Microbial Succession during Thermophilic Digestion: The Potential of Methanosarcina sp

Paul Illmer,Andreas Otto Wagner,Philipp Lins,Christoph Reitschuler,Thomas Schwarzenauer,Melanie R Mormile

doi:10.1371/journal.pone.0086967

Paul Illmer, Andreas Otto Wagner + Show 4 more

Open Access

https://doi.org/10.1371/journal.pone.0086967

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Journal: PLoS ONE	Publication Date: Feb 19, 2014
Citations: 47	License type: CC BY 4.0

Affiliation: Universität Innsbruck

Abstract

A distinct succession from a hydrolytic to a hydrogeno- and acetotrophic community was well documented by DGGE (denaturing gradient gel electrophoresis) and dHPLC (denaturing high performance liquid chromatography), and confirmed by qPCR (quantitative PCR) measurements and DNA sequence analyses. We could prove that Methanosarcina thermophila has been the most important key player during the investigated anaerobic digestion process. This organism was able to terminate a stagnation phase, most probable caused by a decreased pH and accumulated acetic acid following an initial hydrolytic stage. The lack in Methanosarcina sp. could not be compensated by high numbers of Methanothermobacter sp. or Methanoculleus sp., which were predominant during the initial or during the stagnation phase of the fermentation, respectively.

Highlights

Irrespective of the disputed contribution of man to the global warming, the dramatic effects per se and the involvement of gases like CO2 and CH4 are unquestionable
The production of appreciable amounts of isobutyric acid and propionic acid took more time and concentrations reached approximately 1.5 mM and 3 mM at t = 1 and t = 4, respectively. At these levels the two acids remained remarkably constant till the second phase of high biogas production occurred
Results from phospholipid fatty acids (PLFA) analyses point to an increase of fatty acids typical for gram positive bacteria and confirm the absence of eukaryotic cells during the stagnation phase

Summary

Introduction

Irrespective of the disputed contribution of man to the global warming, the dramatic effects per se and the involvement of gases like CO2 and CH4 are unquestionable. Start up At the very beginning of the fermentation there was a distinct decrease in pH from about 7.5 to 6.6 connected with a sharp increase in the concentrations of H2 and CO2 in the headspace and the concentrations of acetic and butyric acid in the sludge.

Results

Conclusion