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Gunasekaran V, Canela N, Constantí M. Comparative Proteomic Analysis of an Ethyl Tert-Butyl Ether-Degrading Bacterial Consortium. Microorganisms 2022; 10:microorganisms10122331. [PMID: 36557584 PMCID: PMC9781318 DOI: 10.3390/microorganisms10122331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/29/2022] Open
Abstract
A bacterial consortium capable of degrading ethyl tert-butyl ether (ETBE) as a sole carbon source was enriched and isolated from gasoline-contaminated water. Arthrobacter sp., Herbaspirillum sp., Pseudacidovorax sp., Pseudomonas sp., and Xanthomonas sp. were identified as the initial populations with the 16S rDNA analysis. The consortium aerobically degraded 49% of 50 mg/L of ETBE, in 6 days. The ETBE degrading efficiency of the consortium increased to 98% even with the higher concentrations of ETBE (1000 mg/L) in the subsequent subcultures, which accumulated tert-butyl alcohol (TBA). Xanthomonas sp. and Pseudomonas sp. were identified as the predominant ETBE degrading populations in the final subculture. The metaproteome of the ETBE-grown bacterial consortium was compared with the glucose-grown bacterial consortium, using 2D-DIGE. Proteins related to the ETBE metabolism, stress response, carbon metabolism and chaperones were found to be abundant in the presence of ETBE while proteins related to cell division were less abundant. The metaproteomic study revealed that the ETBE does have an effect on the metabolism of the bacterial consortium. It also enabled us to understand the responses of the complex bacterial consortium to ETBE, thus revealing interesting facts about the ETBE degrading bacterial community.
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Affiliation(s)
- Vijayalakshmi Gunasekaran
- Departament d’Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans, 26, 43007 Tarragona, Spain
- FA Bio, Harpenden AL5 2JQ, UK
- Correspondence: (V.G.); (M.C.); Tel.: +34-977-558457 (M.C.)
| | - Núria Canela
- Centre for Omic Sciences (COS), Joint Unit Universitat Rovira i Virgili-EURECAT, Av. Universitat 1, 43204 Reus, Spain
| | - Magda Constantí
- Departament d’Enginyeria Química, Universitat Rovira i Virgili, Av. Països Catalans, 26, 43007 Tarragona, Spain
- Correspondence: (V.G.); (M.C.); Tel.: +34-977-558457 (M.C.)
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Adlan NA, Sabri S, Masomian M, Ali MSM, Rahman RNZRA. Microbial Biodegradation of Paraffin Wax in Malaysian Crude Oil Mediated by Degradative Enzymes. Front Microbiol 2020; 11:565608. [PMID: 33013795 PMCID: PMC7506063 DOI: 10.3389/fmicb.2020.565608] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 08/13/2020] [Indexed: 11/26/2022] Open
Abstract
The deposition of paraffin wax in crude oil is a problem faced by the oil and gas industry during extraction, transportation, and refining of crude oil. Most of the commercialized chemical additives to prevent wax are expensive and toxic. As an environmentally friendly alternative, this study aims to find a novel thermophilic bacterial strain capable of degrading paraffin wax in crude oil to control wax deposition. To achieve this, the biodegradation of crude oil paraffin wax by 11 bacteria isolated from seawater and oil-contaminated soil samples was investigated at 70°C. The bacteria were identified as Geobacillus kaustophilus N3A7, NFA23, DFY1, Geobacillus jurassicus MK7, Geobacillus thermocatenulatus T7, Parageobacillus caldoxylosilyticus DFY3 and AZ72, Anoxybacillus geothermalis D9, Geobacillus stearothermophilus SA36, AD11, and AD24. The GCMS analysis showed that strains N3A7, MK7, DFY1, AD11, and AD24 achieved more than 70% biodegradation efficiency of crude oil in a short period (3 days). Notably, most of the strains could completely degrade C37–C40 and increase the ratio of C14–C18, especially during the initial 2 days incubation. In addition, the degradation of crude oil also resulted in changes in the pH of the medium. The degradation of crude oil is associated with the production of degradative enzymes such as alkane monooxygenase, alcohol dehydrogenase, lipase, and esterase. Among the 11 strains, the highest activities of alkane monooxygenase were recorded in strain AD24. A comparatively higher overall alcohol dehydrogenase, lipase, and esterase activities were observed in strains N3A7, MK7, DFY1, AD11, and AD24. Thus, there is a potential to use these strains in oil reservoirs, crude oil processing, and recovery to control wax deposition. Their ability to withstand high temperature and produce degradative enzymes for long-chain hydrocarbon degradation led to an increase in the short-chain hydrocarbon ratio, and subsequently, improving the quality of the oil.
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Affiliation(s)
- Nur Aina Adlan
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Suriana Sabri
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Malihe Masomian
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Centre for Virus and Vaccine Research, School of Science and Technology, Sunway University, Bandar Sunway, Malaysia
| | - Mohd Shukuri Mohamad Ali
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
| | - Raja Noor Zaliha Raja Abd Rahman
- Enzyme and Microbial Technology Research Centre, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia.,Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang, Malaysia
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Chandra P, Enespa, Singh R, Arora PK. Microbial lipases and their industrial applications: a comprehensive review. Microb Cell Fact 2020; 19:169. [PMID: 32847584 PMCID: PMC7449042 DOI: 10.1186/s12934-020-01428-8] [Citation(s) in RCA: 265] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022] Open
Abstract
Lipases are very versatile enzymes, and produced the attention of the several industrial processes. Lipase can be achieved from several sources, animal, vegetable, and microbiological. The uses of microbial lipase market is estimated to be USD 425.0 Million in 2018 and it is projected to reach USD 590.2 Million by 2023, growing at a CAGR of 6.8% from 2018. Microbial lipases (EC 3.1.1.3) catalyze the hydrolysis of long chain triglycerides. The microbial origins of lipase enzymes are logically dynamic and proficient also have an extensive range of industrial uses with the manufacturing of altered molecules. The unique lipase (triacylglycerol acyl hydrolase) enzymes catalyzed the hydrolysis, esterification and alcoholysis reactions. Immobilization has made the use of microbial lipases accomplish its best performance and hence suitable for several reactions and need to enhance aroma to the immobilization processes. Immobilized enzymes depend on the immobilization technique and the carrier type. The choice of the carrier concerns usually the biocompatibility, chemical and thermal stability, and insolubility under reaction conditions, capability of easy rejuvenation and reusability, as well as cost proficiency. Bacillus spp., Achromobacter spp., Alcaligenes spp., Arthrobacter spp., Pseudomonos spp., of bacteria and Penicillium spp., Fusarium spp., Aspergillus spp., of fungi are screened large scale for lipase production. Lipases as multipurpose biological catalyst has given a favorable vision in meeting the needs for several industries such as biodiesel, foods and drinks, leather, textile, detergents, pharmaceuticals and medicals. This review represents a discussion on microbial sources of lipases, immobilization methods increased productivity at market profitability and reduce logistical liability on the environment and user.
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Affiliation(s)
- Prem Chandra
- Food Microbiology & Toxicology, Department of Microbiology, School for Biomedical and Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University (A Central) University, Lucknow, Uttar Pradesh 226025 India
| | - Enespa
- Department of Plant Pathology, School for Agriculture, SMPDC, University of Lucknow, Lucknow, 226007 U.P. India
| | - Ranjan Singh
- Department of Environmental Science, School for Environmental Science, Babasaheb Bhimrao Ambedkar University (A Central) University, Lucknow, U.P. India
| | - Pankaj Kumar Arora
- Department of Microbiology, School for Biomedical and Pharmaceutical Sciences, Babasaheb Bhimrao Ambedkar University (A Central) University, Lucknow, U.P. India
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Biodegradation of Methyl Tertiary Butyl Ether (MTBE) by a Microbial Consortium in a Continuous Up-Flow Packed-Bed Biofilm Reactor: Kinetic Study, Metabolite Identification and Toxicity Bioassays. PLoS One 2016; 11:e0167494. [PMID: 27907122 PMCID: PMC5132332 DOI: 10.1371/journal.pone.0167494] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 11/15/2016] [Indexed: 02/01/2023] Open
Abstract
This study investigated the aerobic biodegradation of methyl tertiary-butyl ether (MTBE) by a microbial consortium in a continuous up-flow packed-bed biofilm reactor using tezontle stone particles as a supporting material for the biofilm. Although MTBE is toxic for microbial communities, the microbial consortium used here was able to resist MTBE loading rates up to 128.3 mg L-1 h-1, with removal efficiencies of MTBE and chemical oxygen demand (COD) higher than 90%. A linear relationship was observed between the MTBE loading rate and the MTBE removal rate, as well as between the COD loading rate and the COD removal rate, within the interval of MTBE loading rates from 11.98 to 183.71 mg L-1 h-1. The metabolic intermediate tertiary butyl alcohol (TBA) was not detected in the effluent during all reactor runs, and the intermediate 2-hydroxy butyric acid (2-HIBA) was only detected at MTBE loading rates higher than 128.3 mg L-1 h-1. The results of toxicity bioassays with organisms from two different trophic levels revealed that the toxicity of the influent was significantly reduced after treatment in the packed-bed reactor. The packed-bed reactor system used in this study was highly effective for the continuous biodegradation of MTBE and is therefore a promising alternative for detoxifying MTBE-laden wastewater and groundwater.
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Alfonso-Gordillo G, Cristiani-Urbina E, Flores-Ortiz CM, Peralta H, Cancino-Díaz JC, Cruz-Maya JA, Jan-Roblero J. Stenotrophomonas maltophilia isolated from gasoline-contaminated soil is capable of degrading methyl tert-butyl ether. ELECTRON J BIOTECHN 2016. [DOI: 10.1016/j.ejbt.2016.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Key KC, Sublette KL, Duncan K, Mackay DM, Scow KM, Ogles D. Using DNA-Stable Isotope Probing to Identify MTBE- and TBA-Degrading Microorganisms in Contaminated Groundwater. GROUND WATER MONITORING & REMEDIATION 2013; 33:57-68. [PMID: 25525320 PMCID: PMC4267322 DOI: 10.1111/gwmr.12031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Although the anaerobic biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) has been documented in the laboratory and the field, knowledge of the microorganisms and mechanisms involved is still lacking. In this study, DNA-stable isotope probing (SIP) was used to identify microorganisms involved in anaerobic fuel oxygenate biodegradation in a sulfate-reducing MTBE and TBA plume. Microorganisms were collected in the field using Bio-Sep® beads amended with 13C5-MTBE, 13C1-MTBE (only methoxy carbon labeled), or13C4-TBA. 13C-DNA and 12C-DNA extracted from the Bio-Sep beads were cloned and 16S rRNA gene sequences were used to identify the indigenous microorganisms involved in degrading the methoxy group of MTBE and the tert-butyl group of MTBE and TBA. Results indicated that microorganisms were actively degrading 13C-labeled MTBE and TBA in situ and the 13C was incorporated into their DNA. Several sequences related to known MTBE- and TBA-degraders in the Burkholderiales and the Sphingomonadales orders were detected in all three13C clone libraries and were likely to be primary degraders at the site. Sequences related to sulfate-reducing bacteria and iron-reducers, such as Geobacter and Geothrix, were only detected in the clone libraries where MTBE and TBA were fully labeled with 13C, suggesting that they were involved in processing carbon from the tert-butyl group. Sequences similar to the Pseudomonas genus predominated in the clone library where only the methoxy carbon of MTBE was labeled with 13C. It is likely that members of this genus were secondary degraders cross-feeding on 13C-labeled metabolites such as acetate.
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Affiliation(s)
- Katherine C. Key
- Department of Chemical Engineering, University of Tulsa, Tulsa, OK, USA
| | - Kerry L. Sublette
- Department of Chemical Engineering, University of Tulsa, Tulsa, OK, USA
| | - Kathleen Duncan
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK
| | - Douglas M. Mackay
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA
| | - Kate M. Scow
- Department of Land, Air, and Water Resources, University of California at Davis, Davis, CA
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Anaerobic methyl tert-butyl ether-degrading microorganisms identified in wastewater treatment plant samples by stable isotope probing. Appl Environ Microbiol 2012; 78:2973-80. [PMID: 22327600 DOI: 10.1128/aem.07253-11] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Anaerobic methyl tert-butyl ether (MTBE) degradation potential was investigated in samples from a range of sources. From these 22 experimental variations, only one source (from wastewater treatment plant samples) exhibited MTBE degradation. These microcosms were methanogenic and were subjected to DNA-based stable isotope probing (SIP) targeted to both bacteria and archaea to identify the putative MTBE degraders. For this purpose, DNA was extracted at two time points, subjected to ultracentrifugation, fractioning, and terminal restriction fragment length polymorphism (TRFLP). In addition, bacterial and archaeal 16S rRNA gene clone libraries were constructed. The SIP experiments indicated bacteria in the phyla Firmicutes (family Ruminococcaceae) and Alphaproteobacteria (genus Sphingopyxis) were the dominant MTBE degraders. Previous studies have suggested a role for Firmicutes in anaerobic MTBE degradation; however, the putative MTBE-degrading microorganism in the current study is a novel MTBE-degrading phylotype within this phylum. Two archaeal phylotypes (genera Methanosarcina and Methanocorpusculum) were also enriched in the heavy fractions, and these organisms may be responsible for minor amounts of MTBE degradation or for the uptake of metabolites released from the primary MTBE degraders. Currently, limited information exists on the microorganisms able to degrade MTBE under anaerobic conditions. This work represents the first application of DNA-based SIP to identify anaerobic MTBE-degrading microorganisms in laboratory microcosms and therefore provides a valuable set of data to definitively link identity with anaerobic MTBE degradation.
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Latorre I, Hwang S, Montalvo-Rodriguez R. Isolation and molecular identification of landfill bacteria capable of growing on di-(2-ethylhexyl) phthalate and deteriorating PVC materials. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2012; 47:2254-2262. [PMID: 22934997 PMCID: PMC3432978 DOI: 10.1080/10934529.2012.707549] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Waste materials containing Di-(2-ethylhexyl) phthalate (DEHP), a suspected endocrine disruptor and reasonably anticipated human carcinogen, are typically disposed of in landfills. Despite this, very few studies had been conducted to isolate and identify DEHP-degrading bacteria in landfill leachate. Therefore, this study was conducted to isolate and characterize bacteria in landfill leachate growing on DEHP as the sole carbon source and deteriorating PVC materials. Four strains LHM1, LHM2, LHM3 and LHM4, not previously reported as DEHP-degraders, were identified via 16S rRNA gene sequence. Gram-positive strains LHM1 and LHM2 had a greater than 97% similarity with Chryseomicrobium imtechense MW 10(T) and Lysinibacillus fusiformis NBRC 15717(T), respectively. Gram-negative strains LHM3 and LHM4 were related to Acinetobacter calcoaceticus DSM 30006(T) (90.7% similarity) and Stenotrophomonas pavanii ICB 89(T) (96.0% similarity), respectively. Phylogenetic analysis also corroborated these similarities of strains LHM1 and LHM2 to the corresponding bacteria species. Strains LHM2 and LHM4 grew faster than strains LHM1 and LHM3 in the enrichment where DEHP was the sole carbon source. When augmented to the reactors with PVC shower curtains containing DEHP, strains LHM1 and LHM2 developed greater optical densities in the solution phase and thicker biofilm on the surfaces of the shower curtains.
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Affiliation(s)
- Isomar Latorre
- Department of Civil Engineering, University of Puerto Rico, Mayaguez, PR 00681
| | - Sangchul Hwang
- Department of Civil Engineering, University of Puerto Rico, Mayaguez, PR 00681
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Kao CM, Chen CS, Tsa FY, Yang KH, Chien CC, Liang SH, Yang CA, Chen SC. Application of real-time PCR, DGGE fingerprinting, and culture-based method to evaluate the effectiveness of intrinsic bioremediation on the control of petroleum-hydrocarbon plume. JOURNAL OF HAZARDOUS MATERIALS 2010; 178:409-416. [PMID: 20185233 DOI: 10.1016/j.jhazmat.2010.01.096] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Revised: 01/16/2010] [Accepted: 01/19/2010] [Indexed: 05/28/2023]
Abstract
Real-time polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE), and the culture-based method were applied in the intrinsic bioremediation study at a petroleum-hydrocarbon contaminated site. The genes of phenol hydroxylase (PHE), ring-hydroxylating toluene monooxygenase (RMO), naphthalene dioxygenase (NAH), toluene monooxygenase (TOL), toluene dioxygenase (TOD), and biphenyl dioxygenase (BPH4) were quantified by real-time PCR. Results show that PHE gene was detected in groundwater contaminated with benzene, toluene, ethylbenzene, xylene isomers (BTEX) and methyl tert-butyl ether (MTBE), and this indicates that intrinsic bioremediation occurred at this contaminated site. Results from DGGE analyses reveal that the petroleum-hydrocarbon plume caused the variation in microbial communities. In this study, MTBE degraders including Pseudomonas sp. NKNU01, Bacillus sp. NKNU01, Klebsiella sp. NKNU01, Enterobacter sp. NKNU01, and Enterobacter sp. NKNU02 were isolated from the contaminated groundwater using the cultured-based method. Results from MTBE biodegradation experiment show that the isolated bacteria were affected by propane. This indicates that propane may influence the metabolic pathway of MTBE by these bacteria. Knowledge and comprehension obtained from this study will be helpful in evaluating the occurrence and effectiveness of intrinsic bioremediation on the remediation of petroleum-hydrocarbon contaminated groundwater.
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Affiliation(s)
- Chih-Ming Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
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Mukred AM, Hamid AA, Hamzah A, Yusoff WMW. Enhancement of biodegradation of crude petroleum-oil in contaminated water by the addition of nitrogen sources. Pak J Biol Sci 2008; 11:2122-2127. [PMID: 19266926 DOI: 10.3923/pjbs.2008.2122.2127] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Addition of nitrogen sources as supplementary nutrient into MSM medium to enhance biodegradation by stimulating the growth four isolates, Acinetobacter faecalis, Staphylococcus sp., Pseudomonas putida and Neisseria elongata isolated from petroleum contaminated groundwater, wastewater aeration pond and biopond at the oil refinery Terengganu Malaysia was investigated. The organic nitrogen sources tested not only supported growth but also enhances biodegradation of 1% Tapis crude oil. All four isolates showed good growth especially when peptone was employed as the organic nitrogen compared to growth in the basal medium. Gas chromatography showed that more then 91, 93, 94 and 95% degradation of total hydrocarbon was observed after 5 days of incubation by isolates Pseudomonas putida, Neisseria elongate, Acinetobacter faecalis and Staphylococcus sp., respectively.
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Affiliation(s)
- A M Mukred
- School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
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Okeke BC. Bioremoval of hexavalent chromium from water by a salt tolerant bacterium, Exiguobacterium sp. GS1. J Ind Microbiol Biotechnol 2008; 35:1571-9. [DOI: 10.1007/s10295-008-0399-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2007] [Accepted: 07/07/2008] [Indexed: 11/29/2022]
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Müller RH, Rohwerder T, Harms H. Degradation of fuel oxygenates and their main intermediates by Aquincola tertiaricarbonis L108. MICROBIOLOGY-SGM 2008; 154:1414-1421. [PMID: 18451050 DOI: 10.1099/mic.0.2007/014159-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Growth of Aquincola tertiaricarbonis L108 on the fuel oxygenates methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME), as well as on their main metabolites tert-butyl alcohol (TBA), tert-amyl alcohol (TAA) and 2-hydroxyisobutyrate (2-HIBA) was systematically investigated to characterize the range and rates of oxygenate degradation by this strain. The effective maximum growth rates for MTBE, ETBE and TAME at pH 7 and 30 degrees C were 0.045 h(-1), 0.06 h(-1) and 0.055 h(-1), respectively, whereas TAA, TBA and 2-HIBA permitted growth at rates up to 0.08 h(-1), 0.1 h(-1) and 0.17 h(-1), respectively. The experimental growth yields with all these substrates were high. Yields of 0.55 g dry mass (dm) (g MTBE)(-1), 0.53 g dm (g ETBE)(-1), 0.81 g dm (g TAME)(-1), 0.48 g dm (g TBA)(-1), 0.76 g dm (g TAA)(-1) and 0.54 g dm (g 2-HIBA)(-1) were obtained. Maximum specific degradation rates were 0.92 mmol MTBE h(-1) (g dm)(-1), 1.11 mmol ETBE h(-1) g(-1), 0.66 mmol TAME h(-1) g(-1), 1.19 mmol TAA h(-1) g(-1), 2.82 mmol TBA h(-1) g(-1), and 3.27 mmol 2-HIBA h(-1) g(-1). The relatively high rates with TBA, TAA and 2-HIBA indicate that the transformations of these metabolites did not limit the metabolism of MTBE and the related ether compounds. Despite the fact that these metabolites still carry a tertiary carbon atom that is commonly suspected to confer recalcitrance to the ether oxygenates, the transformation rates were in the same range as those with succinate and fructose. With MTBE, strain L108 grew at pHs between 5.5 and 8.0 at near-maximal rate, whereas no growth was found below pH 5.0 and above pH 9.0. The optimum growth temperature was 30 degrees C, but at 5 degrees C still about 15 % of the maximum rate remained, whereas no growth occurred at 42 degrees C. This indicates that MTBE metabolites are valuable substrates and that A. tertiaricarbonis L108 is a good candidate for bioremediation purposes. The possible origin of its exceptional metabolic capability is discussed in terms of the evolution of enzymic activities involved in the conversion of compounds carrying tertiary butyl groups.
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Affiliation(s)
- Roland H Müller
- UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, D-04318 Leipzig, Germany
| | - Thore Rohwerder
- Aquatic Biotechnology, Biofilm Centre, University Duisburg-Essen, Geibelstr. 41, D-47057 Duisburg, Germany
| | - Hauke Harms
- UFZ, Helmholtz Centre for Environmental Research, Department of Environmental Microbiology, Permoserstr. 15, D-04318 Leipzig, Germany
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Biodegradation of methyl tert-butyl ether as a sole carbon source by aerobic granules cultivated in a sequencing batch reactor. Bioprocess Biosyst Eng 2008; 31:527-34. [DOI: 10.1007/s00449-007-0193-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2007] [Accepted: 12/20/2007] [Indexed: 10/22/2022]
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14
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Okeke BC, Laymon J, Crenshaw S, Oji C. Environmental and kinetic parameters for Cr(VI) bioreduction by a bacterial monoculture purified from Cr(VI)-resistant consortium. Biol Trace Elem Res 2008; 123:229-41. [PMID: 18317706 DOI: 10.1007/s12011-008-8098-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Accepted: 01/21/2008] [Indexed: 10/22/2022]
Abstract
Hexavalent chromium, Cr(VI), is toxic to living systems. Widespread contamination of water and soil by Cr(VI) present a serious public health problem. Chromium-resistant bacteria can reduce and detoxify Cr(VI). Twelve bacteria resistant to high concentrations of Cr(VI) were isolated from soil enrichment cultures. Environmental parameters and kinetic parameters of Cr(VI) bioreduction by one monoculture isolate, identified by 16S rRNA gene sequence as Bacillus sp. PB2, were studied. The optimal temperature for growth and Cr(VI) reduction was 35 degrees C. The isolate grew luxuriantly and substantially reduced Cr(VI) at initial pH 7.5 to 9. Maximal Cr(VI) bioreduction occurred at initial pH 8.0. Substantial Cr(VI) bioreduction was observed in salt media, but removal efficiency was inversely related to salt concentration (1-9%). Michaelis-Menten hyperbolic equation and the Lineweaver-Burk double reciprocal plot were comparatively employed to determine the k (m) and V (max) of Cr(VI) bioreduction. A k (m) of 82.5 microg mL(-1) and V (max) of 7.78 microg mL(-1) h(-1) were calculated by nonlinear regression analysis of the hyperbola curve. Linear regression analysis of the double reciprocal plot revealed k (m) and V (max) of 80.9 microg mL(-1) and 10.6 microg mL(-1) h(-1), respectively. Time course studies displayed about 90% reduction of Cr(VI) at an initial concentration of 8,000 microg L(-1) in 8 h, with an estimated t (1/2) of 4 h. Data from time course analysis of the rate of Cr(VI) bioreduction fitted zero-order model, and the kinetic constant k was calculated to be 840 microg L(-1) h(-1). The monoculture isolate, Bacillus sp. PB2, strongly reduces Cr(VI) and could be used for bioremediation of Cr(VI)-contaminated aquatic and terrestrial environments.
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Affiliation(s)
- Benedict C Okeke
- Department of Biology, Auburn University Montgomery, P.0. Box 244023, Montgomery, AL, 36124, USA.
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