Characterization of Cold-Adapted Lipase from <i>Exiguobacterium</i> 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 <i>Exiguobacterium</i> species found in marine environments was cloned and expressed in <i>Escherichia coli</i> (<i>E. coli</i>). 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. Fe³⁺, Fe²⁺, and Ni²⁺ inhibited its activity, whereas Ca²⁺, K⁺, Na⁺, and Mg²⁺ enhanced it. Isooctane and <i>n</i>-heptane boosted activity; methanol and <i>n</i>-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.