Densifying lignocellulosic biomass with sulfuric acid provides a durable feedstock with high digestibility and high fermentability for cellulosic ethanol production

Agricultural residues (e.g. corn stover (CS)) representing a huge lignocellulosic biomass waste are regarded as a promising renewable resource that can be converted to fuels and chemicals via biochemical route. Nevertheless, the unfavorable properties, such as low bulk density, contamination by microorganisms, fluffy and thereby difficult to handle, cause huge problems for biomass logistics and biomass conversion. Furthermore, traditional biomass pretreatment methods often use severe conditions, consume much energy, difficult to scale up and generate a feedstock with many toxic degradation products that inhibit fermentation. In this study, we developed a novel, low-cost and easy-to-implement pretreatment method: Densifying Lignocellulosic biomass with acidic Chemicals (DLC) on CS. The DLCCS owning a uniform shape showed a bulk density 4 times higher compared to loose CS and was highly resistant to microbial contamination, which greatly facilitates biomass handling, transportation and storage. DLC-CS after regular steam autoclave treatment at 121 BC exhibited high enzymatic digestibility and much higher fermentability compared to traditional dilute acid pretreatment. An ethanol titer as high as 68.1 g/L was achieved without washing or detoxification of the pretreated biomass. The superior performances of DLC for biomass logistics and biomass conversion render it very promising for industrial use. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study developed a novel, low-cost pretreatment method to make lignocellulosic biomass easier to handle, transport, and store. This method can improve the enzymatic digestibility and fermentability of biomass, resulting in higher ethanol production compared to traditional methods.