Hydrogen and organic acid production from dark fermentation of sugarcane vinasse without buffers in mesophilic and thermophilic conditions

Author(s)

Ribeiro, Jaqueline Cardoso ^[1] ; Mota, Vera Taina ^[2] ; de Oliveira, Valeria Maia ^[2] ; Dacanal, Gustavo Cesar ^[3] ; Zaiat, Marcelo ^[1]

Affiliation

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

^[2] Univ Estadual Campinas CPQBA Unicamp, Div Recursos Microbianos, Ctr Pluridisciplinar Pesquisas Quim Biol & Agr, Paulinia - Brazil

^[3] Univ Sao Paulo FZEA USP, Fac Zootecnia & Engn Alimentos, Pirassununga - Brazil

• Document type: Journal article
• Source: JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY; DEC 2021.
• Web of Science Citations: 0

Abstract

BACKGROUND Sugarcane vinasse has a low pH and several studies report that alkalinity supplementation is essential to the stability of its dark fermentation (DF). In the context of biorefineries, the reduction, or even elimination, of alkalinizing agents could be extremely environmentally and economically advantageous. The main objective of this study was to evaluate the valorisation of vinasse DF through bioH(2) and value-added metabolite production without buffers in two similar Upflow Anaerobic Sludge Blanket (UASB) under mesophilic (U30) and thermophilic (U55) conditions. RESULTS Average organic acid yields of 376 +/- 52 and 248 +/- 122 mg-CODOA.g(-1)CODt(in), and productivities of 17 396 +/- 5220 and 14 024 +/- 1642 mg-CODOA.L-1 day(-1) were obtained for U30 and U55 reactors, respectively, with only vinasse as substrate (CODOA stands for organic acids chemical oxygen demand (COD) and CODin influent COD). BioH(2) production was feasible with sucrose as substrate and pH below 3.0, but it ceased with substrate replacement by vinasse along with a natural pH increase. A change in microbial community was also observed: Ethanoligenens, Clostridium sensu stricto 12, and Liquorilactobacillus (using sucrose and with a pH <3.0) were replaced by Prevotella, Megasphaera, Pectinatus, Clostridium sensu stricto 11, and Lactobacillus using vinasse (with a pH > 4.0). CONCLUSION Results showed that DF of sugarcane vinasse without any buffering addition might be a promising approach for the valorization of real wastewater through the production of organic acids. Nevertheless, bioH(2) production was not favored and further strategies would be needed to maintain hydrogen-producing bacteria when sucrose is replaced by real effluent with a natural pH increase. (c) 2021 Society of Chemical Industry (SCI). (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: 18/25645-8 - Omics approaches in acidogenic reactors without alkalization for organic acid and hydrogen production
• Grantee: Vera Tainá Franco Vidal Mota
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 17/06940-6 - Evaluation of acidogenic and methanogenic anaerobic reactors in the treatment of vinasse and whey without alkalination
• Grantee: Jaqueline Cardoso Ribeiro
• Support Opportunities: Scholarships in Brazil - Doctorate