Document Detail

Stability in a denitrifying fluidized bed reactor.
MedLine Citation:
PMID:  16874554     Owner:  NLM     Status:  MEDLINE    
This study evaluates changes in the microbial community structure and function of a pilot-scale denitrifying fluidized bed reactor during periods of constant operating conditions and periods of perturbation. The perturbations consisted of a shutdown period without feed, two disturbances in which biofilms were mechanically sheared from carrier particles, and a twofold step increase in feed nitrate concentration. In the absence of perturbations, nitrate removal was stable and consistently greater than 99%. The structure and dynamics of the microbial community were studied using cloning and sequencing techniques and terminal restriction fragment length polymorphism (T-RFLP) of the SSU rRNA gene. Under unperturbed operating conditions, stable function was accompanied by high constancy and low variability of community structure with the majority of terminal restriction fragments (T-RFs) appearing throughout operation at consistent relative abundances. Several of the consistently present T-RFs correlated with clone sequences closely related to Acidovorax (98% similarity), Dechloromonas (99% similarity), and Zoogloea (98% similarity), genera recently identified by molecular analyses of similar systems. Significant changes in community structure and function were not observed after the shutdown period. In contrast, following the increase in loading rate and the mechanical disturbances, new T-RFs appeared. After both mechanical disturbances, function and community structure recovered. However, function was much more resilient than community structure. The similarity of response to the mechanical disturbances despite differences in community structure and operating conditions suggests that flexible community structure and potentially the activity of minor members under nonperturbation conditions promotes system recovery.
M Gentile; T Yan; S M Tiquia; M W Fields; J Nyman; J Zhou; C S Criddle
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2006-07-28
Journal Detail:
Title:  Microbial ecology     Volume:  52     ISSN:  0095-3628     ISO Abbreviation:  Microb. Ecol.     Publication Date:  2006 Aug 
Date Detail:
Created Date:  2006-09-12     Completed Date:  2006-11-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7500663     Medline TA:  Microb Ecol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  311-21     Citation Subset:  IM    
Department of Civil and Environmental Engineering, Stanford University, Stanford, CA, USA.
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MeSH Terms
Biodegradation, Environmental
Cloning, Molecular
Gene Library
Gram-Positive Bacteria / classification,  genetics,  physiology*
Nitrates / metabolism*
Nitrogen / metabolism
Pilot Projects
Polymorphism, Restriction Fragment Length
Proteobacteria / classification,  genetics,  physiology*
Water Purification*
Reg. No./Substance:
0/Nitrates; 7727-37-9/Nitrogen

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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