Abstract
Large amounts of lignocellulosic-rich agricultural biomass waste are produced worldwide, making its proper management a key factor for a sustainable bioeconomy. Brazil is the fourth-largest banana producer in the world. After fruit harvesting, around four tons of wet biomass are generated for each ton of banana harvested. Converting these residues into value-added derivatives has attracted significant attention in recent years. In this context, this study proposes valorizing banana postharvest waste through cellulose extraction and purification, followed by the synthesis of Cellulose Acetate (CA) and Carboxymethylcellulose (CMC), highly versatile biomaterials that could potentially replace conventional polymers of industrial relevance. The efficiency of cellulose purification was evidenced by the low insoluble lignin (less than 2.18 %) and the high levels of a-cellulose (55.2 % to 79.5 %) in the bleached samples. The biopolymers synthesis was also confirmed by determining the degrees of substitution (DS) of CA (ranging from 2.87 to 2.89), and CMC (ranging from 0.77 to 0.85), as well as by identifying characteristic bands using Fourier Transform Infrared Spectroscopy (FT-IR), such as the peak at 1737 cm?¹ representing the stretching of the carbonyl ester of CA, and the peaks near 1587 cm?¹, confirming the elongation vibration of the carboxyl groups of CMC. These results demonstrate the viability of reusing lignocellulosic waste from banana postharvest processing to obtain high-value-added CA and CMC biopolymers, reinforcing their potential as a sustainable alternative in the valorization of agro-industrial waste.
