Simultaneous production of dry solid biomass and liquid extract from Sorghum bicolor using liquefied ammonia

Abstract

Energy-consuming processes should be avoided while separating biomass components. This study investigated the dewatering and extraction of components from Sorghum bicolor silage using liquefied NH3 (NH3(l)). Using a plug-flow-type reactor, NH3(l) was passed through the specimen at 20 °C and 0.85 MPa. When the NH3/wet sample weight was 4.7, a 31.0 wt% dry ammonia-treated sample (AT) was obtained as an extract, achieving a 96.5 wt% dewatering ratio. Glucose, xylose, and an acid-insoluble fraction were retained in the AT, whereas lactic and acetic acids were separated as an extract. Crystalline cellulose was transformed, and the increase in glucose and xylose yields from the enzymatic hydrolysis of the AT was similar levels to those from sulfuric acid hydrolysis. Therefore, NH3(l) treatment can dewater S. bicolor silage without severe pretreatment. In addition, it can be used in biofuel and chemical production using enzymatically degradable ATs from which organic acids are separated as extracts.