@misc{OttoWitkabelBarthetal., author = {Otto, Pascal and Witkabel, Philipp and Barth, Maximilian and Ammar, Aziz Ben and Rocktaeschel, Benjamin and Torrent, Daniel and Latorre-Per{\´e}z, Adriel and Krause, Maximilian and Abendroth, Christian}, title = {Adaptation of the anaerobic microbiome for in-situ power-to-CH4 processes through fuzzy logic control of H2 input}, series = {Bioresource technology reports}, volume = {31}, journal = {Bioresource technology reports}, publisher = {Elsevier BV}, address = {Amsterdam}, issn = {2589-014X}, doi = {10.1016/j.biteb.2025.102194}, pages = {1 -- 11}, abstract = {This study presents the first application of fuzzy logic control (FLC) for regulating in-situ biological methanation via H2 injection in a fixed-bed reactor. Given the role of CH4 as a storable and infrastructure-compatible energy carrier, the aim was to improve CH4 production by dynamically adapting the H2 supply to the metabolic capacity of the microbiome. This will pave the way for the biological utilisation and storage of renewable H2. Over a 226- day operational period, H2 input was gradually increased based on real-time headspace gas measurements. Coupling the gradual increase in H2 supply with real-time gas composition data allowed the microbiome to adapt dynamically to changing process conditions. This approach led to a 49 \% increase in CH4 concentration, from 58.4 \% to 87.0 \%, and improved H2 conversion rates from 98.2 \% to 99.0 \%. Chemical analyses of COD, organic acids and nitrogen were performed, as well as taxonomic analyses using 16S rRNA sequencing, and multivariate methods were applied to confirm the adaptation of the microbiome to the FLC H2 injection. The adopted microbial community was dominated by strictly hydrogenotrophic methanogens, Methanoculleus and Methanobacterium, while increased abundances of Petrimonas, Rectinema, Syntrophomonas, and Geobacter indicate interspecies H2 transfer and syntrophic cooperation enhancing methanogenesis. These findings demonstrate that FLC-based H2 control enables dynamic adjustment of in-situ methanation, optimising the interaction between hydrogenogenic, fermentative, syntrophic acetate-oxidising, and hydrogenotrophic microorganisms. This work introduces an adaptive control strategy that supports stable and efficient bio-CH4 production and represents a significant advance in the field of power-to-gas technologies.}, language = {en} } @misc{HozadAbendroth, author = {Hozad, Ahmad Shabir and Abendroth, Christian}, title = {Electro-composting : an emerging technology}, series = {Fermentation}, volume = {11}, journal = {Fermentation}, number = {7}, publisher = {MDPI AG}, address = {Basel}, issn = {2311-5637}, doi = {10.3390/fermentation11070401}, pages = {1 -- 23}, abstract = {This study focuses on electrical stimulation for composting. Using the PSALSAR method, a comprehensive systematic review analysis identified 22 relevant articles. The examined studies fall into four main systems: electric field-assisted aerobic composting (EAAC), electrolytic oxygen aerobic composting (EOAC), microbial fuel cells (MFCs), and thermoelectric generators (TEGs). Apart from the main systems highlighted above, bioelectrochemically assisted anaerobic composting (AnCBE, III) is discussed as an underexplored system with the potential to improve the efficiency of anaerobic degradation. Each system is described in terms of key materials, composter design, operating conditions, temperature evolution, compost maturity, microbial community, and environmental outcomes. EAAC and EOAC systems accelerate organic matter decomposition by improving oxygen distribution and microbial activity, whereas MFC and TEG systems have dual functioning due to the energy generated alongside waste degradation. These innovative systems not only significantly improve composting efficiency by speeding up organic matter breakdown and increasing oxygen supply but also support sustainable waste management by reducing greenhouse gas emissions and generating bioelectricity or heat. Together, these systems overcome the drawbacks of conventional composting systems and promote future environmental sustainability solutions.}, language = {en} } @misc{Puchol‐RoyoPascualOrtega‐Legarretaetal., author = {Puchol-Royo, Roser and Pascual, Javier and Ortega-Legarreta, Asier and Otto, Pascal and Tideman, Jeroen and de Vries, Sjoerd-Jan and Abendroth, Christian and Tanner, Kristie and Porcar, Manuel and Latorre-Perez, Adriel}, title = {Metagenomic insights into the ecology, taxonomy and metabolic capabilities of 'Candidatus Darwinibacteriales' Ord. Nov. (formerly MBA03), a potential key player in anaerobic digestionstion}, series = {Microbial biotechnology}, volume = {18}, journal = {Microbial biotechnology}, number = {12}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {1751-7915}, doi = {10.1111/1751-7915.70258}, pages = {1 -- 16}, abstract = {Biogas, a mix of CO2, CH4 and small proportions of other gases, is a biofuel obtained by anaerobic digestion (AD). Biogas production is often considered a black box process, as the role and dynamics of some of the microorganisms involved remain undisclosed. Previous metataxonomic studies in the frame of the MICRO4BIOGAS project (www. micro 4biog as. eu) revealed that MBA03, an uncharacterised and uncultured bacterial taxon belonging to phylum Bacillota, was very prevalent and abundant in industrial full-scale AD plants. Despite the efforts, this taxon has not yet been cultivated, which makes the analysis of its taxonomy, ecology and metabolism even more challenging. In the present work, 30 samples derived from anaerobic digesters were sequenced, allowing the reconstruction of 108 metagenome-assembled genomes (MAGs) potentially belonging to MBA03. According to phylogenetic analyses and genomic similarity indices, MBA03 was classified as a new bacterial order, proposed as 'Candidatus Darwinibacteriales' ord. nov., which includes 'Candidatus Darwinibacter acetoxidans' gen. nov., sp. nov. of 'Candidatus Darwinibacteriaceae' fam. nov., along with 'Candidatus Wallacebacter cryptica' gen. nov., sp. nov. of the 'Candidatus Wallacebacteriaceae' fam. nov. Ecotaxonomic studies determined that AD processes are the main ecological niche of 'Candidatus Darwinibacteriales'. Moreover, metabolic predictions identified Darwinibacteraceae members as putative syntrophic acetate-oxidising bacteria (SAOB), as they encode for the reversed Wood-Ljungdahl (W-L) pathway coupled to the glycine cleavage system. This suggests that Darwinibacteraceae members could work in collaboration with hydrogenotrophic methanogenic archaea to produce methane in industrial biogas plants. Overall, our findings present 'Candidatus Darwinibacteriales' as a potential key player in anaerobic digestion and pave the way towards the complete characterisation of this newly described bacterial taxon, which has not yet been cultured.}, language = {en} }