Document Detail


Shaping reactor microbiomes to produce the fuel precursor n-butyrate from pretreated cellulosic hydrolysates.
MedLine Citation:
PMID:  22894772     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
To maximize the production of carboxylic acids with open cultures of microbial consortia (reactor microbiomes), we performed experiments to understand which factors affect the community dynamics and performance parameters. We operated six thermophilic (55°C) bioreactors to test how the factors: i. biomass pretreatment; ii. bioreactor operating conditions; and iii. bioreactor history (after perturbations during the operating period) affected total fermentation product and n-butyrate performance parameters with corn fiber as the cellulosic biomass waste. We observed a maximum total fermentation product yield of 39%, a n-butyrate yield of 23% (both on a COD basis), a maximum total fermentation production rate of 0.74 g COD l-1 d-1 and n-butyrate production rate of 0.47 g COD l-1 d-1 in bioreactors that were fed with dilute-acid pretreated corn fiber at a pH of 5.5. Pyrosequencing of 16S rRNA genes with constrained ordination and other statistical methods showed that changes in operating conditions to dilute toxic carboxylic acid products, which lead to these maximum performance parameters, also altered the composition of the microbiome, and that the microbiome, in turn, affected the performance. Operating conditions are an important factor (tool for operators) to shape reactor microbiomes, but other factors, such as substrate composition after biomass pretreatment and bioreactor history are also important. Further optimization of operating conditions must relieve the toxicity of carboxylic acids at acidic bioreactor pH levels even more, and this can, for example, be accomplished by extracting the product from the bioreactor solutions.
Authors:
Matthew T Agler; Jeffrey J Werner; Loren B Iten; Arjan Dekker; Michael A Cotta; Bruce Dien; Largus T Angenent
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-8-15
Journal Detail:
Title:  Environmental science & technology     Volume:  -     ISSN:  1520-5851     ISO Abbreviation:  Environ. Sci. Technol.     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-8-16     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0213155     Medline TA:  Environ Sci Technol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
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