Publications by authors named "P Tsapekos"

It is known that the presence of sulfate decreases the methane yield in the anaerobic digestion systems. Sulfate-reducing bacteria can convert sulfate to hydrogen sulfide competing with methanogens for substrates such as H and acetate. The present work aims to elucidate the microbial interactions in biogas production and assess the effectiveness of electron-conductive materials in restoring methane production after exposure to high sulfate concentrations.

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To substitute petroleum-based materials with bio-based alternatives, microbial fermentation combined with inexpensive biomass is suggested. In this study Saccharina latissima hydrolysate, candy-factory waste, and digestate from full-scale biogas plant were explored as substrates for lactic acid production. The lactic acid bacteria Enterococcus faecium, Lactobacillus plantarum, and Pediococcus pentosaceus were tested as starter cultures.

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Article Synopsis
  • The study evaluated three different inhibitors on microorganisms from Archaea and Bacteria to see their impact on CO biomethanation during biogas upgrading.
  • Both ETH2120 and CO promoted methane production when added, while BES did not, indicating that archaea in the mix were inactive without the first two.
  • Although acetate was produced in all conditions, higher levels of CO reduced acetate output while boosting methane production, suggesting intricate interactions within the complex microbial community.
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Seaweed biomass has been proposed as a promising alternative carbon source for fermentation processes using microbial factories. However, the high salinity content of seaweed biomass is a limiting factor in large scale fermentation processes. To address this shortcoming, three bacterial species (Pediococcus pentosaceus, Lactobacillus plantarum, and Enterococcus faecium) were isolated from seaweed biomass and evolved to increasing concentrations of NaCl.

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Research within biological methanation has been a great development using biotrickling filters (BTF), as a power-to-x solution, but research within up scaling is missing. This study investigates the commercial potential of biomethanation in BTF by operating two 1 m reactors which was implemented into a full-scale biogas plant. Several areas were investigated, such as enrichment and start-up, long-term steady state operation, serial operation, and intermittent feed.

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