Aqueous ethanol organosolv process for the valorization of Brewer's spent grain (BSG)

Brewers spent grain (BSG), the main solid byproduct of brewing, is annually generated by ca 37 million tons worldwide, which due to limited application, mostly ends up in landfills. This study aims to separate BSG's fractions (lignin, cellulose, and hemicellulose) by ethanol organosolv pretreatment. Lignin-rich fractions were recovered using a two-step separation technique. The effects of temperature, retention time, and ethanol concentration on the quantity and quality of fractions were studied. The temperature considerably impacted the quality and quantity of obtained fractions, while other parameter effects greatly depended on the temperature. Substantial hemicellulose removal (90 %) along with lignin removal (56 %) and recovery (57 %) were obtained at 180 degrees C. The highest lignin purity (95 %) was obtained at the pretreatment conditions of 180 degrees C, 120 min, and 50 % ethanol concentration. This work provides an alternative mute for BSG utilization, mitigating its environmental impact while enhancing the economy of a brewery.

Automated summary

This study aimed to separate the fractions of Brewers spent grain (BSG) by ethanol organosolv pretreatment. The effects of temperature, retention time, and ethanol concentration on the quantity and quality of fractions were studied. Significant hemicellulose removal and lignin recovery were achieved at 180 degrees C.