Sulfate- and pH-driven metabolic flexibility in sugarcane vinasse dark fermentation stimulates biohydrogen evolution, sulfidogenesis or homoacetogenesis

Autor(es)

Piffer, Michael Antonio ; Oliveira, Cristiane Arruda ; Bovio-Winkler, Patricia ; Eng, Felipe ; Etchebehere, Claudia ; Zaiat, Marcelo ; do Nascimento, Claudio Augusto Oller ; Fuess, Lucas Tadeu

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; v. 47, n. 73, p. 21-pg., 2022-08-26.

Resumo

Dark fermentation of sugarcane vinasse can be used as a "cleaning" step to remove sulfate prior to methanogenesis because sulfidogenic conditions can be successfully established in parallel with biohydrogen production. Using a 2(2) central composite rotational design (CCRD) and response surface methodology (RSM), this study assessed the impacts of bicarbonate and sulfate availability on the establishment of sulfidogenesis in the thermophilic (55 degrees C) fermentation of vinasse in batch reactors, equally assessing the impacts on biohydrogen evolution. CCRD-RSM results indicated the favoring of biohydrogen production at the lowest sulfate and bicarbonate concentrations, whilst the opposite was observed for sulfidogenesis. Glycerol, lactate, and hydrogen were the preferential electron donors utilized by sulfate-reducing bacteria (SRB), whilst ethanol was markedly consumed only at high sulfate concentrations. SRB were inhibited by sodium when dosing excess NaHCO3 and Na2SO4. Complementary tests revealed maximum biohydrogen production (2.40 mmol) out of the CCRD, at pH exceeding 7.5 with no interference of sulfidogenesis. Non-efficient biohydrogen production was observed at low pH (<5.0; similar to 1.90 mmol) because the uptake of lactate was inhibited. Meanwhile, homoacetogenesis was established under intermediate pH range (5.5-6.5), as revealed by the accumulation of acetate (up to 2.5 g L-1). 16S rRNA gene amplicon sequencing further revealed the genera Thermoanaer- obacterium/Pseudoclostridium, Desulfotomaculum/Desulfohalotomaculum and Sporomusaceae/Moorella as the main biohydrogen-producing, sulfate-removing and biohydrogen-consuming (homoacetogens) microbial groups, respectively. Hence, using a single inoculum source, vinasse may provide a butyrate-rich (along with biohydrogen-rich biogas) or a sulfate-free and acetate-rich fermented effluent, depending mainly on proper pH control. (C) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. (AU)

• 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: 15/06246-7 - 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: 20/03429-1 - Investigação dos impactos da redução de sulfato na atividade hidrogenogênica durante a fermentação termofílica da vinhaça de cana-de-açúcar
• Beneficiário: Michael Antonio Piffer
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 15/50684-9 - Sustainable gas pathways for Brazil: from microcosm to macrocosm
• Beneficiário: Reinaldo Giudici
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• 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