Production and Application of Lignin-Based Chemicals and Materials in the Cellulosic Ethanol Production: An Overview on Lignin Closed-Loop Biorefinery Approaches

Lignocellulosic biomass is the most abundant biological resource on the planet and has been extensively researched to produce cellulosic ethanol. However, there is a consensus that the presence of lignin hinders the biomass conversion. Lignin is often considered a villain in cellulosic ethanol production studies due to its adverse effects on cellulases and yeasts. Despite this, recent studies indicate that lignins can be transformed into useful inputs to produce cellulosic ethanol. These approaches aim to establish closed-loop biorefineries to improve economic metrics and reduce the environmental impact due to the substitution of products based on fossil sources. The present review addresses the successful cases in transforming lignin into chemicals and materials to increase cellulosic ethanol titers. A contextualization was first carried out, considering aspects of biomass characteristics and lignin valorization. The impact of lignin-based chemicals and materials in the pretreatment, detoxification, and enzymatic hydrolysis steps was discussed in detail. Economic aspects and future perspectives were also included in this review. These reports open a new point of view on lignin valorization and its integration with the cellulosic ethanol production chain. [GRAPHICS] .

Automated summary

Lignocellulosic biomass is a rich resource on Earth, but lignin is often seen as a hindrance to biomass conversion. Recent studies show that lignin can be transformed into useful products for cellulosic ethanol production. These approaches aim to establish closed-loop biorefineries for better economic performance and reduced environmental impact.