Hot Water Pretreatment

Hot water pretreatment (HWP) is a green and mild method for biorefinery. The characteristic of HWP is that it takes place at a certain temperature (100–250 °C) and pressure without any chemicals or organic solvents involved. This chapter reviews the literature advances on HWP of three representative biomasses with diverse biochemical components, including carbohydrate-rich lignocellulosic biomass, protein-rich algae, and complex sludge. Specifically, how HWP influences subsequent anaerobic digestion (AD) is discussed in detail. This includes enhancing hydrolysis and liquefaction of biomass, increasing the anaerobic biodegradability, and possible inhibitor release and control. The important parameters impacting HWP were introduced including temperature, retention time, pressure, and pretreatment severity. The perspective and challenges are finally summarized. This review provides a recent summary and insight for the studies on HWP and its influence on AD.