Greener and cleaner: The industrial potential of cold-active and Alkaliphilic proteases

Abstract

The global imperative for sustainable development is driving a paradigm shift across industries, prioritizing eco-friendly processes that minimize energy consumption and chemical pollution. In this transition towards "green chemistry," enzymes have emerged as nature's premier catalysts, offering high specificity and efficiency under mild conditions. Among these, proteases sourced from extremophilic microorganisms—specifically cold-active proteases from psychrophiles and alkaliphilic proteases from alkaliphiles—stand out for their remarkable potential. This review provides a comprehensive analysis of the industrial significance of these two classes of extremozymes. We delve into their microbial sources, the unique molecular adaptations that enable their function in extreme cold and high pH, and the "activity-flexibility-stability" trade-off that governs their performance. A substantial body of evidence is synthesized to highlight their transformative applications in major industrial sectors, including the detergent industry, where they enable energy-saving cold-water washing and stain removal in alkaline formulations; the leather industry, where they offer a clean alternative to toxic dehairing chemicals; and the food and pharmaceutical industries. We critically examine the role of modern protein engineering techniques, such as directed evolution and rational design, in tailoring these enzymes for enhanced stability and catalytic efficiency. Furthermore, the review addresses the current limitations, including enzyme stability and production costs, and outlines future directions, focusing on metagenomic discovery, AI-driven enzyme design, and advanced immobilization technologies. Cold-active and alkaliphilic proteases represent key enabling technologies for a cleaner, more sustainable industrial future.