PH and organic carbon dose rates control microbially driven bioremediation efficacy in alkaline bauxite residue

Santini, Talitha C., Malcolm, Laura I., Tyson, Gene W. and Warren, Lesley A. (2016) PH and organic carbon dose rates control microbially driven bioremediation efficacy in alkaline bauxite residue. Environmental Science and Technology, 50 20: 11164-11173. doi:10.1021/acs.est.6b01973


Author Santini, Talitha C.
Malcolm, Laura I.
Tyson, Gene W.
Warren, Lesley A.
Title PH and organic carbon dose rates control microbially driven bioremediation efficacy in alkaline bauxite residue
Journal name Environmental Science and Technology   Check publisher's open access policy
ISSN 1520-5851
0013-936X
Publication date 2016-10-18
Year available 2016
Sub-type Article (original research)
DOI 10.1021/acs.est.6b01973
Open Access Status Not yet assessed
Volume 50
Issue 20
Start page 11164
End page 11173
Total pages 10
Place of publication Washington, DC, United States
Publisher American Chemical Society
Language eng
Abstract Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling, the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H+ produced per day with pH decreasing from 9.5 to <= 6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.
Formatted abstract
Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H+ produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.
Keyword Uranium-Mine Tailings
Escherichia-Coli
Copy Number
Community
Fermentation
Bioaugmentation
Environments
Bacteria
Failure
Culture
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

 
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