Dynamics of sulfate reduction in the thermophilic dark fermentation of sugarcane vinasse: A biohydrogen-independent approach targeting enhanced bioenergy production

Author(s)

Piffer, Michael Antonio ^[1] ; Zaiat, Marcelo ^[1] ; do Nascimento, Claudio Augusto Oller ^[2] ; Fuess, Lucas Tadeu ^{[2, 1]}

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Biol Proc Lab, EESC, USP, Av Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

^[2] Univ Sao Paulo, Polytech Sch, Chem Engn Dept, Av Prof Lineu Prestes 580, Bloco 18, BR-05508000 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: JOURNAL OF ENVIRONMENTAL CHEMICAL ENGINEERING; v. 9, n. 5 OCT 2021.
• Web of Science Citations: 0

Abstract

Dark fermentation (DF) systems usually exploit bioH(2) production aiming to improve the energetic potential (EP) of anaerobic digestion (AD) schemes. In the case of sulfate-rich substrates, the versatility of fermentative consortia may favor the establishment of sulfidogenic conditions, minimizing/eliminating the competition between sulfate-reducing bacteria (SRB) and methanogens in the sequential stage and providing sulfide-free biogas. This study details the establishment of sulfidogenesis on the thermophilic DF of sugarcane vinasse in a continuous polyurethane-filled fixed-film reactor, also estimating the EP for vinasses according to different AD-related approaches. High sodium levels naturally stimulated SRB by maintaining high pH values (> 6.0), whilst NaHCO3 dosing was required when natural buffering conditions were not maintained. High acetate (similar to 3 g-COD L-1) and COD/sulfate ratio (> 25.0) levels indicated a high-quality substrate for further methanogenesis. High butyrate concentrations (similar to 11 g-COD L-1) coupled to caproate detection indicated the occurrence of chain elongation processes, leading to low bioH(2) production levels (<400 NmL-H(2)L(-1)d(-1)). However, estimates indicated 12.2%-and 51.7%-increases in the methane-based EP (MJ m(-3)) of sulfate-free fermented vinasse (216.72) relative to sulfate-rich fermented (193.10) and fresh (142.88) vinasses. Hence, the ultimate approach for maximizing bioenergy production from sugarcane vinasse is detailed in this study. (AU)

• FAPESP's process: 15/50684-9 - Sustainable gas pathways for Brazil: from microcosm to macrocosm
• Grantee: Reinaldo Giudici
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program
• FAPESP's process: 17/00080-5 - Enhancement of energy production from sugarcane in first generation biorefineries: biodigestion as the core conversion step
• Grantee: Lucas Tadeu Fuess
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 15/06246-7 - Biorefinery concept applied to biological wastewater treatment plants: environmental pollution control coupled with material and energy recovery
• Grantee: Marcelo Zaiat
• Support Opportunities: Research Projects - Thematic Grants