Self-assembly of lipase hybrid nanoflowers with bifunctional Ca2+ for improved activity and stability.

Lipase ZC12, a cold-adapted lipase derived from Psychrobacter sp. ZY124, can be effectively activated by Ca2+. Inspired by this significant property, we developed a novel immobilized lipase ZC12/Ca3(PO4)2 hybrid nanoflowers (LHNs). The LHNs have been characterized as a regular hierarchical flowerlike structure nanoflowers by scanning electron microscopy (SEM). Compared with free lipase ZC12, the LHNs exerted enhanced enzymatic activity of 206% and 2.31-fold in kcat/Km value, especially high specific activity at low temperature. After 7 successive cycles, the LHNs could still maintain its initial activity, demonstrating superior durability than the free lipase ZC12. Meanwhile, its stability basically kept unchanged in a wide range of temperature and pH. Finally, fructose laurate was transformed by the LHNs with 57.39% conversion rate which is twice as much as the free lipase. To sum up, these results validated that LHNs could emerge as an efficient immobilized lipase and possess the promising potential for practical applications.