Methane Production Using Brewery Spent Grain: Optimal Hydrothermolysis, Fermentation Of Waste And Role Of Microbial Populations

Abstract

The hydrothermolysis variables temperature (150 - 210 °C) and time (10 - 20 minutes) 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 STV (severity 4.2). The fermentation-methanogenesis of BSG and hydrolysate resulting from BSG hydrothermolysis process under severity of 4.2 (210 o C for 10 min.) was evaluated by central composite design (CCD) with the variables operation temperature (30 - 60 °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 STV, with 14 g.L -1 of BSG, without hydrolysate at 45 °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 STV) verified was 14 g.L -1 of BSG, 6.5 mL of hydrolysate at 60 °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.

Focos de calor e desempenho de índices de perigo de incêndios no período de 2017 a 2021 em Jataí – Goiás

“…Entretanto, o Cerrado interage de forma diferente com o fogo, podendo ser considerado um fator natural e de evolução desse bioma, contribuindo para a manutenção da estrutura, da biodiversidade e o funcionamento dos ecossistemas (Durigan e Ratter 2015;Schmidt et al 2016). Independentemente disso, a ignição dos incêndios florestais no Brasil está ligada à ação humana, tanto de forma intencional como por negligência, e sua propagação ocorre a partir da interação entre fatores topográficos, climáticos e vegetacionais (Gomes et al 2020;Patriota et al 2017).…”