Effect of protein during hydrothermal carbonization of brewer’s spent grain

• Published in: Bioresource technology 2019-12, Vol.293, p.122117, Article 122117
• Main Authors: Arauzo, P.J., Du, L., Olszewski, M.P., Meza Zavala, M.F., Alhnidi, M.J., Kruse, A.
• Format: Article
• Language: English
• Subjects: Amino acid profile; Brewer’s spent grain; Hydrothermal carbonization; Insoluble protein-rich fraction
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2019.122117

•After protein extraction: High C/N make hydrochars suitable for energy applications.•Thermal behavior of produced hydrochars is not affected by protein extraction process.•The essential amino acids were not influenced by extraction.•Proline is the main essential amino acid into protein extract. This study has two targets: Studying the extraction of the initial protein content from brewer’s spent grain and the impact of protein’s extraction on the chemical-physical properties of produced hydrochars. The protein was extracted from brewer’s spent grains using the pH-shifting method. The extracted protein was quantified and characterized by their amino acid profile. The hydrothermal treatment was applied at 190 °C and 220 °C for 0.5 h, 1 h, 2 h, and 4 h. The hydrochars and process water were collected and assayed. The hydrochar after protein extraction reveals the lowest yield to hydrochars (67.10–45.14%), higher C/N ratio (19.66–21.33) and lower ash content (1.52–1.72 wt%) compared to the hydrochar without extraction.