The beamhouse plays a pivotal role in leather manufacturing. However, the conventional lime-sulfide system (LSS) used in the beamhouse causes significant environmental pollution due to the extensive use of chemical agents. In recent years, most research has focused on biological treatments, with enzymes emerging as a promising environmentally friendly alternative. In this study, we employed the salt-enzyme system (SES) to utilize MgCl₂-assisted neutral protease to streamline processes and reduce pollution in the beamhouse. Additionally, response surface methodology (RSM) was utilized to optimize the experimental conditions for enhancing unhairing, fiber opening, and bating efficiency. In terms of environmental benefits, compared to LSS, SES exhibits a significant decrease in COD, NH₃-N, and TS by 9.59%, 26.27%, and 76.94%, respectively, highlighting its efficacy as an environmentally sustainable alternative. The environmental impacts of the beamhouse stage (LCA) approach by comparing two scenarios. The results showed that all the environmental significantly lower than those linked to LSS. The utilization of MgCl₂-assisted neutral protease in a one-step beamhouse aligns with the trend of environmentally friendly and green production for the leather industry.

Leather manufacturing is increasingly prioritizing environmentally friendly processes, emphasizing clean production to reduce environmental impacts. The present work explored the application of an α-amylase/neutral protease system (ANS) in a simplified, one-step process for unhairing, fiber opening, and bating as a viable alternative to the traditional, chemically intensive lime-sulfide system (LSS). Utilizing response surface methodology (RSM), we developed a mathematical model to optimize operational conditions, resulting in an effective concentration of 0.3 wt.% α-amylase and 0.5 wt.% neutral protease at 28.4℃ over 16.6 hours. The effectiveness of the process on unhairing and fiber opening was assessed through scanning electron microscopy (SEM), and the impact on bating was evaluated by the removal rates of carbohydrate and proteoglycan. The leather produced using the optimized ANS  exhibited physical properties comparable to those processed traditionally, with the higher hydrothermal shrinkage temperature and increased softness. Environmentally, the optimized ANS process achieved significant reductions in pollutants, cutting over 90% of chemical oxygen demand (COD), NH₃-N, and Cl^-, and reducing total solids (TS) by 73.91%. A cost analysis further revealed a direct cost savings of 30.98% when using the ANS compared to the LSS, alongside indirect savings from enhanced production efficiency and simplified wastewater treatment. Notably, the one-step enzymatic beamhouse approach substantially lowers electricity and water usage, potentially reducing greenhouse gas emissions by 44.6%. This investigation underscores the potential of ANS as a sustainable, cost-effective approach for leather manufacturing that supports environmentally friendly practices.