Document Detail


Inhibition of biohydrogen production by undissociated acetic and butyric acids.
MedLine Citation:
PMID:  16382963     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Glucose fermentation to hydrogen results in the production of acetic and butyric acids. The inhibitory effect of these acids on hydrogen yield was examined by either adding these acids into the feed of continuous flow reactors (external acids), or by increasing glucose concentrations to increase the concentrations of acids produced by the bacteria (self-produced). Acids added to the feed at a concentration of 25 mM decreased H2 yields by 13% (acetic) and 22% (butyric), and 60 mM (pH 5.0) of either acid decreased H2 production by >93% (undissociated acid concentrations). H2 yields were constant at 2.0 +/- 0.2 mol H2/mol glucose for an influent glucose concentration of 10-30 g/L. At 40 g glucose/L, H2 yields decreased to 1.6 +/- 0.1 mol H2/mol glucose, and a switch to solventogenesis occurred. A total undissociated acid concentration of 19 mM (self-produced acids) was found to be a threshold concentration for significantly decreasing H2 yields and initiating solventogenesis. Hydrogen yields were inhibited more by self-produced acids (produced at high glucose feed concentrations) than by similar concentrations of externally added acids (lower glucose feed concentrations). These results show the reason hydrogen yields can be maximized by using lower glucose feed concentrations is that the concentrations of self-produced volatile acids (particularly butyric acid) are minimized.
Authors:
Steven Van Ginkel; Bruce E Logan
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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.    
Journal Detail:
Title:  Environmental science & technology     Volume:  39     ISSN:  0013-936X     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2005 Dec 
Date Detail:
Created Date:  2005-12-30     Completed Date:  2006-04-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  9351-6     Citation Subset:  IM    
Affiliation:
Department of Civil and Environmental Engineering, Penn State University, University Park, PA 16802, USA.
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MeSH Terms
Descriptor/Qualifier:
Acetic Acids / chemistry*
Butyric Acids / chemistry*
Hydrogen / chemistry*
Hydrogen-Ion Concentration
Chemical
Reg. No./Substance:
0/Acetic Acids; 0/Butyric Acids; 1333-74-0/Hydrogen

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


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