Characterization of Cold-Adapted Lipase from Exiguobacterium sp. and Its Cold Adaptation Mechanism

Cold-adapted lipase has a wide range of applications in the fields of food, detergent, and pharmaceuticals. In this study, a low-temperature alkaline lipase gene EaLIP27 from an Exiguobacterium species found in marine environments was cloned and expressed in Escherichia coli ( E. coli ). The purified recombinant enzyme, weighing 27 kDa, showed significant activity at 337.2 U/mg. Optimal performance occurred at 35 °C and pH 8.0, retaining 43% activity even at 15 °C. It displayed broad pH stability and variable responses to metal ions and organic solvents. Fe 3+, Fe 2+, and Ni 2+ inhibited its activity, whereas Ca 2+, K +, Na +, and Mg 2+ enhanced it. Isooctane and n -heptane boosted activity; methanol and n -butanol had inhibitory effects. Notably, EaLIP27 exhibited strong resistance to most organic solvents and minimal surfactant concentrations, indicating the potential for use in detergents. Analysis revealed a high proportion of α-helices and Gly, with a relatively loose structure, contributing to its cold-adapted structure. This study discovered novel and enzymatically excellent low-temperature lipases and provided new insights into cold adaptation mechanisms from a molecular structure perspective.