Communities stimulated with ethanol to perform direct interspecies electron transfer for syntrophic metabolism of propionate and butyrate

Addition of biochar and trace elements in the form of industrial FeCl3 to stabilize anaerobic digestion of food waste: dosage optimization and long‐term study

“…The concentrations of both HBu and valeric acid were much less significant than those of HAc and HPr. Interestingly and in accordance with the literature, HBu consumption was also favored by biochar addition . The average daily methane production was calculated by dividing the total volume of methane produced by the batch duration (i.e.…”

“…The kinetics of consumption of HAc and HBu were reported to be faster when adding biochar using glucose as substrate . Also the direct degradation of HPr and HBu has been improved by supplementing biochar and ethanol . Sunyoto et al .…”

“…The biochar was natural slow‐pyrolyzed wood charcoal, commonly found in the market for several applications. General characteristics reported for biochars with similar origins are: high carbon contents (78–84%), low sulfur proportions (0.1–0.5%), high pH of the water‐extractable fraction (8.6–9.6), Brunauer–Emmett–Teller surface areas of 130–210 m 2 g −1 and relatively high conductivities (4–5 µS cm −1 g −1 ) . Before utilization, the biochar was ground and sieved at 600 µm.…”

Enhancing anaerobic digestion of poultry blood using activated carbon

“…Direct interspecies electron transfer (DIET) is a syntrophic metabolism in which free electrons flow from one cell to another without being shuttled by reduced molecules such as molecular hydrogen or formate [42]. DIET has been suggested as the reason for obtaining better degradation rates of simple substrates and higher biogas yields in anaerobic systems when carbon-based conductive materials are added [43], as was demonstrated by Rotaru et al [44] and Zhao et al [45] when studying the use of activated carbon. In the present experiments, enhancement via DIET may be similarly relevant, as the improvement of digestion may not be completely explained by the adsorption phenomenon.…”

“…In a different study, Zhao et al [45] reported a change in microbial populations when evaluating anaerobic reactors for propionate/butyrate degradation with the aid of activated carbon. Methanosaeta and Methanosarcina species constituted a dominant part (81.49%) of the communities in their initial seed sludge, which significantly decreased when propionate and/or butyrate was used as the sole carbon source.…”