Poly(EGDMA/AAm) copolymer beads: a novel carrier for enzyme immobilization

Bilayer electrospun nanofibrous membrane: A matrix for lipase immobilization with high stability and reusability and its application on the synthesis of benzyl acetate

A cold-adapted recombinant lipase from the deep-sea psychrophilic bacterium Psychrobacter sp. C18 was purified and immobilized onto glutaraldehyde-activated bilayer nanofibers (BNFs) composed of polycaprolactone, chitosan, polyvinyl alcohol, and zinc oxide (PCL/Cs/PVA/ZnO), fabricated by electrospinning. The nanofibers were characterized using Scanning Electron Microscopy and Fourier Transform Infrared Spectroscopy, confirming their favorable morphology and chemical structure. Immobilization of Lipase C18 onto BNFs led to notable biochemical changes. While the free enzyme showed optimum activity at pH 8.0, the immobilized form shifted to ~pH 6.0, likely due to local microenvironmental effects. The immobilized lipase exhibited improved thermal and pH stability, enhanced storage durability, and better tolerance to mono- and divalent metal ions such as Na+, Fe2+, and Mg2+. Operational stability tests demonstrated that 91 % of enzymatic activity was retained after 20 reuse cycles. In transesterification reactions, the immobilized enzyme outperformed the free form, yielding more benzyl acetate, emphasizing its potential in fragrance and cosmetic industries. The bilayer nanofiber system provided superior performance over conventional immobilization supports, with the hydrophilic top layer enhancing wettability and the matrix structure improving enzyme functionality and robustness.

Pantoprazole-Na Release from Poly(acrylamide-co-crotonic acid) and Poly(acrylic acid-co-crotonic acid) Hydrogels

Poly(acrylamide-co-crotonic acid) (PAAmCA), poly(acrylic acid-co-crotonic acid) (PAACA), PAA and PAAm hydrogels were prepared by free radical polymerization and ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The variations of swelling values (%) with time, temperature, and pH were determined for four types of hydrogels. The PAACA hydrogel was swollen 2300% at pH = 7.4 and 37°C. The drug release from pantoprazole-Na loaded PAACA and PAAmCA hydrogels was followed at pH = 7.4, 37°C for 30 h. The release from PAACA hydrogel was faster than that from PAAmCA hydrogel; therapeutic levels for both hydrogels are obtained within 1 hour. Non-Fickian diffusion was determined for both hydrogels.