Hybrid soft biomaterial of wool keratin and graphene oxide for immobilization of thermophilic and halophilic dehydrogenase from extremophile

Wool keratin (WK) obtained from waste wool, is a flexible material and with excellent properties such as good biocompatibility and easy modification. Hybrid material combined of WK with graphene oxide (GO) was applied for the immobilization of thermophilic and halophilic phenylalanine dehydrogenase from Natranaerobius thermophiles (NT) which is separated from marine. Graphene oxide assembles with WK-NT and formed layer by layer sandwich structure, through multi-level interactions such as hydrogen bonds and electrostatic interactions. Immobilized enzyme (GO-WK-NT) was applied for L-Homophenylalanine (L-HPA) biosynthesis. Activity of GO-WK-NT was enhanced by 1.42-fold compared to that of free enzyme. After 5 times reuse, GO-WK-NT retained 73.46% relative activity. The immobilized enzyme has enhanced thermostability and improved organic solvent tolerance than the free enzyme. Incubating in 70 ℃ and pH 9.0 for 2.5 h, GO-WK-NT retained 69.4% relative activity. Enhanced catalyzed efficiency of GO-WK-NT is with a kcat/Km of 3.32 s− 1·mM− 1. This work offers a value added approach of waste wool and provide promising industrial applications for green biosynthesis of L-homophenylalanine (L-HPA) as well as demonstrates excellent potential in enzyme electrode systems for biosensing applications and wearable healthcare technologies.