Synthesis of organic-inorganic hybrid nanoflowers of lipases from Candida antarctica type B (CALB) and Thermomyces lanuginosus (TLL): Improvement of thermal stability and reusability

Enzyme immobilization is used to improve the application of enzymes, allowing the reuse of biocatalysts and increasing their stability under reaction conditions. Immobilization of enzymes through structures, such as nanoflowers, is an innovative, simple, and low-cost method compared to other techniques. In this context, the main objective of this work is to synthesize hybrid biocatalytic nanostructures, similar to flowers, of lipases from Candida antarctica type B (CALB) and Thermomyces lanuginosus (TLL). The production of nanoflowers occurred by precipitation of lipases with CuCl2 or CuSO4 salts for 72 h. However, challenges and obstacles were faced in obtaining effective and practical nanoflowers, such as nanoflowers' low thermal stability and reusability. To overcome these challenges, two conditions were tested: nanoflowers cross-linked with glutaraldehyde and nanoflowers and nanoparticles cross-linked with glutaraldehyde. This last biocatalyst prepared by CuSO4 pre-cipitation showed better thermal stability (half-life about 230 and 233 min for CALB and TLL, respectively, under incubation at 60 degrees C and pH 7). The CALB biocatalyst retained 70 % of its initial activity (2.31 U) after 10 cycles of hydrolysis. Therefore, this work shows not only the problems and barriers of nanoflowers synthesis, but also the possibility of producing more stable and efficient biocatalysts using improved protocols.

Automated summary

Enzyme immobilization is a method to enhance enzyme application by allowing their reuse and improving stability. The immobilization of enzymes through nanoflowers structures is an innovative and cost-effective technique. This study aims to synthesize hybrid biocatalytic nanostructures similar to flowers using lipases from Candida antarctica type B (CALB) and Thermomyces lanuginosus (TLL). The production of nanoflowers was achieved through precipitation of lipases with CuCl2 or CuSO4 salts for 72 hours. However, challenges were faced in terms of low thermal stability and reusability. Glutaraldehyde cross-linking was tested to overcome these challenges, resulting in improved thermal stability and efficiency.