Fabrication of Cellulase Catalysts Immobilized on a Nanoscale Hybrid Polyaniline/Cationic Hydrogel Support for the Highly Efficient Catalytic Conversion of Cellulose

Abstract

A novel conductive nanohydrogel hybrid support was prepared by in situ polymerization of polyaniline nanorods on an electrospun cationic hydrogel of poly­(ε-caprolactone) and a cationic phosphine oxide macromolecule. Subsequently, the cellulase enzyme was immobilized on the hybrid support. Field-emission scanning electron microscopy and Brunauer–Emmett–Teller analyses confirmed a mesoporous, rod-like structure with a slit-like pore geometry for the immobilized support and exhibiting a high immobilization capacity and reduced diffusion resistance of the substrate. For comparison, the catalytic activity, storage stability, and reusability of the immobilized and free enzymes were evaluated. The results showed that the immobilized enzymes have higher thermal stability without changes in the optimal pH (5.5) and temperature (55 °C) for enzyme activity. A high immobilization efficiency (96%) was observed for the immobilized cellulose catalysts after optimization of parameters such as the pH, temperature, incubation time, and protein concentration. The immobilized enzyme retained almost 90% of its original activity after 4 weeks of storage and 73% of its original activity after the ninth reuse cycle. These results strongly suggest that the prepared hybrid support has the potential to be used as a support for protein immobilization.

Cellulase Immobilization on Nanostructured Supports for Biomass Waste Processing

“…This biocatalyst allows an enzymatic saccharification rate of 38.4% at 72 h, showing promise for deconstruction of lignocellulosic biomass. The same principle of cellulase immobilization using amino groups was utilized on a very different support: a hybrid conductive nanohydrogel prepared by polyaniline (PANI) nanorods formed on an electrospun cationic poly(ε-caprolactone) hydrogel containing cationic phosphine oxide macromolecule [ 72 ]. The hybrid nanobiocatalyst showed good performance in hydrolysis of cellulosic materials, exhibiting no loss of activity compared to free enzyme ( Figure 3 ).…”

“…It demonstrated high temperature tolerance, retaining 75% of activity at 80 °C as well as higher pH tolerance. A hybrid nanogel support where the PANI nanorods were formed in situ within nanogel prepared by electrospinning has been discussed in the section on the covalent attachment [ 72 ]. In this work, higher activity of the immobilized enzyme compared to the free enzyme was observed in the same temperature range, but the immobilized cellulase showed higher thermal and storage stability.…”

“… Hybrid cellulase-hydrogel nanobiocatalyst based on PANI nanorods formed on electrospun cationic poly(ε-caprolactone). Reproduced with permission from [ 72 ], Elsevier, 2022. …”

Facile Multilayer Deposition of Polyethylenimine and κ-Carrageenan on a 3D-Printed Lattice for Cellulase Immobilization

“…Nonetheless, similar rises in both K m and V max were also found in a previous study involving the immobilization of cellulase onto a polyaniline/ hydrogel electrospun support. 45 3.5. Saccharification of MCR.…”

Natural Glycyrrhizic Acid-Tailored Homogeneous Conductive Polyaniline Hydrogel as a Flexible Strain Sensor

“…Benefiting from the advantages of hydrogels and conductive polymers, polyaniline (PANi) hydrogels can present highly adjustable mechanical, electronic, and electrochemical properties, which have caught extensive attention in the fields of batteries, , supercapacitors, , catalysts, , and sensors. − At present, two main strategies are frequently used to fabricate PANi hydrogels. One is to directly blend PANi with the hydrogel, and the other one is to initiate in situ polymerization of aniline monomers predispersed in the hydrogel. − For the blending method, the PANi is first synthesized from aniline monomers promoted by proton acids like hydrochloric acid and phytic acid and then directly blends with gelators to form the conductive hydrogel.…”