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Appl Microbiol Biotechnol. 2018 Sep;102(17):7643-7656. doi: 10.1007/s00253-018-9183-2. Epub 2018 Jun 29.

Physiology and methane productivity of Methanobacterium thermaggregans.

Author information

1
Archaea Physiology & Biotechnology Group, Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, Universität Wien, Althanstraße 14, 1090, Wien, Austria.
2
Krajete GmbH, Linz, Austria.
3
Department of Nanobiotechnology, University of Natural Resources and Life Sciences, Institute of Synthetic Bioarchitectures, Wien, Austria.
4
Johannes Kepler Universität Linz, Institute for Chemical Technology of Organic Materials, Linz, Austria.
5
Archaea Physiology & Biotechnology Group, Archaea Biology and Ecogenomics Division, Department of Ecogenomics and Systems Biology, Universität Wien, Althanstraße 14, 1090, Wien, Austria. simon.rittmann@univie.ac.at.

Abstract

Accumulation of carbon dioxide (CO2), associated with global temperature rise, and drastically decreasing fossil fuels necessitate the development of improved renewable and sustainable energy production processes. A possible route for CO2 recycling is to employ autotrophic and hydrogenotrophic methanogens for CO2-based biological methane (CH4) production (CO2-BMP). In this study, the physiology and productivity of Methanobacterium thermaggregans was investigated in fed-batch cultivation mode. It is shown that M. thermaggregans can be reproducibly adapted to high agitation speeds for an improved CH4 productivity. Moreover, inoculum size, sulfide feeding, pH, and temperature were optimized. Optimization of growth and CH4 productivity revealed that M. thermaggregans is a slightly alkaliphilic and thermophilic methanogen. Hitherto, it was only possible to grow seven autotrophic, hydrogenotrophic methanogenic strains in fed-batch cultivation mode. Here, we show that after a series of optimization and growth improvement attempts another methanogen, M. thermaggregas could be adapted to be grown in fed-batch cultivation mode to cell densities of up to 1.56 g L-1. Moreover, the CH4 evolution rate (MER) of M. thermaggregans was compared to Methanothermobacter marburgensis, the CO2-BMP model organism. Under optimized cultivation conditions, a maximum MER of 96.1 ± 10.9 mmol L-1 h-1 was obtained with M. thermaggregans-97% of the maximum MER that was obtained utilizing M. marburgensis in a reference experiment. Therefore, M. thermaggregans can be regarded as a CH4 cell factory highly suited to be applicable for CO2-BMP.

KEYWORDS:

Archaea; Biofuel; Bioprocess; Biorefinery; CH4; Fed-batch; Methanogen

PMID:
29959465
PMCID:
PMC6097776
DOI:
10.1007/s00253-018-9183-2
[Indexed for MEDLINE]
Free PMC Article

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