A sustainable approach for conversion of leather trimming wastes into non-edible gelatine and its physicochemical analysis, optimization, FTIR, XRD characterization, and statistical study

In recent decades, there has been a significant rise in the generation of solid waste from tanneries, primarily attributed to the accelerated pace of industrialization and the expanding economic activities. The conversion of biomass to energy with the production of gelatine from leather waste offers a promising approach to managing waste and utilizing resources sustainably. The leather industry byproducts, specifically raw leather trimmings waste, present an untapped resource for gelatine production. In this study, the optimal conditions for extracting gelatine from leather trimming waste were carried out. The ideal extraction conditions were found to be a temperature of around 80 °C for 4 h, using an acid concentration of 1.32%, yielding a maximum of 19.45%. Furthermore, for gelatine confirmation, qualitative analysis through biuret, ninhydrin, and hydroxyproline assays was carried out. The response surface methodology was applied to optimize extraction conditions, focusing on yield, moisture content, pH, and ash content. The gelatine showed comparable fat, protein content, and viscosity with respect to standard gelatine. The gelatine was additionally characterized by FTIR and XRD. FTIR analysis identified characteristic transmission bands at wavenumbers corresponding to amide I, II, and III, indicating the presence of organic and inorganic components. XRD analysis revealed both crystalline and amorphous phases in the gelatine. ANOVA confirmed the significant impact of extraction time, temperature, and acid concentration on the outcomes, validating the experimental design. This research emphasizes the significance of precise regulation of extraction parameters to maximize the production and quality of gelatine. It exemplifies an ecologically friendly method to valorize leather trimming waste.