In this study, chitosanase cloning from Streptomyces albolongus was fermented and purified by a Ni-NTA column. Fe₃O₄-SiO₂ magnetite nanoparticles (MNPs) were synthesized by the co-precipitation method coating with silica via a sol-gel reaction and were then amino functioned by treating with 3-aminopropyltriethoxysilane. Chitosanases were immobilized onto the surface of MNPs by covalent bonding (MNPs@chitosanase). Transmission electron microscopy (TEM), Fourier transform infrared spectrometer (FT–IR), and magnetic measurements were used to illustrate the MNPs and immobilized chitosanase. The optimal conditions of immobilization were studied. The thermal, pH, and stabilities of immobilized chitosanase were tested and the results showed that the stabilities were significantly enhanced compared with free chitosanase. After being recycled 10 times, the residual activity of the immobilized chitosanase was 43.7% of the initial activity.

This study presents a multilayer magnetic Janus sub-micrometric particle (MMJSP) as a nanoreactor for lipase catalysis. The core of the nanoparticle is constructed from a core-shell Fe₃O₄@SiO₂ framework, which serves as a precursor for the sequential amino and aldehyde modifications using 3-aminopropyltriethoxysilane and benzaldehyde. Following localized etching and subsequent modification with N,N-dimethyldodecylamine, a Janus nanoparticle with distinct hydrophilic and hydrophobic domains is synthesized. The resulting MMJSP demonstrates a stable attachment to the reaction interface and significantly enhances lipase performance, exhibiting 1.4-fold and 1.6-fold enhancements in activity after immobilization during 1 h hydrolysis and 24 h esterification reactions, respectively. Additionally, the storage stability of the immobilized lipase is improved by 100% over a period of 30 days. Reusability assessments reveal that the immobilized enzyme retains 80.7% activity after 10 cycles of esterification and 80.6% after 50 cycles of hydrolysis, with the magnetic properties allowing for rapid separation and recovery of the immobilized enzyme.