Abstract
Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales. Though potentially competing for electrons with U(VI) reducers, homo-acetogens helped attain steady U(VI) reduction, while methanogenesis inhibited U(VI) reduction. U(VI) reduction was reinstated through suppression of methanogenesis by addition of bromoethanesulfonate or by competition from SRB when sulfate was re-introduced. Predictive metagenome analysis further points out community changes in response to alterations in the electron-acceptor loading: Sporulation and homo-acetogenesis were critical factors for strengthening stable microbial U(VI) reduction. This study documents that sporulation was important to long-term U(VI) reduction, whether or not microorganisms that carry out U(VI) reduction mediated by cytochrome c3, such as SRB and ferric-iron-reducers, were inhibited.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 341-349 |
| Number of pages | 9 |
| Journal | Water Research |
| Volume | 125 |
| DOIs | |
| State | Published - Nov 15 2017 |
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Keywords
- Acceptor loadings
- Homoacetogens
- Methanogens
- Spore-forming microorganisms
- Sulfate reducers
- Uranium reduction
ASJC Scopus subject areas
- Ecological Modeling
- Water Science and Technology
- Waste Management and Disposal
- Pollution
Cite this
Total electron acceptor loading and composition affect hexavalent uranium reduction and microbial community structure in a membrane biofilm reactor. / Ontiveros-Valencia, Aura; Zhou, Chen; Ilhan, Zehra Esra; de Saint Cyr, Louis Cornette; Krajmalnik-Brown, Rosa; Rittmann, Bruce.
In: Water Research, Vol. 125, 15.11.2017, p. 341-349.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Total electron acceptor loading and composition affect hexavalent uranium reduction and microbial community structure in a membrane biofilm reactor
AU - Ontiveros-Valencia, Aura
AU - Zhou, Chen
AU - Ilhan, Zehra Esra
AU - de Saint Cyr, Louis Cornette
AU - Krajmalnik-Brown, Rosa
AU - Rittmann, Bruce
PY - 2017/11/15
Y1 - 2017/11/15
N2 - Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales. Though potentially competing for electrons with U(VI) reducers, homo-acetogens helped attain steady U(VI) reduction, while methanogenesis inhibited U(VI) reduction. U(VI) reduction was reinstated through suppression of methanogenesis by addition of bromoethanesulfonate or by competition from SRB when sulfate was re-introduced. Predictive metagenome analysis further points out community changes in response to alterations in the electron-acceptor loading: Sporulation and homo-acetogenesis were critical factors for strengthening stable microbial U(VI) reduction. This study documents that sporulation was important to long-term U(VI) reduction, whether or not microorganisms that carry out U(VI) reduction mediated by cytochrome c3, such as SRB and ferric-iron-reducers, were inhibited.
AB - Molecular microbiology tools (i.e., 16S rDNA gene sequencing) were employed to elucidate changes in the microbial community structure according to the total electron acceptor loading (controlled by influent flow rate and/or medium composition) in a H2-based membrane biofilm reactor evaluated for removal of hexavalent uranium. Once nitrate, sulfate, and dissolved oxygen were replaced by U(VI) and bicarbonate and the total acceptor loading was lowered, slow-growing bacteria capable of reducing U(VI) to U(IV) dominated in the biofilm community: Replacing denitrifying bacteria Rhodocyclales and Burkholderiales were spore-producing Clostridiales and Natranaerobiales. Though potentially competing for electrons with U(VI) reducers, homo-acetogens helped attain steady U(VI) reduction, while methanogenesis inhibited U(VI) reduction. U(VI) reduction was reinstated through suppression of methanogenesis by addition of bromoethanesulfonate or by competition from SRB when sulfate was re-introduced. Predictive metagenome analysis further points out community changes in response to alterations in the electron-acceptor loading: Sporulation and homo-acetogenesis were critical factors for strengthening stable microbial U(VI) reduction. This study documents that sporulation was important to long-term U(VI) reduction, whether or not microorganisms that carry out U(VI) reduction mediated by cytochrome c3, such as SRB and ferric-iron-reducers, were inhibited.
KW - Acceptor loadings
KW - Homoacetogens
KW - Methanogens
KW - Spore-forming microorganisms
KW - Sulfate reducers
KW - Uranium reduction
UR - http://www.scopus.com/inward/record.url?scp=85028704381&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85028704381&partnerID=8YFLogxK
U2 - 10.1016/j.watres.2017.08.060
DO - 10.1016/j.watres.2017.08.060
M3 - Article
C2 - 28881210
AN - SCOPUS:85028704381
VL - 125
SP - 341
EP - 349
JO - Water Research
JF - Water Research
SN - 0043-1354
ER -