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. Fe3+, Fe2+, and Ni2+ inhibited its activity, whereas Ca2+, K+, Na+, and Mg2+ 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.