Optimization of Papain Enzyme Activity Using a Response Surface Methodology Approach

Enzyme-based leather dehairing has become widely recognized as a more environmentally friendly alternative to conventional chemical processes. In recent decades, the demand for plant-based enzymes has grown, leading to the need to improve catalytic efficiency and meet industrial requirements through advanced extraction and isolation techniques. Therefore, the objective of this study was to extract plant papain enzyme from <i>Carica papaya</i> and evaluate their potential as a dehairing agent in the leather industry. The experimental study was conducted in a laboratory setting from July to August 2023. <i>Carica papaya</i> samples were collected from various locations in Arba Minch town. Papain enzyme was extracted from <i>Carica papaya</i> by grinding it in a blender with extraction media such as distilled water and 50 mM phosphate buffers. The optimization of proteolytic activity was performed using the response surface method and Box-Behnken Design (BBD), considering parameters like pH, temperature, and reaction time. The optimized conditions for temperature, pH, and reaction time were found to be 55°C, 7.5, and 38.5 minutes, respectively, resulting in an optimum protease activity of 32 U/ml. The crude protease enzyme derived from papaya was successfully used to dehair goat hides at 25°C for 16 hours without the addition of Na<sup>2</sup>S. Microscopic analysis revealed hides that were free of epidermis and hair, with clean pores and no significant damage to the grain surface. In conclusion, the papain enzyme derived from <i>Carica papaya</i> can be a valuable tool for implementing cleaner technologies in tanneries, particularly for lime and sulphide-free dehairing processes.