International Journal of Biological Macromolecules 209 (2022) 1048–1053 Available online 18 April 2022 0141-8130/© 2022 Published by Elsevier B.V. Magnetic nickel nanostructure as cellulase immobilization surface for the hydrolysis of lignocellulosic biomass Shah Samiur Rashid a, *, 1 , Abu Hasnat Mustafa a, 1 , Mohd Hasbi Ab Rahim a , Burcu Gunes b a Faculty of Industrial Sciences and Technology, Universiti Malaysia Pahang, Lebuh Raya Tun Razak, 26300 Gambang, Pahang, Malaysia b School of Biotechnology and DCU Water Institute, Dublin City University, Glasnevin, Dublin 9, Ireland A R T I C L E INFO Keywords: Nickel nanoparticles Amino functionalization Cellulase immobilization Enzymatic hydrolysis Enzyme reusability ABSTRACT In this research, a magnetic reusable nickel nanoparticle (NiNPs) supporting materials were prepared for cellulase enzyme immobilization. The immobilized cellulase showed high activity recovery, large & fast immobilization capacity and improved pH & temperature tolerance. The excellent stability and reusability enabled the immobilized cellulase to retain 84% of its initial activity after ten cycles. At 2 mg/mL enzyme concentration, highest 93% immobilization effciency was achieved within two hours of immobilization. When the treatment temperature reached 40 ◦ C and pH 5, the immobilized cellulase exhibited highest residual activity. The immobilized cellulase could be separated from the solution by a magnetic force. This study introduced a novel supporting material for cellulase immobilization, and the immobilized cellulase poses a great potential in the hydrolysis of lignocellulosic biomass which can used as an easily applicable and sustainable pre-treatment step for advanced biofuel production. 1. Introduction Over the last decade on the wake of fossil fuel concerns, cellulosic enzyme as an alternative green operation condition draws special attention to the production of biofuels such as biodiesel, bioethanol, bio- hydrogen, and biogas through lignocellulosic biomass conversion. A complete hydrolysis of cellulose for the biomass conversion is an essential step in the process for achieving high biofuel conversion yields. Cellulase hydrolyze cellulose which is one of the most abundant natural and renewable biopolymers. However, the widespread applications of cellulase are considered to be non-feasible and un-sustainable due to the operational stability, recovery, and reusability [1,2]. Immobilizing enzyme onto magnetic nanoparticles to separate them via external magnetic force has been attracting a great research interest for its industrial and commercial applications. Unlike fltration and centrifugation, magnetic separation of enzyme is easy, cost effective and effcient in preventing enzyme loss [3]. Cellulase immobilization onto magnetic nanoparticle also improve enzyme reusability and its thermal & pH stability [3,4]. Among the magnetic nanoparticles, iron oxide nanoparticles have been tested for enzyme immobilization [4–8]. However, iron nanoparticles are prompt to atmospheric air oxidation and agglomera- tion [9], also diffcult to control the size and have relatively weak magnetism and crystallization [10]. Iron based catalyst have a high leaching and turbidity due to oxidation that can cause disruption during colorimetric assays [11]. Besides, this process requires a sequential so- phisticated synthesizing approach. Additionally, adoption of a heavy surface modifcation with closed nitrogenous system is required to control the particles oxidation and aggregation at room temperature [5,6]. Thus, an alternative magnetic supporting material is required to overcome these challenges. Nickel nanoparticles (NiNPs) are used in biosensors [12], energy storage [13] and photocatalytic application [14]. NiNPs have different unique characteristics like high magnetism that can be easily separated with external magnetic force, high surface area can provide higher immobilization effciencies, high level of surface energy, low burning point and low melting point [15]. Nickel is one of the few ferromagnetic materials and its application for lignocellulosic enzyme immobilization on the nickel nanoparticles yet to report. In this current investigation, cellulase enzyme was immobilized onto magnetic nickel nanoparticles for the hydrolysis of cellulose contained in the lignocellulosic biomass. Surface area of any solid support needs to be functionalized * Corresponding author. E-mail address: samiur@ump.edu.my (S.S. Rashid). 1 Both authors contributed equally and shared the frst author position. Contents lists available at ScienceDirect International Journal of Biological Macromolecules journal homepage: www.elsevier.com/locate/ijbiomac https://doi.org/10.1016/j.ijbiomac.2022.04.072 Received 26 November 2021; Received in revised form 8 April 2022; Accepted 9 April 2022