Methane Production Using Brewery Spent Grain: Optimal Hydrothermolysis, Fermentation of Waste and Role of Microbial Populations

Author(s)

Gomes, Marina Mauro ^[1] ; Silva Rabelo, Camila Abreu B. ^[1] ; Sakamoto, Isabel Kimiko ^[1] ; Silva, Edson Luiz ^[2] ; Amancio Varesche, Maria Bernadete ^{[1, 3]}

Affiliation

^[1] Univ Sao Paulo, Sao Carlos Sch Engn, Dept Hydraul & Sanitat, Lab Biol Proc, Campus 2, BR-13563120 Sao Carlos, SP - Brazil

^[2] Univ Fed Sao Carlos, Ctr Exact Sci & Technol, Dept Chem Engn, BR-13565905 Sao Carlos, SP - Brazil

^[3] Univ Sao Carlos, Sch Engn Sao Carlos, Dept Hydraul & Sanitat, Lab Biol Proc, Av Jodo Dagnone 1100, BR-13563120 Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: WASTE AND BIOMASS VALORIZATION; v. 13, n. 2, SI SEP 2021.
• Web of Science Citations: 0

Abstract

The hydrothermolysis variables temperature (150-210 degrees C) and time (10-20 min) were assessed to improve hydrolysis efficiency of brewery spent grain (BSG) for renewable energy generation. The intensification of the pretreatment was expressed by the severity variation (2.8-4.5) and the process was optimized with methane production of 411.6 +/- 7.2 mL g(-1) TVS (severity 4.2). The fermentation-methanogenesis of BSG and hydrolysate resulting from BSG hydrothermolysis process under severity of 4.2 (210 degrees C for 10 min) was evaluated by central composite design with the variables operation temperature (30-60 degrees C), BSG concentration (7.3-20.7 g L-1) and hydrolysate (0-12.4 mL). The higher methane production observed was 305.8 mL g(-1) TVS, with 14 g L-1 of BSG, without hydrolysate at 45 degrees C. The main soluble metabolites were acetic acid (233.17 mg L-1) and butyric acid (156.0 mg L-1). On other hand, the lower methane production (108.5 +/- 2.0 mL g(-1) TVS) verified was 14 g L-1 of BSG, 6.5 mL of hydrolysate at 60 degrees C, which revealed that in this condition propionic acid (947.4 mg L-1) and acetic acid (599.2 mg L-1) were expressive. In the optimal fermentation-methanogenic condition of pretreated BSG, Macellibacteroides and Sphaerochaeta (15.9 and 14.7%, respectively) were identified, as well as archaea similar to Methanosaeta (80.4%), favoring the acetoclastic methanogenic pathway. {[}GRAPHICS] (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