Advanced Bioethanol Production: From Novel Raw Materials to Integrated Biorefineries

TLDR

Advanced bioethanol production uses nonfood crops or residual biomass and offers higher sustainability and lower greenhouse gas emissions than traditional processes. This review surveys recent advances in advanced bioethanol, covering novel biomass sources, innovative pretreatment methods, enzyme and microbial developments, and biorefinery strategies aimed at cost‑competitiveness and full biomass utilization. The authors highlight integrated lignocellulosic biorefineries employing bioextrusion, ionic‑liquid pretreatments, and novel enzymes or microbial strains to simultaneously produce bioethanol and high‑value co‑products.

Abstract

The production of so-called advanced bioethanol offers several advantages compared to traditional bioethanol production processes in terms of sustainability criteria. This includes, for instance, the use of nonfood crops or residual biomass as raw material and a higher potential for reducing greenhouse gas emissions. The present review focuses on the recent progress related to the production of advanced bioethanol, (i) highlighting current results from using novel biomass sources such as the organic fraction of municipal solid waste and certain industrial residues (e.g., residues from the paper, food, and beverage industries); (ii) describing new developments in pretreatment technologies for the fractionation and conversion of lignocellulosic biomass, such as the bioextrusion process or the use of novel ionic liquids; (iii) listing the use of new enzyme catalysts and microbial strains during saccharification and fermentation processes. Furthermore, the most promising biorefinery approaches that will contribute to the cost-competitiveness of advanced bioethanol production processes are also discussed, focusing on innovative technologies and applications that can contribute to achieve a more sustainable and effective utilization of all biomass fractions. Special attention is given to integrated strategies such as lignocellulose-based biorefineries for the simultaneous production of bioethanol and other high added value bioproducts.