Editorial: Mining, Designing, Mechanisms and Applications of Extremophilic Enzymes

Abstract

Enzymes play very important roles in industrial and environmental biotechnology. Their value has increased in recent decades mainly in food and detergent industries and is still growing, particularly in bioremediation (white biotechnology), and in medical, pulp/paper, textile, energy, and biosensor applications (Fernández-Lucas et al., 2017). Recent assessments have evaluated the global enzyme market at more than $7,000 million, and the business is estimated to rapidly exceed $10,000 million (Fernández-Lucas et al., 2017; Pasqualetti et al., 2019). Enzyme technologies provide economically viable and eco-friendly alternatives. The number of commercial enzymes continues to increase as we exploit, by traditional or molecular screening/selection methods, the astonishing microbial diversity to obtain new bio-catalysts and expand their range of application (Petruccioli et al., 1993; Xiao et al., 2015; Sysoev et al., 2021). Most extremophilic enzymes (extremozymes) come from microorganisms. Extremozymes remain active and stable in extreme conditions, such as high pH values, high salinity and hydrostatic pressure, and temperature extremes. They often have unique properties empowering them to satisfy the needs of many harsh industrial processes. From a commercial viewpoint, enzymes with high activity and adaptation to diverse extreme conditions show growing demand, since current applications of many existing enzymes are still constrained by activity, stability, and/or economic issues. One solution to this problem is searching for new enzymes from natural sources that show high activity/stability, uncommon specificity, and poly-extremophilic features (thermo/psychrophilic, acid/alkalophilic, and halophilic properties). However, not all extremozymes are isolated from extreme environments. Another winning strategy, which is expected to improve enzyme properties for biotechnological application, is protein engineering (Xiao et al., 2015; Liu et al., 2019). The objective of this Research Topic was to inspect new details in this growing research field, and to obtain a deeper understanding of the area, allowing us to outline its state-of-the-art: by showing enzymes that have high activity and stability in extreme or poly-extreme conditions; understanding their relative adaptation mechanisms; reporting successful mining, designing, characterization, and production of novel extremophilic enzymes also by bioinformatic tools. We cover 15 manuscripts that explore different aspects of this Research Topic.