One-pot production of Carboxymethyl Holocelluloses from mango and pineapple wastes optimized via design of experiments

• APA treatment enhanced holocellulose extraction from mango and pineapple wastes; • One-pot carboxymethylation efficiently converted holocellulose into CMHC; • Optimized process achieved DS up to 1.63 and yields up to 249% (w/w); • ANOVA and RSM confirmed high process efficiency from 2:15h at milder conditions; • CMHCs show great potential for food, pharma, and oil drilling applications; The polysaccharide fraction of lignocellulosic biomass represents a promising resource for producing high value-added carbohydrate derivatives. This study aimed to develop a fast and sustainable one-pot process for synthesizing carboxymethyl holocellulose (CMHC) from pineapple crown (PACel) and mango seed tegument (MACel) abundant agro-food wastes, eliminating the need for polysaccharide separation. Holocellulose (cellulose and hemicellulose) was efficiently extracted using a mild acid/peroxide-alkali (APA) treatment, which preserved hemicellulose and generated highly reactive cellulose fractions detected by XRD. Carboxymethylation conditions were screened using a D-Optimal design of experiments, and the process was optimized via response surface methodology (RSM). Degree of substitution reached up to 1.63, with mass yields of up to 246.9% (w/w), surpassing literature values. Statistical models showed high accuracy (F > 36.36, p < 0.0001, R² > 0.9655). The proposed method offers higher reactivity, lower reagent consumption, and reduced processing time (2:15h), demonstrating the feasibility of converting agro-waste holocelluloses into high quality water-soluble CMHC products. This research contributes to the efficient valorization of underutilized bioresources in an innovative, rapid, scalable and more environmentally friendly biorefinery process, producing a viable alternative polymer to commercial CMC, with potential applications in the food, cosmetic, pharmaceutical, and oil drilling fluids industries.