Densifying lignocellulosic biomass with sodium hydroxide provides stable quality feedstock for ethanol production without high temperature and high pressure processes.

Pretreatment is a key step in the formation of biofuels and has pervasive impacts on other major operation steps in the overall biorefinery. Nevertheless, low bulk density, microbial contamination, inefficient processing and high-temperature or high-pressure operations during pretreatment cause huge problems for biomass logistics and biomass conversion. In this work, we developed a novel, efficient and easy-to-operate pretreatment technology: Densifying lignocellulosic biomass with sodium hydroxide (DLC(sh)) for corn stover (CS). A systematic investigation into the effects of DLC(sh) pretreatment on the biomass logistics, enzymatic hydrolysis, and microbial fermentation performance of lignocellulosic feedstocks will enable a comprehensive evaluation of DLC(sh) pretreatment technology's viability in commercial application. DLC(sh) pretreatment owning high bulk density and uniform shape, greatly facilitates feedstock handling, transportation and storage. The DLC(sh) pretreatment densified CS with low energy consumption, which avoided the use of high-temperature or high-pressure equipment and scaled up for pretreated biomass. DLC(sh)-CS showed highly enzymatic digestibility (glucan and xylan conversion>90 %) and highly fermentability (0.219 g ethanol/g dry corn stover) without detoxification of the pretreated biomass. Hence, these results demonstrated that DLC(sh) pretreatment has great commercial potential to convert corn stover to ethanol.