Abstract
The catalytic transformation (hydrolysis) of complex lignocellulosic polysaccharides into fermentable monosaccharides is crucial for producing bioethanol. Hydrolysis of various lignocellulosic biomasses can be achieved via traditional acid treatment (hydrochloric and sulfuric acid) and enzymatic catalysis. Considering the high specificity, selectivity, and prospective biocatalytic performance, enzyme biocatalysts are the preferred choice for an efficient and eco-friendlier deconstruction of lignocellulosic biomasses into simple fermentable sugars. Enzymes are a fascinating class of biodegradable catalysts that consume low energy and catalyze functioning under ambient environmental conditions. Recently, applying immobilized enzymes has emerged as a prodigious option in lignocellulosic biomass valorization. Immobilizing various enzymes, including cellulase, cellobiose, beta-glucosidase, laccase, and xylanase, on nano-support materials to constitute nanobiocatalyst has shown increased biocatalytic efficiency and stability. Furthermore, enzyme immobilization on magnetic nanomaterials promotes facile retrieval, separation, and recycling of biocatalysts. Consequently, the development and implementation of nanobiocatalytic systems offer an eco-friendly and cost-effective approach for the catalytic deconstruction of lignocellulosic biomass. This review article provides a comprehensive insight into contemporary developments and the application of nanomaterial-immobilized biocatalysts to catalyze the degradation of lignocellulosic biomasses. After a succinct overview of characteristics of key lignocellulosic biorefinery enzymes and immobilization techniques, and novel material supports, the application of nanomaterial-immobilized cellulase-based biocatalysts to catalyze the degradation and conversion of lignocellulosic biomasses is thoroughly vetted by compiling with state-of-the-art examples. Moreover, reactors for immobilized cellulase systems, major challenges, research gaps, and future endeavors are also directed. In conclusion, this study provides a new horizon to bridging the main knowledge gaps and explicit barriers of these bioprocesses to harnessing the full adventure of enzyme immobilization to realize sustainable biorefinery.