Desconstrução da biomassa lignocelulósica com solvente eutético profundo seguido de hidrólise com extrato enzimático de Aspergillus niger 11T53A14

Abstract

The main stages of bioethanol production from lignocellulosic biomass are pre-treatment, enzymatic hydrolysis, and fermentation. The technical-economic feasibility of producing this biofuel depends on the development of an efficient, economic, and ecological pre-treatment. In this scenario, deep eutectic solvents (DES) have shown promise, because in addition to being less harmful to the environment and relatively economical, these solvents have shown efficiency in the deconstruction of lignocellulose. Among DES, the one formed by choline chloride (ChCl) and lactic acid has been highlighted in the literature. In this context, the objective of this work was to evaluate the efficiency of the pretreatment with DES formed by ChCl and lactic acid in the deconstruction of the lignocellulosic structure of sugarcane bagasse and in the increase of the yield of sugars after enzymatic hydrolysis. For this, the pre-treatment was carried out at 80 ºC, with 0.05 g/mL of biomass for different treatment times with and without subsequent washing of the biomass with 60% (v/v) ethanol. Chemical and structural analyzes such as FTIR, TGA, SEM and DRX were performed, as well as enzymatic hydrolysis of fresh and pre-treated biomass. The total cellulase activity produced by Aspergillus niger 11T53A14 by solid state fermentation was 0.37 (±0.025) IU/g. Enzymes produced by A. niger 11T53A14 maintained their activities at low concentrations of DES. Lignin removal with 12 h pretreatment at 80°C and ethanol washing was estimated at 63.6% and cellulose recovery at 77.4%. Structural analyzes corroborated the composition results, indicating a promotion of deconstruction of lignocellulosic biomass by the studied DES.