Full details on continuous biohydrogen production from sugarcane molasses are unraveled: Performance optimization, self-regulation, metabolic correlations and quanti-qualitative biomass characterization

Author(s)

Fuess, Lucas Tadeu ^{[1, 2]} ; Fuentes, Laura ^[3] ; Bovio-Winkler, Patricia ^[3] ; Eng, Felipe ^[2] ; Etchebehere, Claudia ^[3] ; Zaiat, Marcelo ^[2] ; Oller do Nascimento, Claudio Augusto ^[1]

Affiliation

^[1] Univ Sao Paulo, Polytech Sch, Chem Engn Dept, Av Prof Lineu Prestes 580, Bloco 18, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo EESC USP, Sao Carlos Sch Engn, Biol Proc Lab, Av Joao Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

^[3] Biol Res Inst Clemente Estable, Dept Biochem & Microbial Genom, Microbial Ecol Lab, 3318 Italia Ave, Montevideo - Uruguay

• Document type: Journal article
• Source: CHEMICAL ENGINEERING JOURNAL; v. 414, JUN 15 2021.
• Web of Science Citations: 4

Abstract

Using pure sugars for fermentative biohydrogen (bioH2) production is known as an economically impeditive approach due to the high costs of raw materials, which leads to the frequent exploitation of residual streams. However, the potentials of using biodigestion as a core processing step in sugarcane biorefineries opens up a wide range of biotechnological possibilities, in which sugar-rich materials may be fermented without adding acquisition costs. This study aimed to finalize the full optimization of the continuous longterm (630 d) thermophilic (55 ?C) bioH2 production from molasses, defining adequate hydraulic retention time (HRT) levels. Details of temporal and spatial metabolite distribution profiles coupled to the characterization of microbial communities provided the most complete picture of molasses acidogenesis to date. BioH2 evolution (8.5 NL-H2 L-1 d-1) in full optimized conditions, i.e., HRT ?10.0 h, organic loading rate (OLR) ?86.0 kg-CODt m- 3 d-1 and pH ?5.38, exceeded the individual application of optimal OLR (4.5 NLH2 L-1 d-1) and pH (2.4 NL-H2 L-1 d-1) by almost 200% and 350%, respectively. Biomass washout naturally controlled substrate availability (6.21 ? 2.1 g-COD g- 1VSS d-1 for over 300 d), preventing performance losses in the long-term. BioH2 derived from acetic- and butyric-type fermentations was observed in the basal portion of the reactor, whilst butyrate and bioH2 from reverse ?-oxidation using lactate prevailed in the bed region. The Thermoanaerobacterium genus was the main group involved in such pathways, and the contribution of the Caproiciproducens genus in caproate production was also revealed.\& nbsp;These findings provide consistent directions to scale-up acidogenic systems towards an effective exploitation of full-scale bioH2 production. (AU)

• 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
• 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: 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: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Grantee: Julio Romano Meneghini
• Support Opportunities: Research Grants - Research Centers in Engineering Program