389/fmicb.2020.571209] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 11/04/2020] [Indexed: 12/05/2022] Open
Abstract
phoD-harboring microorganisms facilitate mineralization of organic phosphorus (P), while their role in the regulation of soil P turnover under P-limited conditions in Pinus massoniana plantations is poorly understood. The aim of the present study was to investigate the effects of stand age and season on soil P fractions and phoD-harboring microorganism communities in a chronosequence of Chinese P. massoniana plantations including 3, 19, and 58 years. The soil P fractions (i.e., CaCl2-P, citrate-P, enzyme-P, and HCl-P) varied seasonally, with the higher values observed in the rainy season. The concentrations of the fractions were higher in old plantation (OP) soils and lower in young planation (YP) soils in both seasons. The OTU abundances were negatively correlated with total available P concentration, while were positively correlated with alkaline phosphomonoesterase (ALP) activity at 0–10 cm soil depth. The results indicate that phoD-harboring microorganisms have great potential to mineralize organic P under P-poor conditions and highlights those microorganisms are indicators of P bioavailability in P. massoniana plantations.
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Affiliation(s)
- Yueming Liang
- Key Laboratory of Karst Dynamics, Ministry of Natural and Resources & Guangxi Zhuangzu Autonomy Region, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, China.,Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, China
| | - Mingjin Li
- Production and Operation Department, Zhenlong Forest Farm of Hengxian County, Nanning, China
| | - Fujing Pan
- College of Environmental and Engineering, Guangxi Key Laboratory of Theory and Technology for Environmental Pollution Control, Guilin University of Technology, Guilin, China
| | - Jiangming Ma
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, China
| | - Zhangqi Yang
- Engineering Research Center of Masson Pine of Guangxi, Guangxi Forestry Research Institute, Nanning, China
| | - Tianwang Ling
- Production and Operation Department, Zhenlong Forest Farm of Hengxian County, Nanning, China
| | - Jiashuang Qin
- Guangxi Institute of Botany, Chinese Academy of Sciences, Guilin, China
| | - Shaohao Lu
- Production and Operation Department, Zhenlong Forest Farm of Hengxian County, Nanning, China
| | - Fengyue Zhong
- Production and Operation Department, Zhenlong Forest Farm of Hengxian County, Nanning, China
| | - Zunrong Song
- Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin, China
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4
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Suk WA, Heacock ML, Trottier BA, Amolegbe SM, Avakian MD, Henry HF, Carlin DJ, Reed LG. Assessing the Economic and Societal Benefits of SRP-Funded Research. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:065002. [PMID: 29916809 PMCID: PMC6108577 DOI: 10.1289/ehp3534] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/17/2018] [Accepted: 04/24/2018] [Indexed: 05/30/2023]
Abstract
BACKGROUND The National Institute of Environmental Health Sciences (NIEHS) Superfund Basic Research and Training Program (SRP) funds a wide range of transdisciplinary research projects spanning the biomedical and environmental sciences and engineering, supporting and promoting the application of that research to solving real-world problems. OBJECTIVES We used a case study approach to identify the economic and societal benefits of SRP-funded research, focusing on the use of potentially hazardous substance remediation and site monitoring tools. We also identified successes and challenges involved in translating SRP grantees' research findings and advances into application. DISCUSSION We identified remediation and detection research projects supported by the SRP with the most potential for economic and societal benefits and selected 36 for analysis. To examine the benefits of these applied technologies, we interviewed 28 SRP-supported researchers and 41 partners. Five case studies emerged with the most complete information on cost savings-total savings estimated at >$100 million. Our analysis identified added societal benefits such as creation of small businesses, land and water reuse, sustainable technologies, exposure reduction, and university-industry partnerships. CONCLUSIONS Research funded by the SRP has yielded significant cost savings while providing additional societal benefits. https://doi.org/10.1289/EHP3534.
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Affiliation(s)
- William A Suk
- Superfund Research Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
| | - Michelle L Heacock
- Superfund Research Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
| | - Brittany A Trottier
- Superfund Research Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
| | | | | | - Heather F Henry
- Superfund Research Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
| | - Danielle J Carlin
- Superfund Research Program, National Institute of Environmental Health Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
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5
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Joshi G, Schmidt R, Scow KM, Denison MS, Hristova KR. Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1. MICROBIOLOGY-SGM 2016; 162:1563-1571. [PMID: 27450417 DOI: 10.1099/mic.0.000338] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds' impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1.
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Affiliation(s)
- Geetika Joshi
- Department of Land, Air and Water Resources, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Radomir Schmidt
- Department of Land, Air and Water Resources, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Kate M Scow
- Department of Land, Air and Water Resources, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Michael S Denison
- Department of Environmental Toxicology, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Krassimira R Hristova
- Department of Biological Sciences, Marquette University, Milwaukee, WI 53201, USA.,Department of Land, Air and Water Resources, One Shields Avenue, University of California, Davis, CA 95616, USA
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Sun W, Li Y, McGuinness LR, Luo S, Huang W, Kerkhof LJ, Mack EE, Häggblom MM, Fennell DE. Identification of Anaerobic Aniline-Degrading Bacteria at a Contaminated Industrial Site. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:11079-11088. [PMID: 26280684 DOI: 10.1021/acs.est.5b02166] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Anaerobic aniline biodegradation was investigated under different electron-accepting conditions using contaminated canal and groundwater aquifer sediments from an industrial site. Aniline loss was observed in nitrate- and sulfate-amended microcosms and in microcosms established to promote methanogenic conditions. Lag times of 37 days (sulfate amended) to more than 100 days (methanogenic) were observed prior to activity. Time-series DNA-stable isotope probing (SIP) was used to identify bacteria that incorporated (13)C-labeled aniline in the microcosms established to promote methanogenic conditions. In microcosms from heavily contaminated aquifer sediments, a phylotype with 92.7% sequence similarity to Ignavibacterium album was identified as a dominant aniline degrader as indicated by incorporation of (13)C-aniline into its DNA. In microcosms from contaminated canal sediments, a bacterial phylotype within the family Anaerolineaceae, but without a match to any known genus, demonstrated the assimilation of (13)C-aniline. Acidovorax spp. were also identified as putative aniline degraders in both of these two treatments, indicating that these species were present and active in both the canal and aquifer sediments. There were multiple bacterial phylotypes associated with anaerobic degradation of aniline at this complex industrial site, which suggests that anaerobic transformation of aniline is an important process at the site. Furthermore, the aniline degrading phylotypes identified in the current study are not related to any known aniline-degrading bacteria. The identification of novel putative aniline degraders expands current knowledge regarding the potential fate of aniline under anaerobic conditions.
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Affiliation(s)
- Weimin Sun
- Department of Environmental Sciences, Rutgers University , 14 College Farm Road, New Brunswick, New Jersey 08901, United States
| | - Yun Li
- Department of Environmental Sciences, Rutgers University , 14 College Farm Road, New Brunswick, New Jersey 08901, United States
| | | | - Shuai Luo
- Department of Environmental Sciences, Rutgers University , 14 College Farm Road, New Brunswick, New Jersey 08901, United States
| | - Weilin Huang
- Department of Environmental Sciences, Rutgers University , 14 College Farm Road, New Brunswick, New Jersey 08901, United States
| | | | - E Erin Mack
- DuPont, Corporate Remediation Group, Wilmington, Delaware 19714, United States
| | | | - Donna E Fennell
- Department of Environmental Sciences, Rutgers University , 14 College Farm Road, New Brunswick, New Jersey 08901, United States
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7
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Szabó Z, Gyula P, Robotka H, Bató E, Gálik B, Pach P, Pekker P, Papp I, Bihari Z. Draft genome sequence of Methylibium sp. strain T29, a novel fuel oxygenate-degrading bacterial isolate from Hungary. Stand Genomic Sci 2015. [PMID: 26221420 PMCID: PMC4517660 DOI: 10.1186/s40793-015-0023-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Methylibium sp. strain T29 was isolated from a gasoline-contaminated aquifer and proved to have excellent capabilities in degrading some common fuel oxygenates like methyl tert-butyl ether, tert-amyl methyl ether and tert-butyl alcohol along with other organic compounds. Here, we report the draft genome sequence of M. sp. strain T29 together with the description of the genome properties and its annotation. The draft genome consists of 608 contigs with a total size of 4,449,424 bp and an average coverage of 150×. The genome exhibits an average G + C content of 68.7 %, and contains 4754 protein coding and 52 RNA genes, including 48 tRNA genes. 71 % of the protein coding genes could be assigned to COG (Clusters of Orthologous Groups) categories. A formerly unknown circular plasmid designated as pT29A was isolated and sequenced separately and found to be 86,856 bp long.
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Affiliation(s)
- Zsolt Szabó
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Péter Gyula
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Hermina Robotka
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Emese Bató
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Bence Gálik
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Péter Pach
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Péter Pekker
- Materials Science Research Group, Hungarian Academy of Sciences-University of Miskolc, Miskolc, Hungary
| | - Ildikó Papp
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
| | - Zoltán Bihari
- Bay Zoltán Nonprofit Ltd. for Applied Research, Budapest, Hungary
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Joshi G, Schmidt R, Scow KM, Denison MS, Hristova KR. Gene mdpC plays a regulatory role in the methyl-tert-butyl ether degradation pathway of Methylibium petroleiphilum strain PM1. FEMS Microbiol Lett 2015; 362:fnv029. [PMID: 25724531 DOI: 10.1093/femsle/fnv029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Among the few bacteria known to utilize methyl tert-butyl ether (MTBE) as a sole carbon source, Methylibium petroleiphilum PM1 is a well-characterized organism with a sequenced genome; however, knowledge of the genetic regulation of its MTBE degradation pathway is limited. We investigated the role of a putative transcriptional activator gene, mdpC, in the induction of MTBE-degradation genes mdpA (encoding MTBE monooxygenase) and mdpJ (encoding tert-butyl alcohol hydroxylase) of strain PM1 in a gene-knockout mutant mdpC(-). We also utilized quantitative reverse transcriptase PCR assays targeting genes mdpA, mdpJ and mdpC to determine the effects of the mutation on transcription of these genes. Our results indicate that gene mdpC is involved in the induction of both mdpA and mdpJ in response to MTBE and tert-butyl alcohol (TBA) exposure in PM1. An additional independent mechanism may be involved in the induction of mdpJ in the presence of TBA.
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Affiliation(s)
- Geetika Joshi
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Radomir Schmidt
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Kate M Scow
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Michael S Denison
- Department of Environmental Toxicology, University of California, Davis, CA 95616, USA
| | - Krassimira R Hristova
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA Biological Sciences Department, Marquette University, Milwaukee, WI 53201, USA
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9
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Hicks KA, Schmidt R, Nickelsen MG, Boyle SL, Baker JM, Tornatore PM, Hristova KR, Scow KM. Successful treatment of an MTBE-impacted aquifer using a bioreactor self-colonized by native aquifer bacteria. Biodegradation 2013; 25:41-53. [PMID: 23613160 DOI: 10.1007/s10532-013-9639-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/06/2013] [Indexed: 11/26/2022]
Abstract
A field-scale fixed bed bioreactor was used to successfully treat an MTBE-contaminated aquifer in North Hollywood, CA without requiring inoculation with introduced bacteria. Native bacteria from the MTBE-impacted aquifer rapidly colonized the bioreactor, entering the bioreactor in the contaminated groundwater pumped from the site, and biodegraded MTBE with greater than 99 % removal efficiency. DNA sequencing of the 16S rRNA gene identified MTBE-degrading bacteria Methylibium petroleiphilum in the bioreactor. Quantitative PCR showed M. petroleiphilum enriched by three orders of magnitude in the bioreactor above densities pre-existing in the groundwater. Because treatment was carried out by indigenous rather than introduced organisms, regulatory approval was obtained for implementation of a full-scale bioreactor to continue treatment of the aquifer. In addition, after confirmation of MTBE removal in the bioreactor to below maximum contaminant limit levels (MCL; MTBE = 5 μg L(-1)), treated water was approved for reinjection back into the aquifer rather than requiring discharge to a water treatment system. This is the first treatment system in California to be approved for reinjection of biologically treated effluent into a drinking water aquifer. This study demonstrated the potential for using native microbial communities already present in the aquifer as an inoculum for ex-situ bioreactors, circumventing the need to establish non-native, non-acclimated and potentially costly inoculants. Understanding and harnessing the metabolic potential of native organisms circumvents some of the issues associated with introducing non-native organisms into drinking water aquifers, and can provide a low-cost and efficient remediation technology that can streamline future bioremediation approval processes.
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Affiliation(s)
- Kristin A Hicks
- Department of Land, Air and Water Resources, University of California, One Shields Ave, Davis, CA, 95616, USA
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North KP, Mackay DM, Annable MD, Sublette KL, Davis G, Holland RB, Petersen D, Scow KM. An ex situ evaluation of TBA- and MTBE-baited bio-traps. WATER RESEARCH 2012; 46:3879-3888. [PMID: 22621895 PMCID: PMC3582699 DOI: 10.1016/j.watres.2012.04.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 04/13/2012] [Accepted: 04/19/2012] [Indexed: 06/01/2023]
Abstract
Aquifer microbial communities can be investigated using Bio-traps(®) ("bio-traps"), passive samplers containing Bio-Sep(®) beads ("bio-beads") that are deployed in monitoring wells to be colonized by bacteria delivered via groundwater flow through the well. When bio-beads are "baited" with organic contaminants enriched in (13)C, stable isotope probing allows assessment of the composition and activity of the microbial community. This study used an ex situ system fed by groundwater continuously extracted from an adjacent monitoring well within an experimentally-created aerobic zone treating a tert-butyl alcohol (TBA) plume. The goal was to evaluate aspects of bio-trap performance that cannot be studied quantitatively in situ. The measured groundwater flow through a bio-trap housing suggests that such traps might typically "sample" about 1.8 L per month. The desorption of TBA or methyl tert-butyl ether (MTBE) bait from bio-traps during a typical deployment duration of 6 weeks was approximately 90% and 45%, respectively, of the total initial bait load, with initially high rate of mass loss that decreased markedly after a few days. The concentration of TBA in groundwater flowing by the TBA-baited bio-beads was estimated to be as high as 3400 mg/L during the first few days, which would be expected to inhibit growth of TBA-degrading microbes. Initial inhibition was also implied for the MTBE-baited bio-trap, but at lower concentrations and for a shorter time. After a few days, concentrations in groundwater flowing through the bio-traps dropped below inhibitory concentrations but remained 4-5 orders of magnitude higher than TBA or MTBE concentrations within the aquifer at the experimental site. Desorption from the bio-beads during ex situ deployment occurred at first as predicted by prior sorption analyses of bio-beads but with apparent hysteresis thereafter, possibly due to mass transfer limitations caused by colonizing microbes. These results suggest that TBA- or MTBE-baited bio-traps could be baited at lower initial total mass loading with no detriment to trapping ability. The bio-traps were able to collect detectable amounts of microbial DNA and thus allow some insight into the sparse microbial community present in the aquifer during remediation of the low concentration plume.
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Affiliation(s)
- Katharine P. North
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA
| | - Douglas M. Mackay
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA
| | - Michael D. Annable
- Department of Environmental Engineering Sciences, University of Florida, 1600 SW Archer Rd, Gainesville, FL 32611, USA
| | - Kerry L. Sublette
- Center for Applied Biogeosciences, University of Tulsa, 800 South Tucker Dr, Tulsa, OK 74104, USA
| | - Greg Davis
- Microbial Insights, Inc., 2340 Stock Creek Blvd, Rockford, TN 37853, USA
| | - Reef B. Holland
- Department of Microbiology, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA
| | - Daniel Petersen
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA
| | - Kate M. Scow
- Department of Land, Air and Water Resources, University of California, Davis, 1 Shields Ave, Davis, CA 95616, USA
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11
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North KP, Mackay DM, Kayne JS, Petersen D, Rasa E, Rastegarzadeh L, Holland RB, Scow KM. In Situ Biotreatment of TBA with Recirculation/Oxygenation. GROUND WATER MONITORING & REMEDIATION 2012; 32:52-62. [PMID: 23358537 PMCID: PMC3555562 DOI: 10.1111/j.1745-6592.2011.01390.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants.
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Affiliation(s)
- Katharine P North
- Department of Land, Air and Water Resources, University of California, Davis
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12
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Internal loop photobiodegradation reactor (ILPBR) for accelerated degradation of sulfamethoxazole (SMX). Appl Microbiol Biotechnol 2012; 94:527-35. [DOI: 10.1007/s00253-011-3742-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Revised: 11/02/2011] [Accepted: 11/16/2011] [Indexed: 11/26/2022]
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13
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Rasa E, Chapman SW, Bekins BA, Fogg GE, Scow KM, Mackay DM. Role of back diffusion and biodegradation reactions in sustaining an MTBE/TBA plume in alluvial media. JOURNAL OF CONTAMINANT HYDROLOGY 2011; 126:235-47. [PMID: 22115089 PMCID: PMC3267905 DOI: 10.1016/j.jconhyd.2011.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 07/27/2011] [Accepted: 08/18/2011] [Indexed: 05/19/2023]
Abstract
A methyl tert-butyl ether (MTBE) / tert-butyl alcohol (TBA) plume originating from a gasoline spill in late 1994 at Vandenberg Air Force Base (VAFB) persisted for over 15 years within 200 feet of the original spill source. The plume persisted until 2010 despite excavation of the tanks and piping within months after the spill and excavations of additional contaminated sediments from the source area in 2007 and 2008. The probable history of MTBE concentrations along the plume centerline at its source was estimated using a wide variety of available information, including published details about the original spill, excavations and monitoring by VAFB consultants, and our own research data. Two-dimensional reactive transport simulations of MTBE along the plume centerline were conducted for a 20-year period following the spill. These analyses suggest that MTBE diffused from the thin anaerobic aquifer into the adjacent anaerobic silts and transformed to TBA in both aquifer and silt layers. The model reproduces the observation that after 2004 TBA was the dominant solute, diffusing back out of the silts into the aquifer and sustaining plume concentrations much longer than would have been the case in the absence of such diffusive exchange. Simulations also suggest that aerobic degradation of MTBE or TBA at the water table in the overlying silt layer significantly affected concentrations of MTBE and TBA by limiting the chemical mass available for back diffusion to the aquifer.
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Affiliation(s)
- Ehsan Rasa
- Department of Civil and Environmental Engineering, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA
- Tel.: +1 530 574 8193; fax: +1 530 752 1552.
| | - Steven W. Chapman
- School of Engineering, University of Guelph, 50 Stone Road East, Guelph, Ontario, N1G 2W1, Canada.
| | - Barbara A. Bekins
- U.S. Geological Survey, 345 Middlefield Rd, Menlo Park, California 94025, USA.
| | - Graham E. Fogg
- Department of Land, Air, and Water Resources, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA.
| | - Kate M. Scow
- Department of Land, Air, and Water Resources, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA.
| | - Douglas M. Mackay
- Department of Land, Air, and Water Resources, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA.
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Formation of alkenes via degradation of tert-alkyl ethers and alcohols by Aquincola tertiaricarbonis L108 and Methylibium spp. Appl Environ Microbiol 2011; 77:5981-7. [PMID: 21742915 DOI: 10.1128/aem.00093-11] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial degradation pathways of fuel oxygenates such as methyl tert-butyl and tert-amyl methyl ether (MTBE and TAME, respectively) have already been studied in some detail. However, many of the involved enzymes are still unknown, and possible side reactions have not yet been considered. In Aquincola tertiaricarbonis L108, Methylibium petroleiphilum PM1, and Methylibium sp. strain R8, we have now detected volatile hydrocarbons as by-products of the degradation of the tert-alkyl ether metabolites tert-butyl and tert-amyl alcohol (TBA and TAA, respectively). The alkene isobutene was formed only during TBA catabolism, while the beta and gamma isomers of isoamylene were produced only during TAA conversion. Both tert-alkyl alcohol degradation and alkene production were strictly oxygen dependent. However, the relative contribution of the dehydration reaction to total alcohol conversion increased with decreasing oxygen concentrations. In resting-cell experiments where the headspace oxygen content was adjusted to less than 2%, more than 50% of the TAA was converted to isoamylene. Isobutene formation from TBA was about 20-fold lower, reaching up to 4% alcohol turnover at low oxygen concentrations. It is likely that the putative tert-alkyl alcohol monooxygenase MdpJ, belonging to the Rieske nonheme mononuclear iron enzymes and found in all three strains tested, or an associated enzymatic step catalyzed the unusual elimination reaction. This was also supported by the detection of mdpJK genes in MTBE-degrading and isobutene-emitting enrichment cultures obtained from two treatment ponds operating at Leuna, Germany. The possible use of alkene formation as an easy-to-measure indicator of aerobic fuel oxygenate biodegradation in contaminated aquifers is discussed.
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Zhong W, Li Y, Sun K, Jin J, Li X, Zhang F, Chen J. Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1. JOURNAL OF HAZARDOUS MATERIALS 2011; 185:1249-1255. [PMID: 21112690 DOI: 10.1016/j.jhazmat.2010.10.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Revised: 10/05/2010] [Accepted: 10/12/2010] [Indexed: 05/30/2023]
Abstract
The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)).
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Affiliation(s)
- Weihong Zhong
- College of Biological and Environmental Engineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, Zhejiang Province 310032, China.
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16
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Linking low-level stable isotope fractionation to expression of the cytochrome P450 monooxygenase-encoding ethB gene for elucidation of methyl tert-butyl ether biodegradation in aerated treatment pond systems. Appl Environ Microbiol 2010; 77:1086-96. [PMID: 21148686 DOI: 10.1128/aem.01698-10] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multidimensional compound-specific stable isotope analysis (CSIA) was applied in combination with RNA-based molecular tools to characterize methyl tertiary (tert-) butyl ether (MTBE) degradation mechanisms occurring in biofilms in an aerated treatment pond used for remediation of MTBE-contaminated groundwater. The main pathway for MTBE oxidation was elucidated by linking the low-level stable isotope fractionation (mean carbon isotopic enrichment factor [ε(C)] of -0.37‰ ± 0.05‰ and no significant hydrogen isotopic enrichment factor [ε(H)]) observed in microcosm experiments to expression of the ethB gene encoding a cytochrome P450 monooxygenase able to catalyze the oxidation of MTBE in biofilm samples both from the microcosms and directly from the ponds. 16S rRNA-specific primers revealed the presence of a sequence 100% identical to that of Methylibium petroleiphilum PM1, a well-characterized MTBE degrader. However, neither expression of the mdpA genes encoding the alkane hydroxylase-like enzyme responsible for MTBE oxidation in this strain nor the related MTBE isotope fractionation pattern produced by PM1 could be detected, suggesting that this enzyme was not active in this system. Additionally, observed low inverse fractionation of carbon (ε(C) of +0.11‰ ± 0.03‰) and low fractionation of hydrogen (ε(H) of -5‰ ± 1‰) in laboratory experiments simulating MTBE stripping from an open surface water body suggest that the application of CSIA in field investigations to detect biodegradation may lead to false-negative results when volatilization effects coincide with the activity of low-fractionating enzymes. As shown in this study, complementary examination of expression of specific catabolic genes can be used as additional direct evidence for microbial degradation activity and may overcome this problem.
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Chan ML, Jaramillo G, Hristova KR, Horsley DA. Magnetic scanometric DNA microarray detection of methyl tertiary butyl ether degrading bacteria for environmental monitoring. Biosens Bioelectron 2010; 26:2060-6. [PMID: 20889328 DOI: 10.1016/j.bios.2010.09.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 08/27/2010] [Accepted: 09/02/2010] [Indexed: 11/25/2022]
Abstract
A magnetoresistive biosensing platform based on a single magnetic tunnel junction (MTJ) scanning probe and DNA microarrays labeled with magnetic particles has been developed to provide an inexpensive, sensitive and reliable detection of DNA. The biosensing platform was demonstrated on a DNA microarray assay for quantifying bacteria capable of degrading methyl tertiary butyl ether (MTBE), where concentrations as low as 10 pM were detectable. Synthetic probe bacterial DNA was immobilized on a microarray glass slide surface, hybridized with the 48 base pair long biotinylated target DNA and subsequently incubated with streptavidin-coated 2.8 μm diameter magnetic particles. The biosensing platform then makes use of a micron-sized MTJ sensor that was raster scanned across a 3 mm by 5 mm glass slide area to capture the stray magnetic field from the tagged DNA and extract two dimensional magnetic field images of the microarray. The magnetic field output is then averaged over each 100 μm diameter DNA array spot to extract the magnetic spot intensity, analogous to the fluorescence spot intensity used in conventional optical scanners. The magnetic scanning result is compared with results from a commercial laser scanner and particle coverage optical counting to demonstrate the dynamic range and linear sensitivity of the biosensing platform as a potentially inexpensive, sensitive and portable alternative for DNA microarray detection for field applications.
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Affiliation(s)
- Mei-Lin Chan
- Department of Mechanical and Aeronautical Engineering, University of California at Davis, Davis, CA 95616, United States
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18
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Baldwin BR, Biernacki A, Blair J, Purchase MP, Baker JM, Sublette K, Davis G, Ogles D. Monitoring gene expression to evaluate oxygen infusion at a gasoline-contaminated site. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:6829-6834. [PMID: 20681521 DOI: 10.1021/es101356t] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Increasingly, molecular biological tools, most notably quantitative polymerase chain reaction (qPCR), are being employed to provide a more comprehensive assessment of bioremediation of petroleum hydrocarbons and fuel oxygenates. While qPCR enumeration of key organisms or catabolic genes can aid in site management decisions, evaluation of site activities conducted to stimulate biodegradation would ideally include a direct measure of gene expression to infer activity. In the current study, reverse-transcriptase (RT) qPCR was used to monitor gene expression to evaluate the effectiveness of an oxygen infusion system to promote biodegradation of BTEX and MTBE. During system operation, dissolved oxygen (DO) levels at the infusion points were greater than 30 mg/L, contaminant concentrations decreased, and transcription of two aromatic oxygenase genes and Methylibium petroleiphilum PM1-like 16S rRNA copies increased by as many as 5 orders of magnitude. Moreover, aromatic oxygenase gene transcription and PM1 16s rRNA increased at downgradient locations despite low DO levels even during system operation. Conversely, target gene expression substantially decreased when the system was deactivated. RT-qPCR results also corresponded to increases in benzene and MTBE attenuation rates. Overall, monitoring gene expression complemented traditional groundwater analyses and conclusively demonstrated that the oxygen infusion system promoted BTEX and MTBE biodegradation.
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Affiliation(s)
- Brett R Baldwin
- Microbial Insights, Inc., Rockford, Tennessee 37853-3044, USA
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19
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Rosell M, Finsterbusch S, Jechalke S, Hübschmann T, Vogt C, Richnow HH. Evaluation of the effects of low oxygen concentration on stable isotope fractionation during aerobic MTBE biodegradation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2010; 44:309-315. [PMID: 19928956 DOI: 10.1021/es902491d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Laboratory experiments were performed with two aerobic MTBE degrading strains ( Methylibium sp. PM1 and Aquincola tertiaricarbonaris L108) in order to determine whether conditions of low oxygen availability, typically found in fuel-contaminated aquifers, can influence stable isotope fractionation of MTBE. Although single carbon and hydrogen enrichment factors of the two strains were not significantly or were only slightly (L108) affected by low oxygen concentrations (fully oxic incubation with initial 21% O2 in the headspace tested versus hypoxic conditions always <2% O2), the experiments showed indirect effects caused by competition interactions in mixed cultures. In a mixed culture of PM1 and L108 under oxic and even more so under hypoxic conditions, the total observed carbon isotope enrichment factor was significantly reduced, while hydrogen fractionation was not detectable. This indicates that the low fractionating model strain L108 is more competitive in degrading MTBE compared to strain PM1. Consistently, higher oxygen affinities during MTBE degradation were observed for strain L108. These first studies, conducted with resting cells, may explain the low isotope fractionation observed in some field studies that are not necessarily related to a lack of biodegradation.
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Affiliation(s)
- Mònica Rosell
- Department of Isotope Biogeochemistry, Department of Environmental Microbiology, Helmholtz Centre for Environmental Research-UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
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20
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Microbial communities and biodegradation in lab-scale BTEX-contaminated groundwater remediation using an oxygen-releasing reactive barrier. Bioprocess Biosyst Eng 2009; 33:383-91. [DOI: 10.1007/s00449-009-0336-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2009] [Accepted: 05/24/2009] [Indexed: 10/20/2022]
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21
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Involvement of a novel enzyme, MdpA, in methyl tert-butyl ether degradation in Methylibium petroleiphilum PM1. Appl Environ Microbiol 2008; 74:6631-8. [PMID: 18791002 DOI: 10.1128/aem.01192-08] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methylibium petroleiphilum PM1 is a well-characterized environmental strain capable of complete metabolism of the fuel oxygenate methyl tert-butyl ether (MTBE). Using a molecular genetic system which we established to study MTBE metabolism by PM1, we demonstrated that the enzyme MdpA is involved in MTBE removal, based on insertional inactivation and complementation studies. MdpA is constitutively expressed at low levels but is strongly induced by MTBE. MdpA is also involved in the regulation of tert-butyl alcohol (TBA) removal under certain conditions but is not directly responsible for TBA degradation. Phylogenetic comparison of MdpA to related enzymes indicates close homology to the short-chain hydrolyzing alkane hydroxylases (AH1), a group that appears to be a distinct subfamily of the AHs. The unique, substrate-size-determining residue Thr(59) distinguishes MdpA from the AH1 subfamily as well as from AlkB enzymes linked to MTBE degradation in Mycobacterium austroafricanum.
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22
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Drenovsky RE, Feris KP, Batten KM, Hristova K. New and Current Microbiological Tools for Ecosystem Ecologists: Towards a Goal of Linking Structure and Function. AMERICAN MIDLAND NATURALIST 2008. [DOI: 10.1674/0003-0031(2008)160[140:nacmtf]2.0.co;2] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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23
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Son A, Nichkova M, Dosev D, Kennedy IM, Hristova KR. Luminescent lanthanide nanoparticles as labels in DNA microarrays for quantification of methyl tertiary butyl ether degrading bacteria. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2008; 8:2463-7. [PMID: 18572664 PMCID: PMC3909105 DOI: 10.1166/jnn.2008.347] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report application of lanthanide nanoparticles for DNA quantification in a microarray platform as a substitute for conventional organic fluorophores. A non-PCR based DNA microarray assay for quantifying bacteria capable of biodegrading methyl tertiary-butyl ether (MTBE) was demonstrated. Probe DNA was immobilized on a glass surface, hybridized with biotinylated target DNA and subsequently incubated with Neutravidin-biofunctionalized nanoparticles. The fluorescence spot intensities, measured by a commercial laser scanner, show a linear relationship (R2 = 0.98) with bacterial 16S rDNA over a range of target DNA concentrations, while the background fluorescence remained low. In addition, nanoparticles fluorescence shows a stronger intensity than Quasar570 (Cy3). Present sensitivity of the assay is 10 pM of target DNA. The selectivity of the DNA-nanoparticle-probes to discriminate a non-target DNA with two base pairs mismatch in the 16S rDNA gene sequence was shown. The use of Eu:Gd2O3 nanoparticles as biolabels provides a relatively non-toxic, inexpensive, rapid and sensitive alternative to the materials currently used in DNA microarrays.
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Affiliation(s)
- Ahjeong Son
- Department of Land, Air, and Water Resources, University of California Davis, One Shields Avenue, Davis, California 95616, USA
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24
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Feris K, Mackay D, de Sieyes N, Chakraborty I, Einarson M, Hristova K, Scow K. Effect of ethanol on microbial community structure and function during natural attenuation of benzene, toluene, and o-xylene in a sulfate-reducing aquifer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:2289-2294. [PMID: 18504955 DOI: 10.1021/es702603q] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Ethanol (EtOH) is a commonly used fuel oxygenate in reformulated gasoline and is an alternative fuel and fuel supplement. Effects of EtOH release on aquifer microbial ecology and geochemistry have not been well characterized in situ. We performed a controlled field release of petroleum constituents (benzene (B), toluene (T), o-xylene (o-X) at approximately 1-3 mg/L each) with and without EtOH (approximately 500 mg/L). Mixed linear modeling (MLM) assessed effects on the microbial ecology of a naturally sulfidic aquifer and how the microbial community affected B, T, and o-X plume lengths and aquifer geochemistry. Changes in microbial community structure were determined by quantitative polymerase chain reaction (qPCR) targeting Bacteria, Archaea, and sulfate reducing bacteria (SRB); SRB were enumerated using a novel qPCR method targeting the adenosine-5'-phosphosulfate reductase gene. Bacterial and SRB densities increased with and without EtOH-amendment (1-8 orders of magnitude). Significant increases in Archaeal species richness; Archaeal cell densities (3-6 orders of magnitude); B, T, and o-X plume lengths; depletion of sulfate; and induction of methanogenic conditions were only observed with EtOH-amendment MLM supported the conclusion that EtOH-amendment altered microbial community structure and function, which in turn lowered the aquifer redox state and led to a reduction in bioattenuation rates of B, T, and o-X.
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Affiliation(s)
- Kevin Feris
- Department of Biology, Boise State University, Boise, Idaho, USA.
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25
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Cavagnaro TR, Jackson LE, Scow KM, Hristova KR. Effects of arbuscular mycorrhizas on ammonia oxidizing bacteria in an organic farm soil. MICROBIAL ECOLOGY 2007; 54:618-626. [PMID: 17955326 DOI: 10.1007/s00248-007-9212-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Revised: 01/11/2007] [Accepted: 01/17/2007] [Indexed: 05/25/2023]
Abstract
Arbuscular mycorrhizal fungi (AMF) are potentially important in nutrient cycling in agricultural soils and particularly in soils managed for organic production; little is known, however, about the interrelationships between AMF and other members of soil microbial communities. Ammonia oxidizing bacteria (AOB) are a trophic group of bacteria having an enormous impact on nitrogen availability in soils and are expected to be influenced by the presence of AMF. In a field study, we utilized a unique genetic system comprised of a mycorrhiza defective tomato mutant (named rmc) and its mycorrhiza wild-type progenitor (named 76RMYC+). We examined the effect of AMF by comparing AOB community composition and populations in soil containing roots of the two tomato genotypes in an organically managed soil. Responses of AOB to soil N and P amendments were also studied in the same experiment. Phylogenetic analysis of cloned AOB sequences, derived from excised denaturing gradient gel electrophoresis (DGGE) bands, revealed that the organic farm soil supported a diverse yet stable AOB community, which was neither influenced by mycorrhizal colonization of roots nor by N and P addition to the soil. Real-time TaqMan polymerase chain reaction (PCR) was used to quantify AOB population sizes and showed no difference between any of the treatments. An alternative real-time PCR protocol for quantification of AOB utilizing SYBR green yielded similar results as the TaqMan real-time PCR method, although with slightly lower resolution. This alternative method is advantageous in not requiring the detailed background information about AOB community composition required for adaptation of the TaqMan system for a new soil.
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Affiliation(s)
- T R Cavagnaro
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia.
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26
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Hristova KR, Schmidt R, Chakicherla AY, Legler TC, Wu J, Chain PS, Scow KM, Kane SR. Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol. Appl Environ Microbiol 2007; 73:7347-57. [PMID: 17890343 PMCID: PMC2168209 DOI: 10.1128/aem.01604-07] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.
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Affiliation(s)
- Krassimira R Hristova
- Department of Land Air and Water Resources, Plant and Environmental Sciences Building, University of California, Davis, Davis, CA 95616.
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27
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Raynal M, Pruden A. Aerobic MTBE biodegradation in the presence of BTEX by two consortia under batch and semi-batch conditions. Biodegradation 2007; 19:269-82. [PMID: 17562189 DOI: 10.1007/s10532-007-9133-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 05/11/2007] [Indexed: 10/23/2022]
Abstract
This study explores the effect of microbial consortium composition and reactor configuration on methyl tert-butyl ether (MTBE) biodegradation in the presence of benzene, toluene, ethylbenzene and p-xylenes(BTEX). MTBE biodegradation was monitored in the presence and absence of BTEX in duplicate batch reactors inoculated with distinct enrichment cultures: MTBE only (MO-originally enriched on MTBE) and/or MTBE BTEX (MB-originally enriched on MTBE and BTEX). The MO culture was also applied in a semi-batch reactor which received both MTBE and BTEX periodically in fresh medium after allowing cells to settle. The composition of the microbial consortia was explored using a combination of 16S rRNA gene cloning and quantitative polymerase chain reaction targeting the known MTBE-degrading strain PM1T. MTBE biodegradation was completely inhibited by BTEX in the batch reactors inoculated with the MB culture, and severely retarded in those inoculated with the MO culture (0.18+/-0.04 mg/L-day). In the semi-batch reactor, however, the MTBE biodegradation rate in the presence of BTEX was almost three times as high as in the batch reactors (0.48+/-0.2 mg/L-day), but still slower than MTBE biodegradation in the absence of BTEX in the MO-inoculated batch reactors (1.47+/-0.47 mg/L-day). A long lag phase in MTBE biodegradation was observed in batch reactors inoculated with the MB culture (20 days), but the ultimate rate was comparable to the MO culture (0.95+/-0.44 mg/L-day). Analysis of the cultures revealed that strain PM1T concentrations were lower in cultures that successfully biodegraded MTBE in the presence of BTEX. Also, other MTBE degraders, such as Leptothrix sp. and Hydrogenophaga sp. were found in these cultures. These results demonstrate that MTBE bioremediation in the presence of BTEX is feasible, and that culture composition and reactor configuration are key factors.
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Affiliation(s)
- M Raynal
- Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523, USA.
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28
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Galperin MY. Mycobacterial genomes for all tastes: from BCG to biodegradation of naphtalene and pyrene. Environ Microbiol 2007; 9:839-45. [PMID: 17359256 DOI: 10.1111/j.1462-2920.2007.01275.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Michael Y Galperin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD 20894, USA.
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29
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Kane SR, Chakicherla AY, Chain PSG, Schmidt R, Shin MW, Legler TC, Scow KM, Larimer FW, Lucas SM, Richardson PM, Hristova KR. Whole-genome analysis of the methyl tert-butyl ether-degrading beta-proteobacterium Methylibium petroleiphilum PM1. J Bacteriol 2007; 189:1931-45. [PMID: 17158667 PMCID: PMC1855728 DOI: 10.1128/jb.01259-06] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 11/29/2006] [Indexed: 11/20/2022] Open
Abstract
Methylibium petroleiphilum PM1 is a methylotroph distinguished by its ability to completely metabolize the fuel oxygenate methyl tert-butyl ether (MTBE). Strain PM1 also degrades aromatic (benzene, toluene, and xylene) and straight-chain (C(5) to C(12)) hydrocarbons present in petroleum products. Whole-genome analysis of PM1 revealed an approximately 4-Mb circular chromosome and an approximately 600-kb megaplasmid, containing 3,831 and 646 genes, respectively. Aromatic hydrocarbon and alkane degradation, metal resistance, and methylotrophy are encoded on the chromosome. The megaplasmid contains an unusual t-RNA island, numerous insertion sequences, and large repeated elements, including a 40-kb region also present on the chromosome and a 29-kb tandem repeat encoding phosphonate transport and cobalamin biosynthesis. The megaplasmid also codes for alkane degradation and was shown to play an essential role in MTBE degradation through plasmid-curing experiments. Discrepancies between the insertion sequence element distribution patterns, the distributions of best BLASTP hits among major phylogenetic groups, and the G+C contents of the chromosome (69.2%) and plasmid (66%), together with comparative genome hybridization experiments, suggest that the plasmid was recently acquired and apparently carries the genetic information responsible for PM1's ability to degrade MTBE. Comparative genomic hybridization analysis with two PM1-like MTBE-degrading environmental isolates (approximately 99% identical 16S rRNA gene sequences) showed that the plasmid was highly conserved (ca. 99% identical), whereas the chromosomes were too diverse to conduct resequencing analysis. PM1's genome sequence provides a foundation for investigating MTBE biodegradation and exploring the genetic regulation of multiple biodegradation pathways in M. petroleiphilum and other MTBE-degrading beta-proteobacteria.
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Affiliation(s)
- Staci R Kane
- Lawrence Livermore National Laboratory, Livermore, CA 94550, USA.
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Lin CW, Lai CY, Chen LH, Chiang WF. Microbial community structure during oxygen-stimulated bioremediation in phenol-contaminated groundwater. JOURNAL OF HAZARDOUS MATERIALS 2007; 140:221-9. [PMID: 16876942 DOI: 10.1016/j.jhazmat.2006.06.083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Revised: 05/19/2006] [Accepted: 06/20/2006] [Indexed: 05/11/2023]
Abstract
This research explored the changes in genetic diversity and spatial distribution of microbial communities in association with the changes in phenol concentration during a bioremediation process. Results using the traditional plate count method indicated an increase of average bacteria densities in groundwater from 10(4) to 10(7)CFUml(-1) initially to 10(7) to 10(9)CFUml(-1) after remediation. The diversity and stability of phenol-degrading bacterial communities were investigated by using single-strand-conformation polymorphism (SSCP) genetic profile analysis of 16S rDNA fragments amplified from groundwater samples. The molecular data showed a high degree of genetic similarity between communities from certain monitoring wells during the early phases of remediation, probably due to similar initial physical conditions among wells. Molecular signatures of several cultivated phenol-degrading bacterial strains could be seen in most groundwater profiles throughout the study period, suggesting that these strains were indigenous to the study site. It was also observed that the species diversity of these microbial communities increased as the phenol levels in the groundwater decreased during the 9-month study period, and recovered to the pre-treatment levels after the remediation program was completed.
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Affiliation(s)
- Chi-Wen Lin
- Department of Environmental Engineering, Da-Yeh University, 112 Shan-Jiau Road, Da-Tsuen, Changhua 515, Taiwan.
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Zhong WH, Chen JM, Lu Z, Chen DZ, Chen X. Aerobic degradation of methyl tert-butyl ether by a Proteobacteria strain in a closed culture system. J Environ Sci (China) 2007; 19:18-22. [PMID: 17913148 DOI: 10.1016/s1001-0742(07)60003-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The contamination of methyl tert-butyl ether (MTBE) in underground waters has become a widely concerned problem all over the world. In this study, a novel closed culture system with oxygen supplied by H2O2 was introduced for MTBE aerobic biodegradation. After 7 d, almost all MTBE was degraded by a pure culture, a member of beta-Proteobacteria named as PM1, in a closed system with oxygen supply, while only 40% MTBE was degraded in one without oxygen supply. Dissolved oxygen (DO) levels of the broth in closed systems respectively with and without H2O2 were about 5-6 and 4 mg/L. Higher DO may improve the activity of monooxygemase, which is the key enzyme of metabolic pathway from MTBE to tert-butyl alcohol and finally to CO2, and may result in the increase of the degrading activity of PM1 cell. The purge and trap GC-MS result of the broth in closed systems showed that tert-butyl alcohol, isopronol and acetone were the main intermediate products.
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Affiliation(s)
- Wei-hong Zhong
- College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310032, China.
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Nakatsu CH, Hristova K, Hanada S, Meng XY, Hanson JR, Scow KM, Kamagata Y. Methylibium petroleiphilum gen. nov., sp. nov., a novel methyl tert-butyl ether-degrading methylotroph of the Betaproteobacteria. Int J Syst Evol Microbiol 2006; 56:983-989. [PMID: 16627642 DOI: 10.1099/ijs.0.63524-0] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A Gram-negative, rod-shaped, motile, non-pigmented, facultative aerobe that grew optimally at pH 6.5 and 30 degrees C (strain PM1T) was isolated for its ability to completely degrade the gasoline additive methyl tert-butyl ether. Analysis of the 16S rRNA gene sequence indicated that this bacterium was a member of the class Betaproteobacteria in the Sphaerotilus-Leptothrix group. The 16S rRNA gene sequence identity to other genera in this group, Leptothrix, Aquabacterium, Roseateles, Sphaerotilus, Ideonella and Rubrivivax, ranged from 93 to 96 %. The chemotaxonomic data including Q-8 as the major quinone, C16 : 1omega7c and C16 : 0 as the major fatty acids and a DNA G+C content of 69 mol%, support the inclusion of strain PM1T in the class Betaproteobacteria. It differed from other members of the Sphaerotilus-Leptothrix group by being a facultative methylotroph that used methanol as a sole carbon source, and by also being able to grow heterotrophically in defined media containing ethanol, toluene, benzene, ethylbenzene and dihydroxybenzoates as sole carbon sources. On the basis of the morphological, physiological, biochemical and genetic information, a new genus and species, Methylibium petroleiphilum gen. nov., sp. nov., is proposed, with PM1T (=ATCC BAA-1232T=LMG 22953T) as the type strain.
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MESH Headings
- Base Composition
- Betaproteobacteria/classification
- Betaproteobacteria/cytology
- Betaproteobacteria/isolation & purification
- Betaproteobacteria/metabolism
- Biodegradation, Environmental
- DNA, Bacterial/chemistry
- DNA, Bacterial/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/genetics
- Fatty Acids/analysis
- Fatty Acids/isolation & purification
- Genes, rRNA
- Hydrocarbons/metabolism
- Leptothrix/genetics
- Methanol/metabolism
- Methyl Ethers/metabolism
- Microscopy
- Microscopy, Electron
- Molecular Sequence Data
- Phylogeny
- Quinones/analysis
- Quinones/isolation & purification
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/genetics
- Sequence Analysis, DNA
- Soil Microbiology
- Sphaerotilus/genetics
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Affiliation(s)
- Cindy H Nakatsu
- Department of Agronomy, Purdue University, West Lafayette, IN 47907-2054, USA
| | - Krassimira Hristova
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Satoshi Hanada
- Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Xian-Ying Meng
- Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
| | - Jessica R Hanson
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Kate M Scow
- Department of Microbiology, University of California, Davis, CA 95616, USA
- Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Yoichi Kamagata
- Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan
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Rohwerder T, Breuer U, Benndorf D, Lechner U, Müller RH. The alkyl tert-butyl ether intermediate 2-hydroxyisobutyrate is degraded via a novel cobalamin-dependent mutase pathway. Appl Environ Microbiol 2006; 72:4128-35. [PMID: 16751524 PMCID: PMC1489616 DOI: 10.1128/aem.00080-06] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Fuel oxygenates such as methyl and ethyl tert-butyl ether (MTBE and ETBE, respectively) are degraded only by a limited number of bacterial strains. The aerobic pathway is generally thought to run via tert-butyl alcohol (TBA) and 2-hydroxyisobutyrate (2-HIBA), whereas further steps are unclear. We have now demonstrated for the newly isolated beta-proteobacterial strains L108 and L10, as well as for the closely related strain CIP I-2052, that 2-HIBA was degraded by a cobalamin-dependent enzymatic step. In these strains, growth on substrates containing the tert-butyl moiety, such as MTBE, TBA, and 2-HIBA, was strictly dependent on cobalt, which could be replaced by cobalamin. Tandem mass spectrometry identified a 2-HIBA-induced protein with high similarity to a peptide whose gene sequence was found in the finished genome of the MTBE-degrading strain Methylibium petroleiphilum PM1. Alignment analysis identified it as the small subunit of isobutyryl-coenzyme A (CoA) mutase (ICM; EC 5.4.99.13), which is a cobalamin-containing carbon skeleton-rearranging enzyme, originally described only in Streptomyces spp. Sequencing of the genes of both ICM subunits from strain L108 revealed nearly 100% identity with the corresponding peptide sequences from M. petroleiphilum PM1, suggesting a horizontal gene transfer event to have occurred between these strains. Enzyme activity was demonstrated in crude extracts of induced cells of strains L108 and L10, transforming 2-HIBA into 3-hydroxybutyrate in the presence of CoA and ATP. The physiological and evolutionary aspects of this novel pathway involved in MTBE and ETBE metabolism are discussed.
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Affiliation(s)
- Thore Rohwerder
- Department of Environmental Microbiology, UFZ, Permoserstr. 15, 04318 Leipzig, Germany.
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35
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Lopes Ferreira N, Malandain C, Fayolle-Guichard F. Enzymes and genes involved in the aerobic biodegradation of methyl tert-butyl ether (MTBE). Appl Microbiol Biotechnol 2006; 72:252-62. [PMID: 16804692 DOI: 10.1007/s00253-006-0494-3] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2006] [Revised: 05/04/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
Fuel oxygenates, mainly methyl tert-butyl ether (MTBE) but also ethyl tert-butyl ether (ETBE), are added to gasoline in replacement of lead tetraethyl to enhance its octane index. Their addition also improves the combustion efficiency and therefore decreases the emission of pollutants (CO and hydrocarbons). On the other hand, MTBE, being highly soluble in water and recalcitrant to biodegradation, is a major pollutant of water in aquifers contaminated by MTBE-supplemented gasoline during accidental release. MTBE was shown to be degraded through cometabolic oxidation or to be used as a carbon and energy source by a few microorganisms. We have summarized the present state of knowledge about the microorganisms involved in MTBE degradation and the MTBE catabolic pathways. The role of the different enzymes is discussed as well as the rare and recent data concerning the genes encoding the enzymes involved in the MTBE pathway. The phylogeny of the microorganisms isolated for their capacity to grow on MTBE is also described.
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Affiliation(s)
- Nicolas Lopes Ferreira
- Biotechnology and Biomass Chemistry Department, Institut Français du Pétrole, 1-4 avenue de Bois-Préau, 92852, Rueil-Malmaison, France
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36
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Smith CJ, Nedwell DB, Dong LF, Osborn AM. Evaluation of quantitative polymerase chain reaction-based approaches for determining gene copy and gene transcript numbers in environmental samples. Environ Microbiol 2006; 8:804-15. [PMID: 16623738 DOI: 10.1111/j.1462-2920.2005.00963.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Quantitative polymerase chain reaction (Q-PCR) amplification is widely applied for determining gene and transcript numbers within environmental samples. This research evaluated Q-PCR reproducibility via TaqMan assays quantifying 16S rRNA gene and transcript numbers in sediments, within and between replicate Q-PCR assays. Intra-assay variation in 16S rRNA gene numbers in replicate DNA samples was low (coefficients of variation; CV from 3.2 to 5.2%). However, variability increased using replicated standard curves within separate Q-PCR assays (CV from 11.2% to 26%), indicating absolute comparison of gene numbers between Q-PCR assays was less reliable. 16S rRNA transcript quantification was evaluated using standard curves of diluted RNA or cDNA (before, or following, reverse transcription). These standard curves were statistically different with cDNA-derived curves giving higher r(2) values and Q-PCR efficiencies. Template concentrations used in Q-PCR also affected 16S rRNA gene and transcript numbers. For DNA, 10(-3) dilutions yielded higher gene numbers than 10(-1) and 10(-2) dilutions. Conversely, RNA template dilution reduced numbers of transcripts detected. Finally, different nucleic acid isolation methods also resulted in gene and transcript number variability. This research demonstrates Q-PCR determination of absolute numbers of genes and transcripts using environmental nucleic acids should be treated cautiously.
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Affiliation(s)
- Cindy J Smith
- Department of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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37
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Lopes Ferreira N, Maciel H, Mathis H, Monot F, Fayolle-Guichard F, Greer CW. Isolation and characterization of a new Mycobacterium austroafricanum strain, IFP 2015, growing on MTBE. Appl Microbiol Biotechnol 2005; 70:358-65. [PMID: 16028043 DOI: 10.1007/s00253-005-0074-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Revised: 06/23/2005] [Accepted: 06/24/2005] [Indexed: 11/30/2022]
Abstract
A new Mycobacterium austroafricanum strain, IFP 2015, growing on methyl tert-butyl ether (MTBE) as a sole carbon source was isolated from an MTBE-degrading microcosm inoculated with drain water of an MTBE-supplemented gasoline storage tank. M. austroafricanum IFP 2015 was able to grow on tert-butyl formate, tert-butyl alcohol (TBA) and alpha-hydroxyisobutyrate. 2-Methyl-1,2-propanediol was identified as the TBA oxidation product in M. austroafricanum IFP 2015 and in the previously isolated M. austroafricanum IFP 2012. M. austroafricanum IFP 2015 also degraded ethyl tert-butyl ether more rapidly than M. austroafricanum IFP 2012. Specific primers designed to monitor the presence of M. austroafricanum strains could be used as molecular tools to detect similar strains in MTBE-contaminated environment.
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38
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Zhang H, Logan BE, Regan JM, Achenbach LA, Bruns MA. Molecular assessment of inoculated and indigenous bacteria in biofilms from a pilot-scale perchlorate-reducing bioreactor. MICROBIAL ECOLOGY 2005; 49:388-98. [PMID: 16003477 DOI: 10.1007/s00248-004-0273-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2003] [Accepted: 04/10/2004] [Indexed: 05/03/2023]
Abstract
Bioremediation of perchlorate-contaminated groundwater can occur via bacterial reduction of perchlorate to chloride. Although perchlorate reduction has been demonstrated in bacterial pure cultures, little is known about the efficacy of using perchlorate-reducing bacteria as inoculants for bioremediation in the field. A pilot-scale, fixed-bed bioreactor containing plastic support medium was used to treat perchlorate-contaminated groundwater at a site in Southern California. The bioreactor was inoculated with a field-grown suspension of the perchlorate-respiring bacterium Dechlorosoma sp. strain KJ and fed groundwater containing indigenous bacteria and a carbon source amendment. Because the reactor was flushed weekly to remove accumulated biomass, only bacteria capable of growing in biofilms in the reactor were expected to survive. After 26 days of operation, perchlorate was not detected in bioreactor effluent. Perchlorate remained undetected by ion chromatography (detection limit 4 mug L(-1)) during 6 months of operation, after which the reactor was drained. Plastic medium was subsampled from top, middle, and bottom locations of the reactor for shipment on blue ice and storage at -80 degrees C prior to analysis. Microbial community DNA was extracted from successive washes of thawed biofilm material for PCR-based community profiling by 16S-23S ribosomal intergenic spacer analysis (RISA). No DNA sequences characteristic of strain KJ were recovered from any RISA bands. The most intense bands yielded DNA sequences with high similarities to Dechloromonas spp., a closely related but different genus of perchlorate-respiring bacteria. Additional sequences from RISA profiles indicated presence of representatives of the low G+C gram-positive bacteria and the Cytophaga-Flavobacterium-Bacteroides group. Confocal scanning laser microscopy and fluorescence in situ hybridization (FISH) were also used to examine biofilms using genus-specific 16S ribosomal RNA probes. FISH was more sensitive than RISA profiling in detecting possible survivors from the initial inoculum. FISH revealed that bacteria hybridizing to Dechlorosoma probes constituted <1% of all cells in the biofilms examined, except in the deepest portions where they represented 3-5%. Numbers of bacteria hybridizing to Dechloromonas probes decreased as biofilm depth increased, and they were most abundant at the biofilm surface (23% of all cells). These spatial distribution differences suggested persistence of low numbers of the inoculated strain Dechlorosoma sp. KJ in parts of the biofilm nearest to the plastic medium, concomitant with active colonization or growth by indigenous Dechloromonas spp. in the biofilm exterior. This study demonstrated the feasibility of post hoc analysis of frozen biofilms following completion of field remediation studies.
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Affiliation(s)
- H Zhang
- Department of Civil and Environmental Engineering, Pennsylvania State University, University Park, PA 16802, USA
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39
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Smith AE, Hristova K, Wood I, Mackay DM, Lory E, Lorenzana D, Scow KM. Comparison of Biostimulation versus Bioaugmentation with Bacterial Strain PM1 for Treatment of Groundwater Contaminated with Methyl
Tertiary
Butyl Ether (MTBE). ENVIRONMENTAL HEALTH PERSPECTIVES 2005; 113:317-22. [PMID: 15743721 PMCID: PMC1253758 DOI: 10.1289/ehp.6939] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Affiliation(s)
- Amanda E. Smith
- Department of Land, Air and Water Resources, University of California, Davis, California, USA
| | - Krassimira Hristova
- Department of Land, Air and Water Resources, University of California, Davis, California, USA
| | - Isaac Wood
- Department of Land, Air and Water Resources, University of California, Davis, California, USA
| | - Doug M. Mackay
- Department of Land, Air and Water Resources, University of California, Davis, California, USA
| | - Ernie Lory
- Port Hueneme Naval Construction Battalion Center, Oxnard, California, USA
| | - Dale Lorenzana
- Port Hueneme Naval Construction Battalion Center, Oxnard, California, USA
| | - Kate M. Scow
- Department of Land, Air and Water Resources, University of California, Davis, California, USA
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40
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Feris KP, Hristova K, Gebreyesus B, Mackay D, Scow KM. A shallow BTEX and MTBE contaminated aquifer supports a diverse microbial community. MICROBIAL ECOLOGY 2004; 48:589-600. [PMID: 15696392 DOI: 10.1007/s00248-004-0001-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2004] [Accepted: 06/02/2004] [Indexed: 05/24/2023]
Abstract
Microbial communities in subsurface environments are poorly characterized and the impacts of anthropogenic contamination on their structure and function have not been adequately addressed. The release of contaminant(s) to a previously unexposed environment is often hypothesized to decrease the diversity of the affected community. We characterized the structure of microbial communities along a gradient of benzene, toluene, ethylbenzene, and xylene (BTEX) and methyl-tert-butyl-ether (MTBE) contamination, resulting from a petroleum spill, within a shallow sandy aquifer at Vandenberg Air Force Base (VAFB) in Lompoc, CA. Differences in microbial community composition along the contaminant plume were assessed via a combinatorial approach utilizing denaturing gradient gel electrophoresis (DGGE), cloning and sequencing, intergenic transcribed spacer analysis (ITS), and comparative phylogenetic analysis of partial 16S rDNA sequences. Substantial bacterial sequence diversity, similar levels of species richness, and similar phylo-groups (including the Cytophaga-Flavobacterium-Bacteroidetes group and numerous members of the alpha-, beta-, gamma-, delta-, and epsilon-groups of the proteobacteria) were observed in both uncontaminated and contaminated regions of the aquifer. High-resolution measures (ITS fingerprinting and phylogenetic inference) readily separated communities impacted by the original petroleum spill (in source zone) from those in other parts of the aquifer and indicated that communities exposed to MTBE only were similar to communities in uncontaminated regions. Collectively, these data suggest that petroleum contamination alters microbial community structure at the species and subspecies level. Further study is required to determine whether these changes have an impact on the functioning of this subsurface ecosystem.
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Affiliation(s)
- K P Feris
- Land, Air, and Water Resources, The University of California, Davis, Davis, CA 95616, USA.
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41
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Davis LC, Erickson LE. A review of bioremediation and natural attenuation of MTBE. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/ep.10028] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Feris KP, Ramsey PW, Rillig M, Moore JN, Gannon JE, Holben WE. Determining rates of change and evaluating group-level resiliency differences in hyporheic microbial communities in response to fluvial heavy-metal deposition. Appl Environ Microbiol 2004; 70:4756-65. [PMID: 15294812 PMCID: PMC492400 DOI: 10.1128/aem.70.8.4756-4765.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prior field studies by our group have demonstrated a relationship between fluvial deposition of heavy metals and hyporheic-zone microbial community structure. Here, we determined the rates of change in hyporheic microbial communities in response to heavy-metal contamination and assessed group-level differences in resiliency in response to heavy metals. A controlled laboratory study was performed using 20 flowthrough river mesocosms and a repeated-measurement factorial design. A single hyporheic microbial community was exposed to five different levels of an environmentally relevant metal treatment (0, 4, 8, 16, and 30% sterilized contaminated sediments). Community-level responses were monitored at 1, 2, 4, 8, and 12 weeks via denaturing gradient gel electrophoresis and quantitative PCR using group-specific primer sets for indigenous populations most closely related to the alpha-, beta-, and gamma-proteobacteria. There was a consistent, strong curvilinear relationship between community composition and heavy-metal contamination (R(2) = 0.83; P < 0.001), which was evident after only 7 days of metal exposure (i.e., short-term response). The abundance of each phylogenetic group was negatively affected by the heavy-metal treatments; however, each group recovered from the metal treatments to a different extent and at a unique rate during the course of the experiment. The structure of hyporheic microbial communities responded rapidly and at contamination levels an order of magnitude lower than those shown to elicit a response in aquatic macroinvertebrate assemblages. These studies indicate that hyporheic microbial communities are a sensitive and useful indicator of heavy-metal contamination in streams.
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Affiliation(s)
- Kevin P Feris
- Microbial Ecology Program, Division of Biological Sciences, The University of Montana, Missoula, MT 59812-1006, USA
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Okano Y, Hristova KR, Leutenegger CM, Jackson LE, Denison RF, Gebreyesus B, Lebauer D, Scow KM. Application of real-time PCR to study effects of ammonium on population size of ammonia-oxidizing bacteria in soil. Appl Environ Microbiol 2004; 70:1008-16. [PMID: 14766583 PMCID: PMC348910 DOI: 10.1128/aem.70.2.1008-1016.2004] [Citation(s) in RCA: 332] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ammonium oxidation by autotrophic ammonia-oxidizing bacteria (AOB) is a key process in agricultural and natural ecosystems and has a large global impact. In the past, the ecology and physiology of AOB were not well understood because these organisms are notoriously difficult to culture. Recent applications of molecular techniques have advanced our knowledge of AOB, but the necessity of using PCR-based techniques has made quantitative measurements difficult. A quantitative real-time PCR assay targeting part of the ammonia-monooxygenase gene (amoA) was developed to estimate AOB population size in soil. This assay has a detection limit of 1.3 x 10(5) cells/g of dry soil. The effect of the ammonium concentration on AOB population density was measured in soil microcosms by applying 0, 1.5, or 7.5 mM ammonium sulfate. AOB population size and ammonium and nitrate concentrations were monitored for 28 days after (NH4)2SO4 application. AOB populations in amended treatments increased from an initial density of approximately 4 x 10(6) cells/g of dry soil to peak values (day 7) of 35 x 10(6) and 66 x 10(6) cells/g of dry soil in the 1.5 and 7.5 mM treatments, respectively. The population size of total bacteria (quantified by real-time PCR with a universal bacterial probe) remained between 0.7 x 10(9) and 2.2 x 10(9) cells/g of soil, regardless of the ammonia concentration. A fertilization experiment was conducted in a tomato field plot to test whether the changes in AOB density observed in microcosms could also be detected in the field. AOB population size increased from 8.9 x 10(6) to 38.0 x 10(6) cells/g of soil by day 39. Generation times were 28 and 52 h in the 1.5 and 7.5 mM treatments, respectively, in the microcosm experiment and 373 h in the ammonium treatment in the field study. Estimated oxidation rates per cell ranged initially from 0.5 to 25.0 fmol of NH4+ h(-1) cell(-1) and decreased with time in both microcosms and the field. Growth yields were 5.6 x 10(6), 17.5 x 10(6), and 1.7 x 10(6) cells/mol of NH4+ in the 1.5 and 7.5 mM microcosm treatments and the field study, respectively. In a second field experiment, AOB population size was significantly greater in annually fertilized versus unfertilized soil, even though the last ammonium application occurred 8 months prior to measurement, suggesting a long-term effect of ammonium fertilization on AOB population size.
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Affiliation(s)
- Yutaka Okano
- Department of Land, Air, and Water Resources, University of California, Davis, California 95616, USA
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Johnson EL, Smith CA, O'Reilly KT, Hyman MR. Induction of methyl tertiary butyl ether (MTBE)-oxidizing activity in Mycobacterium vaccae JOB5 by MTBE. Appl Environ Microbiol 2004; 70:1023-30. [PMID: 14766585 PMCID: PMC348811 DOI: 10.1128/aem.70.2.1023-1030.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Alkane-grown cells of Mycobacterium vaccae JOB5 cometabolically degrade the gasoline oxygenate methyl tertiary butyl ether (MTBE) through the activities of an alkane-inducible monooxygenase and other enzymes in the alkane oxidation pathway. In this study we examined the effects of MTBE on the MTBE-oxidizing activity of M. vaccae JOB5 grown on diverse nonalkane substrates. Carbon-limited cultures were grown on glycerol, lactate, several sugars, and tricarboxylic acid cycle intermediates, both in the presence and absence of MTBE. In all MTBE-containing cultures, MTBE consumption occurred and tertiary butyl alcohol (TBA) and tertiary butyl formate accumulated in the culture medium. Acetylene, a specific inactivator of alkane- and MTBE-oxidizing activities, fully inhibited MTBE consumption and product accumulation but had no other apparent effects on culture growth. The MTBE-dependent stimulation of MTBE-oxidizing activity in fructose- and glycerol-grown cells was saturable with respect to MTBE concentration (50% saturation level = 2.4 to 2.75 mM), and the onset of MTBE oxidation in glycerol-grown cells was inhibited by both rifampin and chloramphenicol. Other oxygenates (TBA and tertiary amyl methyl ether) also induced the enzyme activity required for their own degradation in glycerol-grown cells. Presence of MTBE also promoted MTBE oxidation in cells grown on organic acids, compounds that are often found in anaerobic, gasoline-contaminated environments. Experiments with acid-grown cells suggested induction of MTBE-oxidizing activity by MTBE is subject to catabolite repression. The results of this study are discussed in terms of their potential implications towards our understanding of the role of cometabolism in MTBE and TBA biodegradation in gasoline-contaminated environments.
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Affiliation(s)
- Erika L Johnson
- Department of Microbiology, North Carolina State University, Raleigh, North Carolina 27695, USA
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Schmidt TC, Schirmer M, Weiss H, Haderlein SB. Microbial degradation of methyl tert-butyl ether and tert-butyl alcohol in the subsurface. JOURNAL OF CONTAMINANT HYDROLOGY 2004; 70:173-203. [PMID: 15134874 DOI: 10.1016/j.jconhyd.2003.09.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2002] [Revised: 08/29/2003] [Accepted: 09/18/2003] [Indexed: 05/24/2023]
Abstract
The fate of fuel oxygenates such as methyl tert-butyl ether (MTBE) in the subsurface is governed by their degradability under various redox conditions. The key intermediate in degradation of MTBE and ethyl tert-butyl ether (ETBE) is tert-butyl alcohol (TBA) which was often found as accumulating intermediate or dead-end product in lab studies using microcosms or isolated cell suspensions. This review discusses in detail the thermodynamics of the degradation processes utilizing various terminal electron acceptors, and the aerobic degradation pathways of MTBE and TBA. It summarizes the present knowledge on MTBE and TBA degradation gained from either microcosm or pure culture studies and emphasizes the potential of compound-specific isotope analysis (CSIA) for identification and quantification of degradation processes of slowly biodegradable pollutants such as MTBE and TBA. Microcosm studies demonstrated that MTBE and TBA may be biodegradable under oxic and nearly all anoxic conditions, although results of various studies are often contradictory, which suggests that site-specific conditions are important parameters. So far, TBA degradation has not been shown under methanogenic conditions and it is currently widely accepted that TBA is a recalcitrant dead-end product of MTBE under these conditions. Reliable in situ degradation rates for MTBE and TBA under various geochemical conditions are not yet available. Furthermore, degradation pathways under anoxic conditions have not yet been elucidated. All pure cultures capable of MTBE or TBA degradation isolated so far use oxygen as terminal electron acceptor. In general, compared with hydrocarbons present in gasoline, fuel oxygenates biodegrade much slower, if at all. The presence of MTBE and related compounds in groundwater therefore frequently limits the use of in situ biodegradation as remediation option at gasoline-contaminated sites. Though degradation of MTBE and TBA in field studies has been reported under oxic conditions, there is hardly any evidence of substantial degradation in the absence of oxygen. The increasing availability of field data from CSIA will foster our understanding and may even allow the quantification of degradation of these recalcitrant compounds. Such information will help to elucidate the crucial factors of site-specific biogeochemical conditions that govern the capability of intrinsic oxygenate degradation.
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Affiliation(s)
- Torsten C Schmidt
- Environmental Mineralogy, Center for Applied Geoscience, Eberhard-Karls-University of Tuebingen, Wilhelmstr. 56, D-72074, Germany.
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Abstract
Bioremediation has the potential to restore contaminated environments inexpensively yet effectively, but a lack of information about the factors controlling the growth and metabolism of microorganisms in polluted environments often limits its implementation. However, rapid advances in the understanding of bioremediation are on the horizon. Researchers now have the ability to culture microorganisms that are important in bioremediation and can evaluate their physiology using a combination of genome-enabled experimental and modelling techniques. In addition, new environmental genomic techniques offer the possibility for similar studies on as-yet-uncultured organisms. Combining models that can predict the activity of microorganisms that are involved in bioremediation with existing geochemical and hydrological models should transform bioremediation from a largely empirical practice into a science.
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Affiliation(s)
- Derek R Lovley
- Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, USA.
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