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Woern C, Grossmann L. Microbial gas fermentation technology for sustainable food protein production. Biotechnol Adv 2023; 69:108240. [PMID: 37647973 DOI: 10.1016/j.biotechadv.2023.108240] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/01/2023]
Abstract
The development of novel, sustainable, and robust food production technologies represents one of the major pillars to address the most significant challenges humanity is going to face on earth in the upcoming decades - climate change, population growth, and resource depletion. The implementation of microfoods, i.e., foods formulated with ingredients from microbial cultivation, into the food supply chain has a huge potential to contribute towards energy-efficient and nutritious food manufacturing and represents a means to sustainably feed a growing world population. This review recapitulates and assesses the current state in the establishment and usage of gas fermenting bacteria as an innovative feedstock for protein production. In particular, we focus on the most promising representatives of this taxon: the hydrogen-oxidizing bacteria (hydrogenotrophs) and the methane-oxidizing bacteria (methanotrophs). These unicellular microorganisms can aerobically metabolize gaseous hydrogen and methane, respectively, to provide the required energy for building up cell material. A protein yield over 70% in the dry matter cell mass can be reached with no need for arable land and organic substrates making it a promising alternative to plant- and animal-based protein sources. We illuminate the holistic approach to incorporate protein extracts obtained from the cultivation of gas fermenting bacteria into microfoods. Herein, the fundamental properties of the bacteria, cultivation methods, downstream processing, and potential food applications are discussed. Moreover, this review covers existing and future challenges as well as sustainability aspects associated with the production of microbial protein through gas fermentation.
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Affiliation(s)
- Carlos Woern
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA
| | - Lutz Grossmann
- Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA.
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Hwangbo M, Shao Y, Hatzinger PB, Chu KH. Acidophilic methanotrophs: Occurrence, diversity, and possible bioremediation applications. ENVIRONMENTAL MICROBIOLOGY REPORTS 2023. [PMID: 37041665 DOI: 10.1111/1758-2229.13156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 06/19/2023]
Abstract
Methanotrophs have been identified and isolated from acidic environments such as wetlands, acidic soils, peat bogs, and groundwater aquifers. Due to their methane (CH4 ) utilization as a carbon and energy source, acidophilic methanotrophs are important in controlling the release of atmospheric CH4 , an important greenhouse gas, from acidic wetlands and other environments. Methanotrophs have also played an important role in the biodegradation and bioremediation of a variety of pollutants including chlorinated volatile organic compounds (CVOCs) using CH4 monooxygenases via a process known as cometabolism. Under neutral pH conditions, anaerobic bioremediation via carbon source addition is a commonly used and highly effective approach to treat CVOCs in groundwater. However, complete dechlorination of CVOCs is typically inhibited at low pH. Acidophilic methanotrophs have recently been observed to degrade a range of CVOCs at pH < 5.5, suggesting that cometabolic treatment may be an option for CVOCs and other contaminants in acidic aquifers. This paper provides an overview of the occurrence, diversity, and physiological activities of methanotrophs in acidic environments and highlights the potential application of these organisms for enhancing contaminant biodegradation and bioremediation.
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Affiliation(s)
- Myung Hwangbo
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
| | - Yiru Shao
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
| | - Paul B Hatzinger
- Aptim Federal Services, LLC, 17 Princess Road, Lawrenceville, New Jersey, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, Texas, USA
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Baskaran B, Gill TM, Furst AL. An Improved Spectrophotometric Method for Toluene-4-Monooxygenase Activity. Chemistry 2023; 29:e202203322. [PMID: 36593585 PMCID: PMC10423644 DOI: 10.1002/chem.202203322] [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: 10/26/2022] [Revised: 12/28/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023]
Abstract
Monooxygenases, an important class of enzymes, have been the subject of enzyme engineering due to their high activity and versatile substrate scope. Reactions performed by these biocatalysts have long been monitored by a colorimetric method involving the coupling of a dye precursor to naphthalene hydroxylation products generated by the enzyme. Despite the popularity of this method, we found the dye product to be unstable, preventing quantitative readout. By incorporating an extraction step to solubilize the dye produced, we have improved this assay to the point where quantitation of enzyme activity is possible. Further, by incorporating spectral deconvolution, we have, for the first time, enabled independent quantification of the two possible regioisomeric products: 1-naphthol and 2-naphthol. Previously, such analysis was only possible with chromatographic separation, increasing the cost and complexity of analysis. The efficacy of our improved workflow was evaluated by monitoring the activity of a toluene-4-monooxygenase enzyme from Pseudomonas mendocina KR-1. Our colorimetric regioisomer quantification was found to be consistent with chromatographic analysis by HPLC. The development and validation of a quantitative colorimetric assay for monooxygenase activity that enables regioisomeric distinction and quantification represents a significant advance in analytical methods to monitor enzyme activity. By maintaining facile, low-cost, high-throughput readout while incorporating quantification, this assay represents an important alternative to more expensive chromatographic quantification techniques.
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Affiliation(s)
- Barathkumar Baskaran
- Deparment of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Thomas M. Gill
- Deparment of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Ariel L. Furst
- Deparment of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
- Center for Environmental Health Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139
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An Overview on Methanotrophs and the Role of Methylosinus trichosporium OB3b for Biotechnological Applications. BIOTECHNOL BIOPROC E 2022. [DOI: 10.1007/s12257-022-0046-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Naizabekov S, Lee EY. Genome-Scale Metabolic Model Reconstruction and in Silico Investigations of Methane Metabolism in Methylosinus trichosporium OB3b. Microorganisms 2020; 8:microorganisms8030437. [PMID: 32244934 PMCID: PMC7144005 DOI: 10.3390/microorganisms8030437] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/16/2020] [Accepted: 03/19/2020] [Indexed: 01/09/2023] Open
Abstract
Methylosinus trichosporium OB3b is an obligate aerobic methane-utilizing alpha-proteobacterium. Since its isolation, M. trichosporium OB3b has been established as a model organism to study methane metabolism in type II methanotrophs. M. trichosporium OB3b utilizes soluble and particulate methane monooxygenase (sMMO and pMMO respectively) for methane oxidation. While the source of electrons is known for sMMO, there is less consensus regarding electron donor to pMMO. To investigate this and other questions regarding methane metabolism, the genome-scale metabolic model for M. trichosporium OB3b (model ID: iMsOB3b) was reconstructed. The model accurately predicted oxygen: methane molar uptake ratios and specific growth rates on nitrate-supplemented medium with methane as carbon and energy source. The redox-arm mechanism which links methane oxidation with complex I of electron transport chain has been found to be the most optimal mode of electron transfer. The model was also qualitatively validated on ammonium-supplemented medium indicating its potential to accurately predict methane metabolism in different environmental conditions. Finally, in silico investigations regarding flux distribution in central carbon metabolism of M. trichosporium OB3b were performed. Overall, iMsOB3b can be used as an organism-specific knowledgebase and a platform for hypothesis-driven theoretical investigations of methane metabolism.
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Li H, Chi Z, Li J, Wu H, Yan B. Bacterial community structure and function in soils from tidal freshwater wetlands in a Chinese delta: Potential impacts of salinity and nutrient. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 696:134029. [PMID: 31470319 DOI: 10.1016/j.scitotenv.2019.134029] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 08/19/2019] [Accepted: 08/20/2019] [Indexed: 05/16/2023]
Abstract
Microorganisms in tidal freshwater wetlands affect biogeochemical cycling of nutrients, but the structures and functions of the wetland communities change due to natural and anthropogenic stresses. Soil samples were collected along a 350-m sampling belt in typical tidal freshwater wetlands of Yellow River Delta to investigate nutrient distributions, bacterial community structures and potential metabolic functions under tide and runoff stress by high-throughput sequencing and PICRUSt analysis. The total nitrogen (TN) contents varied greatly while total phosphorous (TP) contents were relatively stable. The bacterial community structures and predicted functions varied along a 350-m sampling belt. Some sulfate-reducing bacteria, nitrifying bacteria, Marmoricola, unclassified_f_Salinisphaeraceae and Oceanococcus exhibited a decreased trend with increasing distances far away from the river bank (B-0m). However, Salinisphaera was more dominant far away from the river bank (B-350m), indicating the stronger tolerance degree under salt stress. Marinobacterium and Marinobacter could be widely detected from B-0m to B-350m, demonstrating that those bacteria could tolerate a broad range of salinity and have its exceptional adaptation capacities. Redundancy analysis (RDA) indicated that nutrient and salinity played an important role in shaping bacterial community composition. NH4+-N and AP were the key factors in explaining the variance of the genus level. Predicted by PICRUSt analysis, nitrogen fixation (NF), nitrogen mineralization (NM), denitrification and dissimilatory nitrate reduction to ammonium (DNRA) might be the dominant processes of nitrogen metabolism and related genes abundance were abundant in tidal freshwater wetland soils. These findings could provide new insights into the prevention and control of potential nutrient pollution in tidal freshwater wetlands under the dual stress of tide and runoff.
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Affiliation(s)
- Huai Li
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Zifang Chi
- Key Lab of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, PR China.
| | - Jiuling Li
- Advanced Water Management Centre, The University of Queensland, St. Lucia, Brisbane, Queensland 4072, Australia
| | - Haitao Wu
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
| | - Baixing Yan
- Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, PR China
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Zhang T, Zhou J, Wang X, Zhang Y. Poly-β-hydroxybutyrate Production by Methylosinus trichosporium OB3b at Different Gas-phase Conditions. IRANIAN JOURNAL OF BIOTECHNOLOGY 2019; 17:e1866. [PMID: 31457042 PMCID: PMC6697861 DOI: 10.21859/ijb.1866] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The utilization of methane for production of Poly-β-hydroxybutyrate (PHB) not only cuts the emissions of greenhouse gases but also greatly reduces PHB production cost. OBJECTIVES The aim of this study was to determine the effects of gas-phase conditions on PHB production by Methylosinus trichosporium OB3b. MATERIALS AND METHODS Bacterial cultivation and PHB production were conducted in a series of sealed serum bottles. Nitrogen-free mineral salts medium was used to induce PHB production in the presence or absence of N2 in the headspace. RESULTS In the absence of N2, the highest PHB content (i.e., 52.9% of the dry cell weight with a PHB concentration of 814.3 mg.L-1) was obtained at a ratio of CH4:O2=2:1. Further study at different O2 concentrations with a fixed CH4 partial pressure in absence of N2 showed that PHB accumulation by methanotroph could be tolerated high oxygen partial pressure and its respond to the variation of the oxygen concentration depends on the methane partial pressure. In presence of N2, with headspace gas replenished only when oxygen was almost depleted, the degradation of intracellular PHB has appeared. In the regimen of updating headspace gas at the point when the PHB content began to decrease, the highest PHB content (i.e., 55.5% of the dry cell weight with 901.8 mg.L-1 PHB concentration and 12.5 mg.L-1.h-1PHB productivity) was obtained at 0.2 atm O2 and PHB accumulation was depressed with an oxygen concentration greater than 0.3 atm. CONCLUSIONS The methanotroph responses differentially to the increase in the oxygen partial pressure with regard to PHB accumulation either in the presence or in the absence of N2.
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Affiliation(s)
- Tingting Zhang
- School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
| | - Xiaowei Wang
- School of Chemical Engineering and Energy, Zhengzhou University, Zhengzhou, China
| | - Yu Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian, China
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Lai CY, Lv PL, Dong QY, Yeo SL, Rittmann BE, Zhao HP. Bromate and Nitrate Bioreduction Coupled with Poly-β-hydroxybutyrate Production in a Methane-Based Membrane Biofilm Reactor. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:7024-7031. [PMID: 29785845 DOI: 10.1021/acs.est.8b00152] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
This work demonstrates bromate (BrO3-) reduction in a methane (CH4)-based membrane biofilm reactor (MBfR), and it documents contrasting impacts of nitrate (NO3-) on BrO3- reduction, as well as formation of poly-β-hydroxybutyrate (PHB), an internal C- and electron-storage material. When the electron donor, CH4, was in ample supply, NO3- enhanced BrO3- reduction by stimulating the growth of denitrifying bacteria ( Meiothermus, Comamonadaceae, and Anaerolineaceae) able to reduce BrO3- and NO3- simultaneously. This was supported by increases in denitrifying enzymes (e.g., nitrate reductase, nitrite reductase, nitrous-oxide reductase, and nitric-oxide reductase) through quantitative polymerase chain reaction (qPCR) analysis and metagenomic prediction of these functional genes. When the electron donor was in limited supply, NO3- was the preferred electron acceptor over BrO3- due to competition for the common electron donor; this was supported by the significant oxidation of stored PHB when NO3- was high enough to cause electron-donor limitation. Methanotrophs (e.g., Methylocystis, Methylomonas, and genera within Comamonadaceae) were implicated as the main PHB producers in the biofilms, and their ability to oxidize PHB mitigated the impacts of competition for CH4.
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Affiliation(s)
- Chun-Yu Lai
- College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China
| | - Pan-Long Lv
- College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China
| | - Qiu-Yi Dong
- College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China
| | - Shi Lei Yeo
- College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China
| | - Bruce E Rittmann
- Biodesign Swette Center for Environmental Biotechnology , Arizona State University , P.O. Box 875701, Tempe , Arizona 85287-5701 , United States
| | - He-Ping Zhao
- College of Environmental and Resource Science , Zhejiang University , Hangzhou 310027 , China
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Taylor A, Molzahn P, Bushnell T, Cheney C, LaJeunesse M, Azizian M, Semprini L. Immobilization of Methylosinus trichosporium OB3b for methanol production. ACTA ACUST UNITED AC 2018; 45:201-211. [DOI: 10.1007/s10295-018-2010-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 01/10/2018] [Indexed: 11/29/2022]
Abstract
Abstract
Due to the natural gas boom in North America, there is renewed interest in the production of other chemical products from methane. We investigated the feasibility of immobilizing the obligate methanotrophic bacterium Methylosinus trichosporium OB3b in alginate beads, and selectively inactivating methanol dehydrogenase (MDH) with cyclopropane to produce methanol. In batch cultures and in semi-continuous flow columns, the exposure of alginate-immobilized cells to cyclopropane or cyclopropanol resulted in the loss of the majority of MDH activity (> 80%), allowing methanol to accumulate to significant concentrations while retaining all of M. trichosporium OB3b’s methane monooxygenase capacity. Thereafter, the efficiency of methanol production fell due to recovery of most of the MDH activity; however, subsequent inhibition periods resulted in renewed methanol production efficiency, and immobilized cells retained methane-oxidizing activity for at least 14 days.
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Affiliation(s)
- Anne Taylor
- 0000 0001 2112 1969 grid.4391.f Department of Crop and Soil Science Oregon State University 3017 Agricultural Life Science Building 97331 Corvallis OR USA
| | - Paige Molzahn
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
| | - Tanner Bushnell
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
| | - Clint Cheney
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
| | - Monique LaJeunesse
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
| | - Mohamad Azizian
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
| | - Lewis Semprini
- 0000 0001 2112 1969 grid.4391.f Department of Chemical Biological and Environmental Engineering Oregon State University Corvallis OR USA
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Zhang T, Zhou J, Wang X, Zhang Y. Coupled effects of methane monooxygenase and nitrogen source on growth and poly-β-hydroxybutyrate (PHB) production of Methylosinus trichosporium OB3b. J Environ Sci (China) 2017; 52:49-57. [PMID: 28254057 DOI: 10.1016/j.jes.2016.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 03/03/2016] [Accepted: 03/07/2016] [Indexed: 06/06/2023]
Abstract
The coupled effects of nitrogen source and methane monooxygenase (MMO) on the growth and poly-β-hydroxybutyrate (PHB) accumulation capacity of methanotrophs were explored. The ammonia-supplied methanotrophs expressing soluble MMO (sMMO) grew at the highest rate, while N2-fixing bacteria expressing particulate MMO (pMMO) grew at the lowest rate. Further study showed that more hydroxylamine and nitrite was formed by ammonia-supplied bacteria containing pMMO, which might cause their slightly lower growth rate. The highest PHB content (51.0%) was obtained under nitrogen-limiting conditions with the inoculation of nitrate-supplied bacteria containing pMMO. Ammonia-supplied bacteria also accumulated a higher content of PHB (45.2%) with the expression of pMMO, while N2-fixing bacteria containing pMMO only showed low PHB production capacity (32.1%). The maximal PHB contents of bacteria expressing sMMO were low, with no significant change under different nitrogen source conditions. The low MMO activity, low cell growth rate and low PHB production capacity of methanotrophs continuously cultivated with N2 with the expression of pMMO were greatly improved in the cyclic NO3-N2 cultivation regime, indicating that long-term deficiency of nitrogen sources was detrimental to the activity of methanotrophs expressing pMMO.
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Affiliation(s)
- Tingting Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Jiti Zhou
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
| | - Xiaowei Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
| | - Yu Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering, School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China
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Mulla SI, Sun Q, Hu A, Wang Y, Ashfaq M, Eqani SAMAS, Yu CP. Evaluation of Sulfadiazine Degradation in Three Newly Isolated Pure Bacterial Cultures. PLoS One 2016; 11:e0165013. [PMID: 27755578 PMCID: PMC5068754 DOI: 10.1371/journal.pone.0165013] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 10/05/2016] [Indexed: 11/24/2022] Open
Abstract
This study is aimed to assess the biodegradation of sulfadiazine (SDZ) and characterization of heavy metal resistance in three pure bacterial cultures and also their chemotactic response towards 2-aminopyrimidine. The bacterial cultures were isolated from pig manure, activated sludge and sediment samples, by enrichment technique on SDZ (6 mg L-1). Based on the 16S rRNA gene sequence analysis, the microorganisms were identified within the genera of Paracoccus, Methylobacterium and Kribbella, which were further designated as SDZ-PM2-BSH30, SDZ-W2-SJ40 and SDZ-3S-SCL47. The three identified pure bacterial strains degraded up to 50.0, 55.2 and 60.0% of SDZ (5 mg L-1), respectively within 290 h. On the basis of quadrupole time-of-flight mass spectrometry and high performance liquid chromatography, 2-aminopyrimidine and 4-hydroxy-2-aminopyrimidine were identified as the main intermediates of SDZ biodegradation. These bacteria were also able to degrade the metabolite, 2-aminopyrimidine, of the SDZ. Furthermore, SDZ-PM2-BSH30, SDZ-W2-SJ40 and SDZ-3S-SCL47 also showed resistance to various heavy metals like copper, cadmium, chromium, cobalt, lead, nickel and zinc. Additionally, all three bacteria exhibited positive chemotaxis towards 2-aminopyrimidine based on the drop plate method and capillary assay. The results of this study advanced our understanding about the microbial degradation of SDZ, which would be useful towards the future SDZ removal in the environment.
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Affiliation(s)
- Sikandar I. Mulla
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Qian Sun
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Anyi Hu
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Yuwen Wang
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | - Muhammad Ashfaq
- CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | | | - Chang-Ping Yu
- Graduate Institute of Environmental Engineering, National Taiwan University, Taipei 106, Taiwan
- * E-mail:
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Mulla SI, Hu A, Wang Y, Sun Q, Huang SL, Wang H, Yu CP. Degradation of triclocarban by a triclosan-degrading Sphingomonas sp. strain YL-JM2C. CHEMOSPHERE 2016; 144:292-296. [PMID: 26364219 DOI: 10.1016/j.chemosphere.2015.08.034] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 08/06/2015] [Accepted: 08/09/2015] [Indexed: 06/05/2023]
Abstract
Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d.
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Affiliation(s)
- Sikandar I Mulla
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 315800, China
| | - Anyi Hu
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 315800, China
| | - Yuwen Wang
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 315800, China
| | - Qian Sun
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 315800, China
| | - Shir-Ly Huang
- Department of Life Sciences, National Central University, No. 300 Chung-da Rd., Chung-li 32001, Taiwan, ROC.
| | - Han Wang
- College of Ecology and Resource Engineering, Wuyi University, Wuyishan City 354300, China
| | - Chang-Ping Yu
- Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China; Ningbo Urban Environment Observation and Research Station-NUEORS, Chinese Academy of Sciences, Ningbo 315800, China.
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Hand S, Wang B, Chu KH. Biodegradation of 1,4-dioxane: effects of enzyme inducers and trichloroethylene. THE SCIENCE OF THE TOTAL ENVIRONMENT 2015; 520:154-159. [PMID: 25813968 DOI: 10.1016/j.scitotenv.2015.03.031] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/28/2015] [Accepted: 03/08/2015] [Indexed: 06/04/2023]
Abstract
1,4-Dioxane is a groundwater contaminant and probable human carcinogen. In this study, two well-studied degradative bacteria Mycobacterium vaccae JOB5 and Rhodococcus jostii RHA1 were examined for their 1,4-dioxane degradation ability in the presence and absence of its co-contaminant, trichloroethylene (TCE), under different oxygenase-expression conditions. These two strains were precultured with R2A broth (complex nutrient medium) before supplementation with propane or 1-butanol to induce the expression of different oxygenases. Both propane- and 1-butanol-induced JOB5 and RHA1 were able to degrade 1,4-dioxane, TCE, and mixtures of 1,4-dioxane/TCE. Complete degradation of 1,4-dioxane/TCE mixture was observed only in propane-induced strain JOB5. Inhibition was observed between 1,4-dioxane and TCE for all cells. Furthermore, product toxicity caused incomplete degradation of 1,4-dioxane by 1-butanol-induced JOB5. In general, the more TCE degraded, the greater extent of product toxicity cells experienced; however, susceptibility to product toxicity was found to be both strain- and inducer-dependent. The findings of this study provide fundamental basis for developing an effective in-situ remediation method for 1,4-dioxane-contaminated ground water and the first known study of 1,4-dioxane degradation by wild-type strain RHA1.
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Affiliation(s)
- Steven Hand
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Baixin Wang
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Kung-Hui Chu
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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14
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Wang Y, Ogawa M, Fukuda K, Miyamoto H, Taniguchi H. Isolation and Identification of Mycobacteria from Soils at an Illegal Dumping Site and Landfills in Japan. Microbiol Immunol 2013; 50:513-24. [PMID: 16858142 DOI: 10.1111/j.1348-0421.2006.tb03821.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In order to study the diversity and community of genus Mycobacterium in polluted soils, we tried to isolate mycobacteria from 11 soil samples collected from an illegal dumping site and 3 landfills in Japan. Using culture methods with or without Acanthamoeba culbertsoni, a total of 19 isolates of mycobacteria were obtained from 5 soil samples and 3 of them were isolated only by the co-culture method with the amoeba. Conventional biochemical tests and sequencing of the hsp65, rpoB, and 16S rRNA genes were performed for species identification of 17 of the 19 isolates. Among the 17 isolates, there was one isolate each of Mycobacterium vanbaalenii, Mycobacterium mageritense, Mycobacterium frederiksbergense, M. vanbaalenii or Mycobacterium austroafricanum, and Mycobacterium chubuense or Mycobacterium chlorophenolicum. The remaining 12 isolates could not be precisely identified at the species level. A phylogenic tree based on the hsp65 sequences indicated that 2 of the 12 isolates were novel species. In addition, 4 isolates were phylogenically close to species that degrade polycyclic aromatic hydrocarbons, which induce some cancers in humans. These results demonstrated that there were many hitherto-unreported mycobacteria in the polluted soils, and suggested that some mycobacteria might play roles in the natural attenuation and engineered bioremediation of contaminated sites with other microorganisms.
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Affiliation(s)
- Yan Wang
- Department of Microbiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Fukuoka, Japan
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15
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Lee DG, Chu KH. Effects of growth substrate on triclosan biodegradation potential of oxygenase-expressing bacteria. CHEMOSPHERE 2013; 93:1904-1911. [PMID: 23890965 DOI: 10.1016/j.chemosphere.2013.06.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 06/10/2013] [Accepted: 06/24/2013] [Indexed: 06/02/2023]
Abstract
Triclosan is an antimicrobial agent, an endocrine disrupting compound, and an emerging contaminant in the environment. This is the first study investigating triclosan biodegradation potential of four oxygenase-expressing bacteria: Rhodococcus jostii RHA1, Mycobacterium vaccae JOB5, Rhodococcus ruber ENV425, and Burkholderia xenovorans LB400. B. xenovorans LB400 and R. ruber ENV425 were unable to degrade triclosan. Propane-grown M. vaccae JOB5 can completely degrade triclosan (5 mg L(-1)). R. jostii RHA1 grown on biphenyl, propane, and LB medium with dicyclopropylketone (DCPK), an alkane monooxygenase inducer, was able to degrade the added triclosan (5 mg L(-1)) to different extents. Incomplete degradation of triclosan by RHA1 is probably due to triclosan product toxicity. The highest triclosan transformation capacity (Tc, defined as the amount of triclosan degraded/the number of cells inactivated; 5.63×10(-3) ng triclosan/16S rRNA gene copies) was observed for biphenyl-grown RHA1 and the lowest Tc (0.20×10(-3) ng-triclosan/16S rRNA gene copies) was observed for propane-grown RHA1. No triclosan degradation metabolites were detected during triclosan degradation by propane- and LB+DCPK-grown RHA1. When using biphenyl-grown RHA1 for degradation, four chlorinated metabolites (2,4-dichlorophenol, monohydroxy-triclosan, dihydroxy-triclosan, and 2-chlorohydroquinone (a new triclosan metabolite)) were detected. Based on the detected metabolites, a meta-cleavage pathway was proposed for triclosan degradation.
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Affiliation(s)
- Do Gyun Lee
- Zachry Department of Civil Engineering, Texas A&M University, College Station, TX 77843-3136, USA
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16
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Matsen JB, Yang S, Stein LY, Beck D, Kalyuzhnaya MG. Global Molecular Analyses of Methane Metabolism in Methanotrophic Alphaproteobacterium, Methylosinus trichosporium OB3b. Part I: Transcriptomic Study. Front Microbiol 2013; 4:40. [PMID: 23565111 PMCID: PMC3615186 DOI: 10.3389/fmicb.2013.00040] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2013] [Accepted: 02/17/2013] [Indexed: 11/20/2022] Open
Abstract
Methane utilizing bacteria (methanotrophs) are important in both environmental and biotechnological applications, due to their ability to convert methane to multicarbon compounds. However, systems-level studies of methane metabolism have not been carried out in methanotrophs. In this work we have integrated genomic and transcriptomic information to provide an overview of central metabolic pathways for methane utilization in Methylosinus trichosporium OB3b, a model alphaproteobacterial methanotroph. Particulate methane monooxygenase, PQQ-dependent methanol dehydrogenase, the H4MPT-pathway, and NAD-dependent formate dehydrogenase are involved in methane oxidation to CO2. All genes essential for operation of the serine cycle, the ethylmalonyl-CoA (EMC) pathway, and the citric acid (TCA) cycle were expressed. PEP-pyruvate-oxaloacetate interconversions may have a function in regulation and balancing carbon between the serine cycle and the EMC pathway. A set of transaminases may contribute to carbon partitioning between the pathways. Metabolic pathways for acquisition and/or assimilation of nitrogen and iron are discussed.
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Affiliation(s)
- Janet B Matsen
- Department of Chemical Engineering, University of Washington Seattle, WA, USA
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17
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Kang JW, Khan Z, Doty SL. Biodegradation of trichloroethylene by an endophyte of hybrid poplar. Appl Environ Microbiol 2012; 78:3504-7. [PMID: 22367087 PMCID: PMC3346477 DOI: 10.1128/aem.06852-11] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 02/18/2012] [Indexed: 11/20/2022] Open
Abstract
We isolated and characterized a novel endophyte from hybrid poplar. This unique endophyte, identified as Enterobacter sp. strain PDN3, showed high tolerance to trichloroethylene (TCE). Without the addition of inducers, such as toluene or phenol, PDN3 rapidly reduced TCE levels in medium from 72.4 μM to 30.1 μM in 24 h with a concurrent release of 127 μM chloride ion, and nearly 80% of TCE (55.3 μM) was dechlorinated by PDN3 in 5 days with 166 μM chloride ion production, suggesting TCE degradation.
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Affiliation(s)
- Jun Won Kang
- School of Environmental and Forest Sciences, College of the Environment, University of Washington, Seattle, Washington, USA
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18
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Pieja AJ, Sundstrom ER, Criddle CS. Cyclic, alternating methane and nitrogen limitation increases PHB production in a methanotrophic community. BIORESOURCE TECHNOLOGY 2012; 107:385-392. [PMID: 22244897 DOI: 10.1016/j.biortech.2011.12.044] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Revised: 12/08/2011] [Accepted: 12/08/2011] [Indexed: 05/31/2023]
Abstract
To identify feast-famine strategies that favor PHB accumulation in Type II methanotrophic proteobacteria, three sequencing batch reactors seeded with a defined inoculum of Type II methanotrophs were subjected to 24-h cycles consisting of (1) repeated nitrogen limitation, (2) repeated nitrogen and oxygen limitation, and (3) repeated nitrogen and methane limitation. PHB levels within each reactor and capacity to produce PHB in offline batch incubations were monitored over 11 cycles. PHB content increased only in the reactor limited by both nitrogen and methane. This reactor became dominated by Methylocystis parvus OBBP with no detectable minority populations. It was concluded that repeated nitrogen and methane limitations favored PHB accumulation in strain OBBP and provided it with a competitive advantage under the conditions imposed.
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Affiliation(s)
- Allison J Pieja
- Environmental Engineering and Science, Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020, USA.
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19
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Ma J, Xu L, Jia L. Degradation of polycyclic aromatic hydrocarbons by Pseudomonas sp. JM2 isolated from active sewage sludge of chemical plant. J Environ Sci (China) 2012; 24:2141-8. [PMID: 23534211 DOI: 10.1016/s1001-0742(11)61064-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
It is important to screen strains that can decompose polycyclic aromatic hydrocarbons (PAHs) completely and rapidly with good adaptability for bioremediation in a local area. A bacterial strain JM2, which uses phenanthrene as its sole carbon source, was isolated from the active sewage sludge from a chemical plant in Jilin, China and identified as Pseudomonas based on 16S rDNA gene sequence analysis. Although the optimal growth conditions were determined to be pH 6.0 and 37 degrees C, JM2 showed a broad pH and temperature profile. At pH 4.5 and 9.3, JM2 could degrade more than 40% of fluorene and phenanthrene (50 mg/L each) within 4 days. In addition, when the temperature was as low as 4 degrees C, JM2 could degrade up to 24% fluorene and 12% phenanthrene. This showed the potential for JM2 to be applied in bioremediation over winter or in cold regions. Moreover, a nutrient augmentation study showed that adding formate into media could promote PAH degradation, while the supplement of salicylate had an inhibitive effect. Furthermore, in a metabolic pathway study, salicylate, phthalic acid, and 9-fluorenone were detected during the degradation of fluorene or phenanthrene. In conclusion, Pseudomonas sp. JM2 is a high performance strain in the degradation of fluorene and phenanthrene under extreme pH and temperature conditions. It might be useful in the bioremediation of PAHs.
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Affiliation(s)
- Jing Ma
- School of Life Science and Biotechnology, Dalian University of Technology, Liaoning 116023, China.
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20
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Pfluger AR, Wu WM, Pieja AJ, Wan J, Rostkowski KH, Criddle CS. Selection of Type I and Type II methanotrophic proteobacteria in a fluidized bed reactor under non-sterile conditions. BIORESOURCE TECHNOLOGY 2011; 102:9919-9926. [PMID: 21906939 DOI: 10.1016/j.biortech.2011.08.054] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2011] [Revised: 08/11/2011] [Accepted: 08/12/2011] [Indexed: 05/31/2023]
Abstract
Type II methanotrophs produce polyhydroxybutyrate (PHB), while Type I methanotrophs do not. A laboratory-scale fluidized bed reactor was initially inoculated with a Type II Methylocystis-like dominated culture. At elevated levels of dissolved oxygen (DO, 9 mg/L), pH of 6.2-6.5 with nitrate as the N-source, a Methylobacter-like Type I methanotroph became dominant within the biofilms which did not produce PHB. A shift to biofilms capable of PHB production was achieved by re-inoculating with Type II Methylosinus culture, providing dissolved N(2) as the N-source, and maintaining a low influent DO (2.0mg/L). The resulting biofilms contained both Types I and II methanotrophs. Batch tests indicated that biofilm samples grown with N(2) became dominated by Type II methanotrophs and produced PHB. Enrichments with nitrate or ammonium were dominated by Type I methanotrophs without PHB production capability. The key selection factors favoring Type II were N(2) as N-source and low DO.
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Affiliation(s)
- Andrew R Pfluger
- Department of Geography and Environmental Engineering, United States Military Academy, 745 Brewerton Road, West Point, NY 10996-1602, USA
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21
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Pieja AJ, Sundstrom ER, Criddle CS. Poly-3-hydroxybutyrate metabolism in the type II methanotroph Methylocystis parvus OBBP. Appl Environ Microbiol 2011; 77:6012-9. [PMID: 21724874 PMCID: PMC3165381 DOI: 10.1128/aem.00509-11] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Accepted: 06/25/2011] [Indexed: 11/20/2022] Open
Abstract
Differences in carbon assimilation pathways and reducing power requirements among organisms are likely to affect the role of the storage polymer poly-3-hydroxybutyrate (PHB). Previous researchers have demonstrated that PHB functions as a sole growth substrate in aerobic cultures enriched on acetate during periods of carbon deficiency, but it is uncertain how C(1) metabolism affects the role of PHB. In the present study, the type II methanotroph Methylocystis parvus OBBP did not replicate using stored PHB in the absence of methane, even when all other nutrients were provided in excess. When PHB-rich cultures of M. parvus OBBP were deprived of carbon and nitrogen for 48 h, they did not utilize significant amounts of stored PHB, and neither cell concentrations nor concentrations of total suspended solids changed significantly. When methane and nitrogen both were present, PHB and methane were consumed simultaneously. Cells with PHB had significantly higher specific growth rates than cells lacking PHB. The addition of formate (a source of reducing power) to PHB-rich cells delayed PHB consumption, but the addition of glyoxylate (a source of C(2) units) did not. This and results from other researchers suggest that methanotrophic PHB metabolism is linked to the supply of reducing power as opposed to the supply of C(2) units for synthesis.
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Affiliation(s)
- Allison J. Pieja
- Environmental Engineering and Science, Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305
| | - Eric R. Sundstrom
- Environmental Engineering and Science, Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305
| | - Craig S. Criddle
- Environmental Engineering and Science, Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305
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22
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Proteomic and targeted qPCR analyses of subsurface microbial communities for presence of methane monooxygenase. Biodegradation 2011; 22:1045-59. [DOI: 10.1007/s10532-011-9462-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/17/2011] [Indexed: 01/21/2023]
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23
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Paraffin oil as a “methane vector” for rapid and high cell density cultivation of Methylosinus trichosporium OB3b. Appl Microbiol Biotechnol 2009; 83:669-77. [DOI: 10.1007/s00253-009-1866-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Revised: 12/17/2008] [Accepted: 01/09/2009] [Indexed: 11/27/2022]
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24
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The Methane Monooxygenase Intrinsic Activity of Kinds of Methanotrophs. Appl Biochem Biotechnol 2008; 157:431-41. [DOI: 10.1007/s12010-008-8447-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Accepted: 11/18/2008] [Indexed: 10/21/2022]
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25
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Trichloroethylene cometabolic degradation by Rhodococcus sp. L4 induced with plant essential oils. Biodegradation 2008; 20:281-91. [DOI: 10.1007/s10532-008-9220-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Accepted: 09/09/2008] [Indexed: 10/21/2022]
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26
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Halsey KH, Sayavedra-Soto LA, Bottomley PJ, Arp DJ. Trichloroethylene degradation by butane-oxidizing bacteria causes a spectrum of toxic effects. Appl Microbiol Biotechnol 2005; 68:794-801. [PMID: 15754184 DOI: 10.1007/s00253-005-1944-z] [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] [Received: 01/04/2005] [Revised: 02/08/2005] [Accepted: 02/13/2005] [Indexed: 10/25/2022]
Abstract
The physiological consequences of trichloroethylene (TCE) transformation by three butane oxidizers were examined. Pseudomonas butanovora, Mycobacterium vaccae, and Nocardioides sp. CF8 utilize distinctly different butane monooxygenases (BMOs) to initiate degradation of the recalcitrant TCE molecule. Although the primary toxic event resulting from TCE cometabolism by these three strains was loss of BMO activity, species differences were observed. P. butanovora and Nocardioides sp. CF8 maintained only 4% residual BMO activity following exposure to 165 microM TCE for 90 min and 180 min, respectively. In contrast, M. vaccae maintained 34% residual activity even after exposure to 165 microM TCE for 300 min. Culture viability was reduced 83% in P. butanovora, but was unaffected in the other two species. Transformation of 530 nmol of TCE by P. butanovora (1.0 mg total protein) did not affect the viability of BMO-deficient P. butanovora cells, whereas transformation of 482 nmol of TCE by toluene-grown Burkholderia cepacia G4 caused 87% of BMO-deficient P. butanovora cells to lose viability. Together, these results contrast with those previously reported for other bacteria carrying out TCE cometabolism and demonstrate the range of cellular toxicities associated with TCE cometabolism.
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Affiliation(s)
- Kimberly H Halsey
- Molecular and Cellular Biology Program, Oregon State University, ALS 3021, Corvallis, OR 97331-2902, USA
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27
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Chen HJ, Tseng DH, Huang SL. Biodegradation of octylphenol polyethoxylate surfactant Triton X-100 by selected microorganisms. BIORESOURCE TECHNOLOGY 2005; 96:1483-91. [PMID: 15939276 DOI: 10.1016/j.biortech.2004.11.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2003] [Revised: 11/10/2004] [Accepted: 11/21/2004] [Indexed: 05/02/2023]
Abstract
Octylphenol polyethoxylate (OPEO(n)) surfactants are used in numerous commercial and industrial products. Large amounts of such surfactants and their various residual biodegradation by-products are ultimately released into the environment. OPEO(n) biodegradation was performed in this study using pure cultures of Pseudomonas species and strains under different environmental conditions. Environmental factors including the pH, nitrogen sources, and growth kinetics of the cells were investigated. The intermediates of Triton X-100 biotransformation were detected by high performance liquid chromatography-mass spectrophotograph (HPLC-MS). We found the highest specific growth rate (mu) was 0.56 h(-1) and this was achieved by strain E with an initial concentration of Triton X-100 of 5000 mg L(-1). A pH level of 7 was most favorable for cell growth for all five strains. The highest specific growth rate was achieved using (NH(4))(2)SO(4) as the sole nitrogen source for strain E. Strain A showed an enhancement of growth when between 0.2 and 1.4 mg L(-1) of H(2)O(2) was added. Detection of intermediates was possible after four days of transformation and the octylphenol triethoxylate (OPEO(3)) peak was predominant, while the high molecular weight peaks had all disappeared. The kinetic analysis demonstrated that the greatest maximum specific growth rate (mu(max)) and the greatest saturation constant (K(s)) of 0.83 h(-1) and 5.24 mg L(-1), respectively, were obtained for strain E in 5000 mg L(-1) Triton X-100. The higher K(i) revealed that strain A was resistant to higher Triton X-100 concentrations.
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Affiliation(s)
- Hsi-Jien Chen
- Department of Environmental Engineering, Lan-Yang Institute of Technology, Tou-cheng, Taiwan, ROC
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28
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Krug EC, Winstanley D. The need for comprehensive and consistent treatment of the nitrogen cycle in nitrogen cycling and mass balance studies: I. Terrestrial nitrogen cycle. THE SCIENCE OF THE TOTAL ENVIRONMENT 2002; 293:1-29. [PMID: 12109464 DOI: 10.1016/s0048-9697(01)01133-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A review of conceptual models that scientists use to characterize the nitrogen (N) cycle and to conduct N mass balance studies at global, regional and local scales is presented. Large uncertainties in processes and process rates make it difficult to conduct precise N mass balances and the dominant conceptual model has changed in recent decades. An earlier conceptual model recognized explicitly that human activities, especially agriculture, have both depleted terrestrial N and increased the fixation of atmospheric N in biologically available forms. The current conceptual model does not include adequate treatment of the depletion of the terrestrial N reservoir, the resulting transfer of N to the hydrosphere and atmosphere, or the cycling of terrestrial N below the plow layer. Thus, it delivers an unrealistically limited view of human influences on the N cycle. It is recommended that a comprehensive and consistent treatment of terrestrial N cycling be developed to better facilitate scientific explanation of historical N-related environmental changes and more closely balance N budgets on a range of geographical and temporal scales. Improved N-cycle models will provide an improved scientific basis for answering important resource management and policy questions.
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Affiliation(s)
- E C Krug
- Illinois State Water Survey, Champaign 61820, USA.
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29
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Chu KH, Alvarez-Cohen L. Evaluation of toxic effects of aeration and trichloroethylene oxidation on methanotrophic bacteria grown with different nitrogen sources. Appl Environ Microbiol 1999; 65:766-72. [PMID: 9925614 PMCID: PMC91093 DOI: 10.1128/aem.65.2.766-772.1999] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this study we evaluated specific and nonspecific toxic effects of aeration and trichloroethylene (TCE) oxidation on methanotrophic bacteria grown with different nitrogen sources (nitrate, ammonia, and molecular nitrogen). The specific toxic effects, exerted directly on soluble methane monooxygenase (sMMO), were evaluated by comparing changes in methane uptake rates and naphthalene oxidation rates following aeration and/or TCE oxidation. Nonspecific toxic effects, defined as general cellular damage, were examined by using a combination of epifluorescent cellular stains to measure viable cell numbers based on respiratory activity and measuring formate oxidation activities following aeration and TCE transformation. Our results suggest that aeration damages predominantly sMMO rather than other general cellular components, whereas TCE oxidation exerts a broad range of toxic effects that damage both specific and nonspecific cellular functions. TCE oxidation caused sMMO-catalyzed activity and respiratory activity to decrease linearly with the amount of substrate degraded. Severe TCE oxidation toxicity resulted in total cessation of the methane, naphthalene, and formate oxidation activities and a 95% decrease in the respiratory activity of methanotrophs. The failure of cells to recover even after 7 days of incubation with methane suggests that cellular recovery following severe TCE product toxicity is not always possible. Our evidence suggests that generation of greater amounts of sMMO per cell due to nitrogen fixation may be responsible for enhanced TCE oxidation activities of nitrogen-fixing methanotrophs rather than enzymatic protection mechanisms associated with the nitrogenase enzymes.
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Affiliation(s)
- K H Chu
- Department of Civil and Environmental Engineering, University of California, Berkeley, California 94720-1710, USA
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