Effect of different pretreatments of Passiflora edulis peel biomass on the conversion process into bioproducts for biorefineries

Abstract

The industrial processing of passion fruit (Passiflora edulis f. flavicarpa) generates large amounts of lignocellulosic residues that are of great economic, scientific, and technological interest. This study investigated different pretreatments – aqueous, acidic and basic – aided by ultrasound. It also verified their influence on the chemical and physical aspects of passion fruit peel and on the yield of carbohydrates, 5-hydroxymethylfurfural (HMF) and furfural (FF). The pretreatments followed a complete factorial experimental design to obtain the optimal conditions varying in concentration (2.5 % and 5 % HCl; 4 % and 8 % NaOH) and time (0.5 and 1 h) for carbohydrate yield and increased accessibility to cellulose and hemicellulose. These results were analyzed by HPLC, FT-IR and X-ray diffraction analysis. Optimized conditions for the pretreatment were 2.5 % HCl, 4 % NaOH and aqueous with a sonication time of 1 h. The pretreatments tested increased the efficiency of the hydrolysis. The highest yields of glucose (5.05 g/L), HMF (0.09 g/L), and FF (0.99 g/L) were recorded from the hydrolysis pretreated with HCl 2.5 % at 1 h. This study demonstrated the potential of using passion fruit peel in biorefinery processes, adding value to waste and promoting sustainability.