| Title | Enhancing methane production from food waste fermentate using biochar: the added value of electrochemical testing in pre-selecting the most effective type of biochar |
| Abstract | BACKGROUND:
Recent studies have suggested that addition of electrically conductive biochar particles is an effective strategy to improve the methanogenic conversion of waste organic substrates, by promoting syntrophic associations between acetogenic and methanogenic organisms based on interspecies electron transfer processes. However, the underlying fundamentals of the process are still largely speculative and, therefore, a priori identification, screening, and even design of suitable biochar materials for a given biotechnological process are not yet possible.
RESULTS:
Here, three charcoal-like products (i.e., biochars) obtained from the pyrolysis of different lignocellulosic materials, (i.e., wheat bran pellets, coppiced woodlands, and orchard pruning) were tested for their capacity to enhance methane production from a food waste fermentate. In all biochar-supplemented (25 g/L) batch experiments, the complete methanogenic conversion of fermentate volatile fatty acids proceeded at a rate that was up to 5 times higher than that observed in the unamended (or sand-supplemented) controls. Fluorescent in situ hybridization analysis coupled with confocal laser scanning microscopy revealed an intimate association between archaea and bacteria around the biochar particles and provided a clear indication that biochar also shaped the composition of the microbial consortium. Based on the application of a suite of physico-chemical and electrochemical characterization techniques, we demonstrated that the positive effect of biochar is directly related to the electron-donating capacity (EDC) of the material, but is independent of its bulk electrical conductivity and specific surface area. The latter properties were all previously hypothesized to play a major role in the biochar-mediated interspecies electron transfer process in methanogenic consortia.
CONCLUSIONS:
Collectively, these results of this study suggest that for biochar addition in anaerobic digester operation, the screening and identification of the most suitable biochar material should be based on EDC determination, via simple electrochemical tests. |
| Source | Biotechnology for biofuels 10 (303), pp. Article number 303 |
| Keywords | Anaerobic digestionBiocharDirect interspecies electron transfer (DIET)Electron-donating capacity (EDC)Food wasteMethane |
| Journal | Biotechnology for biofuels |
| Editor | BioMed Central, [London], Regno Unito |
| Year | 2017 |
| Type | Articolo in rivista |
| DOI | 10.1186/s13068-017-0994-7 |
| Authors | Viggi C. C., Simonetti S., Palma E., Pagliaccia P., Braguglia C., Fazi S., Baronti S., Navarra M. A., Pettiti I., Koch C., Harnisch F., Aulenta F. |
| Text | 381831 2017 10.1186/s13068 017 0994 7 ISI Web of Science WOS 000417959400003 Scopus 2 s2.0 85041210672 Anaerobic digestion Biochar Direct interspecies electron transfer DIET Electron donating capacity EDC Food waste Methane Enhancing methane production from food waste fermentate using biochar the added value of electrochemical testing in pre selecting the most effective type of biochar Viggi C. C., Simonetti S., Palma E., Pagliaccia P., Braguglia C., Fazi S., Baronti S., Navarra M. A., Pettiti I., Koch C., Harnisch F., Aulenta F. Water Research Institute IRSA , National Research Council CNR , via Salaria km 29,300, Monterotondo, 00015, Italy; Institute of Biometeorology IBIMET , National Research Council CNR , via G. Caproni 8, Florence, 50145, Italy; Department of Chemistry, Sapienza University of Rome, Piazzale Aldo Moro 5, Rome, 000185, Italy; Department of Environmental Microbiology, Helmholtz Centre for Environmental Research GmbH UFZ, Permoserstr. 15, Leipzig, 04318, Germany. BACKGROUND Recent studies have suggested that addition of electrically conductive biochar particles is an effective strategy to improve the methanogenic conversion of waste organic substrates, by promoting syntrophic associations between acetogenic and methanogenic organisms based on interspecies electron transfer processes. However, the underlying fundamentals of the process are still largely speculative and, therefore, a priori identification, screening, and even design of suitable biochar materials for a given biotechnological process are not yet possible. RESULTS Here, three charcoal like products i.e., biochars obtained from the pyrolysis of different lignocellulosic materials, i.e., wheat bran pellets, coppiced woodlands, and orchard pruning were tested for their capacity to enhance methane production from a food waste fermentate. In all biochar supplemented 25 g/L batch experiments, the complete methanogenic conversion of fermentate volatile fatty acids proceeded at a rate that was up to 5 times higher than that observed in the unamended or sand supplemented controls. Fluorescent in situ hybridization analysis coupled with confocal laser scanning microscopy revealed an intimate association between archaea and bacteria around the biochar particles and provided a clear indication that biochar also shaped the composition of the microbial consortium. Based on the application of a suite of physico chemical and electrochemical characterization techniques, we demonstrated that the positive effect of biochar is directly related to the electron donating capacity EDC of the material, but is independent of its bulk electrical conductivity and specific surface area. The latter properties were all previously hypothesized to play a major role in the biochar mediated interspecies electron transfer process in methanogenic consortia. CONCLUSIONS Collectively, these results of this study suggest that for biochar addition in anaerobic digester operation, the screening and identification of the most suitable biochar material should be based on EDC determination, via simple electrochemical tests. 10 Published version https //biotechnologyforbiofuels.biomedcentral.com/articles/10.1186/s13068 017 0994 7 Enhancing methane production from food waste fermentate using biochar... versione pubblicata s13068 017 0994 7.pdf Articolo in rivista BioMed Central 1754 6834 Biotechnology for biofuels Biotechnology for biofuels Biotechnol. biofuels Biotechnology for biofuels PAGLIACCIA PAMELA PALMA ENZA stefano.fazi FAZI STEFANO camillamaria.braguglia BRAGUGLIA CAMILLA MARIA federico.aulenta AULENTA FEDERICO carolina.cruzviggi CRUZ VIGGI CAROLINA silvia.baronti BARONTI SILVIA |
