Physical Pretreatments Applied to Lignocellulose Biomass: A Review

This article provides an overview of the physical pretreatments that can be applied to lignocellulosic biomass and their different benefits. It focuses on and compiles information on the main physical pretreatments applied to lignocellulose biomass, including the concept, advantages, disadvantages, and parameters of the pretreatments (milling, ultrasound, and microwave). A review of research carried out on different types of biomasses and what was obtained from them is also provided. Milling provides an essential mechanical change to optimize the surface, while microwave and ultrasonic methods provide sophisticated techniques that greatly increase the efficiency of transforming biomass through selective structural modification. The physical pretreatment goal is to improve the efficiency of conversion processes and increase the economic viability of using biomass as a renewable and sustainable source of energy and chemical products. The use of the energy of lignocellulosic biomass requires the proper implementation of pretreatments that facilitate the obtaining of biofuels and high-value biochemical products such as hemicellulose, lignin, and glucose derivatives, for example, ethanol, xylitol, butanol, and acetoacetic acid.