Potential of bioethanol production waste for methane recovery

Lignocellulosic biomass is emerging as an important feedstock for biofuel production. Bioethanol is one of the most common liquid biofuels in the transportation sector. However, its production process is still inefficient due to the large quantity of production waste that is left unused after the distillation process. In this paper, the biomethane potential of bioethanol production waste is analysed. The results are compared with the biomethane potential of samples from different stages of the bioethanol production process (pretreatment, hydrolysis and fermentation), and that of untreated biomass. In this study, barley straw is used as a biomass crop and N-2 explosive decompression (NED) is applied as a pretreatment method. The results show that bioethanol production waste has higher methane yields (1.17 mol CH4/100 g) than raw barley straw (1.04 mol CH4/100 g). Production waste also has a higher degradation rate (0.252) than untreated material (0.138), and achieves 95% of the maximum methane yield much faster (7.8 days) than untreated samples (22 days). This shows that production waste can be used for further anaerobic digestion (AD) to add value to the bioethanol production chain. NED pretreatment is an effective method of pretreatment. (C) 2019 Elsevier Ltd. All rights reserved.