TY - JOUR
T1 - Shifting the balance of fermentation products between hydrogen and volatile fatty acids
T2 - Microbial community structure and function
AU - Miceli, Joseph F.
AU - Torres, Cesar
AU - Krajmalnik-Brown, Rosa
N1 - Funding Information:
This work was supported by the National Institute of Health funded Arizona State University Institute for Maximizing Student Development [Grant Number R25GM099650], by the National Science Foundation CAREER Program [Grant Number 1053939], and by the United States Office of Naval Research [Grant Number N00014-10-M-0231].
Publisher Copyright:
© FEMS 2016.
PY - 2016
Y1 - 2016
N2 - Fermentation is a key process in many anaerobic environments. Varying the concentration of electron donor fed to a fermenting community is known to shift the distribution of products between hydrogen, fatty acids and alcohols. Work to date has focused mainly on the fermentation of glucose, and how the microbial community structure is affected has not been explored. We fed ethanol, lactate, glucose, sucrose or molasses at 100 me- eq. L-1, 200 me- eq. L-1 or 400 me- eq. L-1 to batch-fed cultures with fermenting, methanogenic communities. In communities fed high concentrations of electron donor, the fraction of electrons channeled to methane decreased, from 34% to 6%, while the fraction of electrons channeled to short chain fatty acids increased, from 52% to 82%, averaged across all electron donors. Ethanol-fed cultures did not produce propionate, but did show an increase in electrons directed to acetate as initial ethanol concentration increased. In glucose, sucrose, molasses and lactate-fed cultures, propionate accumulation co-occurred with known propionate producing organisms. Overall, microbial communities were determined by the substrate provided, rather than its initial concentration, indicating that a change in community function, rather than community structure, is responsible for shifts in the fermentation products produced.
AB - Fermentation is a key process in many anaerobic environments. Varying the concentration of electron donor fed to a fermenting community is known to shift the distribution of products between hydrogen, fatty acids and alcohols. Work to date has focused mainly on the fermentation of glucose, and how the microbial community structure is affected has not been explored. We fed ethanol, lactate, glucose, sucrose or molasses at 100 me- eq. L-1, 200 me- eq. L-1 or 400 me- eq. L-1 to batch-fed cultures with fermenting, methanogenic communities. In communities fed high concentrations of electron donor, the fraction of electrons channeled to methane decreased, from 34% to 6%, while the fraction of electrons channeled to short chain fatty acids increased, from 52% to 82%, averaged across all electron donors. Ethanol-fed cultures did not produce propionate, but did show an increase in electrons directed to acetate as initial ethanol concentration increased. In glucose, sucrose, molasses and lactate-fed cultures, propionate accumulation co-occurred with known propionate producing organisms. Overall, microbial communities were determined by the substrate provided, rather than its initial concentration, indicating that a change in community function, rather than community structure, is responsible for shifts in the fermentation products produced.
KW - Concentration
KW - Fermentation
KW - Methanogenesis
KW - Microbial community
KW - Propionate production
KW - Sugars
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U2 - 10.1093/femsec-fiw195
DO - 10.1093/femsec-fiw195
M3 - Article
C2 - 27633926
AN - SCOPUS:84995790813
SN - 0168-6496
VL - 92
JO - FEMS microbiology ecology
JF - FEMS microbiology ecology
IS - 12
M1 - fiw195
ER -