A comparative assessment of treatment methods to release ferulic and p-cumaric acids from Brewer’s Spent Grains

• Published in: Waste management (Elmsford) Vol. 188; pp. 39 - 47
• Main Authors: Bucci, P., Casas, A., Martins, P., Meyer, A., Cantero, D., Muñoz, R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 15.11.2024
• Subjects: Beer; Brewer’s spent grain; Carboxylic Ester Hydrolases - metabolism; Chemical treatment; Coumaric acid; Coumaric Acids; Edible Grain - chemistry; Endo-1,4-beta Xylanases - metabolism; Enzymatic treatment; Ferulic acid; Hydrolysis; Hydrothermal treatment; Industrial Waste - analysis; Propionates; Waste Management - methods; Coumaric acid; Enzymatic treatment; Hydrothermal treatment; Brewer’s spent grain; Chemical treatment; Ferulic acid
• ISSN: 0956-053X; 1879-2456; 1879-2456
• DOI: 10.1016/j.wasman.2024.07.025

•An effective recovery of antioxidants was obtained from breweŕs spent grain.•A comparison among chemical, enzymatic and hydrothermal hydrolysis was conducted.•The highest ferulic acid yield was 7.2 g FA/kg BSG for the hydrothermal treatment.•Alkaline hydrolysis showed the lowest operating costs: €34.5/kg FA at 100 kgBSG/m3. Brewers’ spent grain (BSG) is the main byproduct from the brewing industry, which accounts for 85 % of the total waste generated during beer production. This lignocellulosic material is traditionally used as livestock feed and sold at a low price. However, BSG can be used as a low-cost feedstock for the production of bioactive molecules and chemicals precursors, upgrading the value of this byproduct. In this context, BSG is a promising feedstock for the extraction of antioxidants like ferulic acid (FA) and p-coumaric acid (p-Cu). The effectiveness of three hydrolysis treatments were evaluated for the extraction of FA and p-Cu from BSG, namely enzymatic (based on the synergistic cooperation between a feruloyl esterase and an endo-1,4-β-xylanase), alkaline and hydrothermal. The hydrothermal treatment produced the highest extraction yields (7.2 g/kgBSG and 1.4 g/kgBSG for FA and p-Cu, respectively) in a short extraction time (an hour). On the other hand, enzymatic hydrolysis extracted 4.3 g/kgBSG for FA and negligible yields for p-Cu in 4 h of incubation at 25 °C. Yields of 5.5 g/kgBSG for FA and 0.6 g/kgBSG for p-Cu were obtained in more than 5 h of alkaline treatment at 120 °C. The mass and energy balances revealed the high dependence of the operating costs on the concentration of BSG used during the extraction process, with costs of 34.5 €, 6607 € and 205.5 € per kg of FA for the chemical, enzymatic and hydrothermal extraction methods at 100 kg BSG/m3.