Diversity of fiber-adherent bacteria on three potential bioenergy feedstocks during digestion in the cow rumen

Yannarell, A. C., Hess, M., Hugenholtz, P. and Mackie, R. I. (2009). Diversity of fiber-adherent bacteria on three potential bioenergy feedstocks during digestion in the cow rumen. In: Conference on Gastrointestinal Function, Chicago, USA, (585-585). 20–22 April 2009. doi:10.1007/s00248-009-9496-x

Author Yannarell, A. C.
Hess, M.
Hugenholtz, P.
Mackie, R. I.
Title of paper Diversity of fiber-adherent bacteria on three potential bioenergy feedstocks during digestion in the cow rumen
Conference name Conference on Gastrointestinal Function
Conference location Chicago, USA
Conference dates 20–22 April 2009
Journal name Microbial Ecology   Check publisher's open access policy
Place of Publication New York, NY United States
Publisher Springer
Publication Year 2009
Sub-type Published abstract
DOI 10.1007/s00248-009-9496-x
ISSN 0095-3628
Volume 57
Issue 3
Start page 585
End page 585
Total pages 1
Language eng
Formatted Abstract/Summary
The large-scale use of grains for bioenergy (ethanol) production is undesirable because it detracts from human and animal food supplies. Efficient fermentation of plant cell walls will facilitate the shift to “second generation,” cellulose-based bioenergy feedstocks, such as perennial grasses. Rumen microorganisms, which constitute a highly efficient system for cellulose fermentation, may point the way to economically feasible bioethanol production. The goal of this work is to characterize the diversity of fiberadherent rumen bacteria on three potential bioenergy feedstocks: corn stover, switchgrass (Panicum virgatum), and Miscanthus X giganteus. These feedstocks were incubated in live cows for 72 h, followed by DNA extraction (fibrous material and rumen fluid) and microbial community characterization by bacterial ARISA (automated ribosomal intergenic spacer analysis) and T-RFLP (terminal restriction fragment length polymorphism). In addition, subsamples of switchgrass were removed periodically over the course of a 72-h live incubation to investigate bacterial colonization dynamics. Fiber-adherent microbial biomass (indicated by total extractable DNA) increased rapidly over the first hour of incubation, and then slowly doubled over the course of the following 71 h. Final microbial biomass varied between  the feedstocks and between cows. The richness of bacterial phylotypes, assessed with ARISA, also varied by feedstock and cow, but the fiber-adherent communities were consistently more diverse than that of rumen fluid. The colonization of switch grass fibers occurred in several stages. Fiber associated bacteria increased from an initial 9 phylotypes to over 150 phylotypes after 2 h, but then richness and evenness dropped dramatically, fluctuating between 30 and 90 phylotypes for the duration. Both T-RFLP and ARISA indicated that fiber-associated communities were distinct from those of rumen fluid. Within each cow, different feedstocks accumulated different communities, but these differences tended to be smaller than  differences observed between cows. Thus, the colonization of plant fibers in the rumen is a dynamic process, and the composition of the fiber-associated microbiota depends both on the feedstock and on factors specific to each individual cow rumen.
Keyword Fermentation
Bioenergy feedstock
Q-Index Code EX
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Conference Paper
Collection: School of Chemistry and Molecular Biosciences
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