Amazonian arouma [Ischnosiphon arouma (Aubl.) Körn] as a novel source for cellulose-based bioplastics

The internal stem tissues of Ischnosiphon arouma (Aubl.) Körn, an Amazonian plant whose outer cortex is traditionally used in handicrafts, are typically discarded after processing. This study explores the potential of these inner, underutilized fractions as a viable source of high-quality cellulose. The extracted cellulose, obtained from all anatomical stem regions (cortex, conducting tissues, and pith), exhibited sufficient purity and structural homogeneity to enable its transformation into carboxymethyl cellulose (CMC), confirming its functional suitability. The resulting CMC was fully water-soluble and displayed favorable physicochemical properties for industrial use. Spectroscopic, thermal, and morphological analyses (ATR-FTIR, XRD, TGA, SEM-EDX) confirmed successful cellulose functionalization, with high crystallinity, good thermal stability, and a complete absence of silica in the final product, originally present in the raw cellulose, indicating effective purification. CMC-based bioplastic films were then formulated using glycerol or sorbitol as plasticizers and carnauba wax as an additive, yielding materials with promising barrier and UV-blocking properties suitable for food packaging. These findings highlight the valorization of residual biomass through a laboratory-scale process, facilitating the creation of functional, biodegradable materials. This approach fosters sustainable local value chains and supports circular bioeconomy strategies, particularly for niche and specialized products in tropical regions.