Unlocking the potential of ionic liquid assisted fractionation of grapevine shoots for efficient fermentable sugar production and lignin recovery

Abstract

The global transition from a fossil-based to a sustainable bio-based economy highlights the need for renewable resources to obtain bioenergy and bioproducts. Vine shoots (VS), an abundant non-edible biomass from vine pruning, have significant potential for biorefinery processes. This research investigates the use of ionic liquids (ILs) like 1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]), 1-butyl-3-methylimidazolium hydrogen sulphate ([BMIM][HSO4]) and 1-ethyl-3-methylimidazolium ethyl sulphate ([EMIM][ESO4]) to pretreat VS, enhancing enzymatic digestibility and lignin recovery. ILs can effectively fractionate lignocellulosic biomass. Experimental conditions, including temperature, water addition to ILs and washing agents significantly influence the process. High cellulose (86.0 %) and xylan (95.7 %) conversion rates were achieved using [EMIM][Ac]: H2O, and delignification up to 42.5 % using [BMIM][HSO4]: H2O. The study also examines process intensification, with favorable results at up to 20 % biomass loading. The recyclability of ILs suggests a sustainable circular process, though efficiency decreases need to be addressed. Recycled ILs can depolymerize lignin into valuable phenolic compounds, adding further value. Overall, IL-assisted fractionation presents a green and efficient method for processing VS biomass, essential for sustainable biorefinery integration and commercial use. This research lays the groundwork for future studies on ILs in VS biomass pretreatment, emphasizing the need for careful IL selection and process conditions.