Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres

Handle URI:
http://hdl.handle.net/10754/610579
Title:
Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres
Authors:
Gonzalez-Gil, Graciela; Lens, Piet N. L.; Saikaly, Pascal ( 0000-0001-7678-3986 )
Abstract:
Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.
KAUST Department:
Biological and Environmental Sciences and Engineering (BESE) Division; Water Desalination & Reuse Research Cntr
Citation:
Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres 2016, 7 Frontiers in Microbiology
Publisher:
Frontiers Media SA
Journal:
Frontiers in Microbiology
Issue Date:
26-Apr-2016
DOI:
10.3389/fmicb.2016.00571
Type:
Article
ISSN:
1664-302X
Sponsors:
This work was supported by a Global Research Partnership-Collaborative Fellows Award (GRP-CF-2011-13-P) from King Abdullah University of Science and Technology (KAUST), and by a Marie Curie Intra European Fellowship (SUREANMetOX-300078) within the 7th European Community Framework Programme. The assistance of Ludivine Thomas with the proteomic analysis at the Biosciences Core Laboratory at KAUST was highly appreciated. Special thanks are extended to the Advanced Nanofabrication Imaging and Characterization Core Laboratory team at KAUST: Rachid Sougrad for TEM 3-D reconstruction imaging and Ali Behzad for assistance with SEM-EDX analysis. Mohammed Alarawi (Biosciences Core Laboratory at KAUST) is thanked for generation of pyrosequencing reads. We also thank André A. M. Diederen from the Ballistics Laboratory at TNO Rijswijk in The Netherlands for fruitful discussions on impacting of Se0 spheres on bacterial cells.
Additional Links:
http://journal.frontiersin.org/Article/10.3389/fmicb.2016.00571/abstract
Appears in Collections:
Articles; Biological and Environmental Sciences and Engineering (BESE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorGonzalez-Gil, Gracielaen
dc.contributor.authorLens, Piet N. L.en
dc.contributor.authorSaikaly, Pascalen
dc.date.accessioned2016-05-23T13:05:38Z-
dc.date.available2016-05-23T13:05:38Z-
dc.date.issued2016-04-26-
dc.identifier.citationSelenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres 2016, 7 Frontiers in Microbiologyen
dc.identifier.issn1664-302X-
dc.identifier.doi10.3389/fmicb.2016.00571-
dc.identifier.urihttp://hdl.handle.net/10754/610579-
dc.description.abstractCertain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.en
dc.description.sponsorshipThis work was supported by a Global Research Partnership-Collaborative Fellows Award (GRP-CF-2011-13-P) from King Abdullah University of Science and Technology (KAUST), and by a Marie Curie Intra European Fellowship (SUREANMetOX-300078) within the 7th European Community Framework Programme. The assistance of Ludivine Thomas with the proteomic analysis at the Biosciences Core Laboratory at KAUST was highly appreciated. Special thanks are extended to the Advanced Nanofabrication Imaging and Characterization Core Laboratory team at KAUST: Rachid Sougrad for TEM 3-D reconstruction imaging and Ali Behzad for assistance with SEM-EDX analysis. Mohammed Alarawi (Biosciences Core Laboratory at KAUST) is thanked for generation of pyrosequencing reads. We also thank André A. M. Diederen from the Ballistics Laboratory at TNO Rijswijk in The Netherlands for fruitful discussions on impacting of Se0 spheres on bacterial cells.en
dc.language.isoenen
dc.publisherFrontiers Media SAen
dc.relation.urlhttp://journal.frontiersin.org/Article/10.3389/fmicb.2016.00571/abstracten
dc.rightsThis is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.http://creativecommons.org/licenses/by/4.0/en
dc.subjectseleniumen
dc.subjectanaerobic granulesen
dc.subjectmicrobial aggregatesen
dc.subjectgranular sludgeen
dc.subjectnanoparticlesen
dc.subjectnanospheresen
dc.subjectbiomineralizationen
dc.subjectbioreductionen
dc.titleSelenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheresen
dc.typeArticleen
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Divisionen
dc.contributor.departmentWater Desalination & Reuse Research Cntren
dc.identifier.journalFrontiers in Microbiologyen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Environmental Engineering and Water Technology, UNESCO-IHE Institute for Water Education, Delft, Netherlandsen
dc.contributor.affiliationKing Abdullah University of Science and Technology (KAUST)en
kaust.authorGonzalez-Gil, Gracielaen
kaust.authorSaikaly, Pascalen
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