Charge-Tunable μ-Gelzymes Achieving Cellulose Affinity under Synergistic Ionic Liquid-Pretreated Biomass in Situ Saccharification

Abstract

Enzyme-loaded microgels (μ-Gelzymes) have gained increasing attention for their facile fabrication, versatile applicability, and fine controllability. Herein, a series of poly(N-isopropylacrylamide) (PNIPAM)-based μ-Gelzymes (P-C) with a tunable surface potential were prepared to improve the cellulase biocatalytic effect. The P-C showed better cellulose affinity than free cellulase, highly reducing its nonproductive binding onto lignin, while the Langmuir adsorption affinity indexes (K) of P-C for cellulose and lignin were 1.19 and 0.34 g/L, whereas those of free cellulase were 0.44 and 3.92 g/L, respectively. Moreover, the biomass synergistic pretreatment with 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) and choline acetate ([Ch]OAc) resulted in an almost equal ζ-potential on lignin, cellulose, and hemicellulose. Microcrystalline cellulose (MCC) and bagasse (BC) substrate conversions achieved by P-C were 19.8 and 12.1% higher than those with free cellulase under 3% [Ch]OAc + 7% [EMIM]OAc in situ saccharification. The P-C ζ-potential and biomass glucose production demonstrated that the more the electroneutrality on P-C, the higher the glucose generation, suggesting that biomass saccharification can be controlled by adjusting the surface charge on μ-Gelzymes.

Ionozymes for Efficient Synthesis of Cadaverine: Offering a Sustainable Way for Bio-nylon 5X Production

“…In addition, the binary ILs–solvent systems demonstrate a great synergetic effect favoring the improvement of catalytic efficiency, and the IL–IL synergetic systems also have been reported to regulate the substrate affinity and improve the activity and stability of enzymes. , Therefore, synergetic systems combining imidazolium-based ILs and choline-based ILs ([Emim]­Cl-[Ch]­[Ser] and [Emim]­Cl-[Ch]­[H 2 PO 4 ]) have been first applied into the catalytic process. Meanwhile, the synergetic system formed by 0.005% (w/v) [Emim]­Cl-0.005% (w/v) [Ch]­[Ser] could improve the catalytic activity of ΔLdcEt3 to 123.8% ± 5.0, while the 0.01% (w/v) [Emim]­Cl-[Ch]­[Ser] synergic system expressed an inhibited effect on the ΔLdcEt3 (Figure S41).…”

“…41,42 In addition, some imidazolium-based ILs with short side chains owned preferable bioactivity in favor of the stability of protein. 43 In In addition, the binary ILs−solvent systems demonstrate a great synergetic effect favoring the improvement of catalytic efficiency, 45 and the IL−IL synergetic systems also have been reported to regulate the substrate affinity 20 and improve the activity and stability of enzymes. 31,46 Structural Changes and Aggregation of Ionozymes ΔLdcEt3-ILs.…”

“…The preferable microenvironment for enzymatic reactions can affect catalytic properties obviously. − Ionic liquids (ILs), a tunable solvent or cosolvent with favorable biocompatibility, have been proved to have distinct process intensification effects on enzymatic catalysis, − which has been widely applied in lipase-catalyzed transesterification to activate the enzymatic reaction and achieved good catalytic results. − In these ionic microenvironments, ILs could create the local microenvironment around the protein surface and affect the appearance of intermediate production to enhance enzymatic activity and stability. − Currently, the third-generation ILs with low biotoxicity, biocompatibility, and biodegradability have been designed and synthesized for specific enzymatic reactions. − Xue et al designed and synthesized varieties of betaine ILs to modify Candida antarctica lipase B (CALB), and the addition of ILs improved the catalytic activity and the structural stability by 3 times and 1.5 times, respectively. Liu et al explored a bi-enzyme system (aryl alcohol oxidase and lignin peroxidase) to depolymerized lignin in the biocompatible IL system.…”