Goat Skin (Capra aegagruss Erxleben, 1777): a Promising and Sustainable Source of Collagen

The aim of the study was to extract and characterize collagen from solid untanned skin waste from the processing of leather in a Capra aegagrus tannery. Using pepsin (SPC), 37 g of collagen were obtained from 100 g of dry weight skin. Characterization took place using SDS-PAGE, FTIR and UV absorption techniques, identifying it as type I collagen. The ultraviolet (UV) absorption spectrum showed a peak at 238 nm. In the thermogram, the maximum transition temperature was 56º C. Using the electrophoresis technique, it was observed that SPC consists of band patterns formed by a γ chain, a β chain and two distinct α chains (α1 and α2). In the FTIR analysis, the collagen showed the absorption peaks for the amides, showing that the SPC extraction process maintained the integrity of the molecule. To observe the effect of NaCl concentration on the solubility of SPC, the collagen showed high solubility, up to a concentration of 2% NaCl. The solubility peak was observed at pH 4.0, with a sharp drop until pH 7.0, reaching its minimum point at pH 10. Scanning microscopy showed some irregular surfaces, cavities and fibrous structures, which may favor the application of collagen as a biomaterial. The zeta potential found the isoelectric point of collagen at pH = 6.61. These results indicate that the collagen obtained has a high level of structural integrity and can be applied as an alternative source, as well as adding value to a waste product that is often discarded in the environment.