Green electrochemical approach for delignification of wheat straw in second-generation bioethanol production

Abstract

Ethanol is considered as one of the most promising next-generation automotive fuels, as it is carbon-neutral and can be produced from renewable resources, like lignocellulosic materials. However, owing to biomass characteristics, some technological barriers, such as delignification pretreatment, need to be addressed for an efficient conversion of wood to bioethanol. This paper describes a mild and harmless delignification of wheat straw, carried out at room temperature and requiring only 10 min, using an environmentally-friendly HOCl-containing electrochemically activated water solution, synthesized from diluted brines. Holocellulose (i.e. the sum of cellulose and hemicellulose) rich materials can be obtained with approximately 64% reduction of the initial lignin content. Both the absence of lignin degradation products, which could act as inhibitors during fermentation, and a promising, non-optimized ethanol yield (68% w/w on theoretical value) confirm the potential of this alternative approach towards resolving the challenges to develop a sustainable and low-cost process.