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Methanogenic consortia from thermophilic molasses-fed structured-bed reactors: microbial characterization and responses to varying food-to-microorganism ratios

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Autor(es):
Fuess, Lucas Tadeu ; Eng, Felipe ; Bovio-Winkler, Patricia ; Etchebehere, Claudia ; Zaiat, Marcelo ; Nascimento, Claudio Augusto Oller do
Número total de Autores: 6
Tipo de documento: Artigo Científico
Fonte: Brazilian Journal of Chemical Engineering; v. N/A, p. 21-pg., 2022-12-15.
Resumo

The heterogeneous character of fixed-film reactors may create highly specialized zones with a stratified distribution of microbial groups and varying capabilities to withstand high organic loads in anaerobic digestion (AD) systems. The microbial distribution and methane-producing potential of biomass from different regions (feeding zone and structured bed) of two second-stage thermophilic (55 oC) fixed-film reactors were assessed. Three levels of food-to-microorganism (F/M) ratio (0.4, 1.0 and 3.0 g-COD g(-1)VS) using fermented (two-stage AD) and fresh (single-stage AD) sugarcane molasses were tested in batch reactors, simulating low to high organic loads. Specific methane production rates increased as the F/M increased when using fermented molasses, maintaining efficient methanogenesis at substrate availability levels threefold higher than single-stage schemes (3.0 vs. 1.0 g-COD g(-1)VS). Success in methane production derived from the homogenous establishment (similar in both feeding zone and bed) of syntrophic associations between acetogens (Pelotomaculum, Syntrophothermus, Syntrophomonas and Thermodesulfovibrio), acetate oxidizers (Thermoacetogenium, Mesotoga and Pseudothermotoga) and hydrogenotrophic methogens (Methanothermobacter and Methanoculleus) replacing acetoclastic methanogens (Methanosaeta). Phase separation under thermophilic conditions was demonstrated to boost methane production from sugar-rich substrates, because the process depends on microbial groups (hydrogenotrophs) that grow faster and are less susceptible to low pH values compared to acetotrophs. (AU)

Processo FAPESP: 17/00080-5 - Potencialização da produção de energia a partir da cana-de-açúcar em biorrefinarias de primeira geração: biodigestão como etapa central de conversão
Beneficiário:Lucas Tadeu Fuess
Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
Processo FAPESP: 15/06246-7 - Aplicação do conceito de biorrefinaria a estações de tratamento biológico de águas residuárias: o controle da poluição ambiental aliado à recuperação de matéria e energia
Beneficiário:Marcelo Zaiat
Modalidade de apoio: Auxílio à Pesquisa - Temático
Processo FAPESP: 14/50279-4 - Brasil Research Centre for Gas Innovation
Beneficiário:Julio Romano Meneghini
Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
Processo FAPESP: 15/50684-9 - Sustainable gas pathways for Brazil: from microcosm to macrocosm
Beneficiário:Reinaldo Giudici
Modalidade de apoio: Auxílio à Pesquisa - Temático