Aug 2026· International Journal of Biological Macromolecules· Vol 381, pp.
154163
· 0 citations· 158 references
Medicine
TL;DR
This review frames cellulosome engineering as a process-aware macromolecular assembly problem, in which catalytic balance, substrate targeting, assembly size, inter-domain spacing, and environmental robustness must be optimized together.
Abstract
Lignocellulosic biomass is a heterogeneous solid matrix whose biological deconstruction is limited by cellulose accessibility, lignin exposure, pore-scale transport, and enzyme stability at solid-liquid interfaces. Although bacterial cellulosomes provide a natural strategy for organizing multiple enzymes through scaffoldin-mediated cohesin-dockerin interactions, their engineering value depends on more than enzyme colocalization. This review frames cellulosome engineering as a process-aware macromolecular assembly problem, in which catalytic balance, substrate targeting, assembly size, inter-domain spacing, and environmental robustness must be optimized together. Natural cellulosome architecture is discussed in terms of its roles in enzyme recruitment and catalytic synergy. In addition, cellulosomal systems are compared with industrial fungal enzyme cocktails regarding production, scalability, and substrate accessibility. Rather than viewing engineered cellulosomes as universally superior multienzyme complexes, we evaluate how their performance is constrained by lignin adsorption, steric exclusion, diffusion limitations, high-solids conditions, host burden, catalyst recovery, AI-guided design validation, and the mismatch between model substrates and industrial feedstocks. Future progress will require experimentally validated, substrate-specific, and process-compatible cellulosome designs that balance catalytic diversity with assembly stability, production feasibility, and techno-economic performance.
The sustainable bioeconomy fundamentally relies on the effective valorization of lignocellulosic biomass into renewable fuels and high-value biochemicals. Although extensive research has been conducted over several decades, commercialization remains hindered by enzyme instability, low catalytic efficiency, high production costs, and the intrinsic recalcitrance of biomass. While previous reviews have separately discussed lignocellulolytic enzymes, biomass conversion, or circular bioeconomy strategies, comprehensive integration of recent molecular, microbial, and process-engineering advancements remains limited. Therefore, this review provides a multidisciplinary perspective integrating enzyme engineering, microbial co-culturing, heterologous gene expression, advanced biomass pretreatment, and bioprocess optimization within a unified biorefinery framework. The review critically links molecular-level improvements, including protein engineering, codon optimization, and thermostability enhancement, with industrial process strategies such as consolidated bioprocessing, consolidated bio-saccharification, and techno-economic optimization. Emerging approaches including CRISPR/Cas9-mediated strain improvement, artificial cellulosomes, nanobiotechnology, and AI-assisted modeling are discussed as supportive tools for improving biomass conversion efficiency and industrial applicability. In addition, major bottlenecks such as enzyme instability, biomass recalcitrance, and process incompatibilities are critically evaluated along with recent strategies to overcome these limitations. By integrating molecular biology, microbial engineering, and process-level innovations, this review provides a comprehensive framework for the development of sustainable and scalable lignocellulosic biorefineries supporting the circular bioeconomy.
This review focuses on cellulase production as a platform for biotechnology rather than as a standalone fermentation process and connects native cellulase-producing microorganisms, omics-guided enzyme discovery, lignocellulosic substrate selection, pretreatment and inhibitor tolerance, solid-state and submerged fermentation, enzyme engineering, downstream recovery, immobilization, reusability and industrial translation.
H. Rahat, Duaa Qaiser, Quratulain Maqsood et al.· Biotechnology and Bioenginee...· 0 citations
Mechanical force offers a distinctive nonequilibrium mode of energy input for lignocellulosic biomass valorization through localized, transient action. This review systematically examines the multiscale physicochemical effects of mechanical force, its synergistic coupling with chemical pretreatments, and its role in enhancing enzymatic hydrolysis. The principal contribution of mechanical force is not merely particle-size reduction, but the exposure of active sites and improvement in substrate accessibility at the molecular level. Coupling mechanical force with chemical pretreatment enables the efficient component fractionation under mild conditions while mitigating irreversible lignin condensation. In high-solids enzymatic hydrolysis, a periodic mechanical energy input can tear fiber bundles, release constrained water, and renew reaction interfaces, thereby allowing enzymes to sustain a high catalytic efficiency at extremely low liquid-to-solid ratios and reducing the dependence on large amounts of free water. An economic analysis indicates that feedstock and enzyme costs dominate the overall process economics. Accordingly, mechanical-force strategies should prioritize the maximized sugar yield and reduced enzyme loading under a controlled energy input. Future research should focus on continuous operation, the balance between mechanical deconstruction and lignin structural integrity, and multidimensional evaluation frameworks that integrate the energy consumption, sugar yield, enzyme dosage, and full-process energy balance.
Bo Feng, Si-Yu Chen, Qianyi Shangguan et al.· Agriculture· 0 citations
Starch-based bioplastics are renewable and biodegradable, but their wider use is constrained by moisture sorption, humidity-dependent aging, insufficient tensile performance, and weak water- and oxygen barrier stability. This review critically synthesizes the peer-reviewed literature from 2020 to 2026 on enzymatically engineered starch for film, packaging, and thermoplastic applications using an architecture–property framework that links enzyme specificity, chain-length distribution, crystallinity, processing route, and material response. Controlled α-1,4 hydrolysis mainly improves processability by lowering molecular weight, viscosity, and gelatinization resistance. However, excessive hydrolysis can increase water uptake, solubility, and loss of cohesive strength. Debranching by pullulanase or isoamylase increases amylose-like linear chains and can promote B-type crystallinity or V-type starch–lipid complexes, with reported gains in tensile strength, contact angle, and water vapor barrier when the chain lengths and recrystallization conditions are controlled. Branching enzymes and transglycosylases increase branch density or redistribute glucan chains, suppressing retrogradation and improving flexibility, water retention, and aging resistance, but often with trade-offs in strength, crystallinity, and barrier performance. Lipase- and laccase-catalyzed functionalization expands starch functionality by increasing hydrophobicity, compatibility with hydrophobic phases, antioxidant activity, and active-packaging potential. The evidence indicates that enzymatic modification should not be generalized as uniformly improving starch bioplastics; performance gains are conditional on the starch source, amylose content, enzyme dosage, reaction severity, plasticizer composition, processing method, film conditioning, and storage humidity. Industrial implementation remains limited by enzyme cost and reuse, high-solids mass transfer, reaction time, enzyme stability under heat and shear, and reproducibility across botanical sources. Overall, enzymatic molecular editing is most promising when mechanistic architecture control is coupled with standardized structure–property reporting and scalable processing, such as immobilized-enzyme reactors, high-solids systems, and reactive extrusion.
Maria Eduarda Costa, A. Sarinho, Janaina M. Lima et al.· Macromol· 0 citations
Lignin is one of the abundant aromatic biopolymers in nature, constituting approximately 15–30% of the lignocellulosic biomass and representing a major renewable source of aromatic carbon. Its high carbon content, high thermal stability, biodegradability, antioxidant property, and ability to absorb ultraviolet radiation make lignin an attractive precursor for many potential applications, such as for renewable carbon materials, plastics, additives, surfactants, and the resin industry. However, its large-scale valorisation remains limited due to its complex, heterogeneous structure and the limited ability of experimental techniques to resolve its molecular architecture and reaction mechanisms. Recent advancements in computer-based simulations, especially molecular dynamics (MD) and density functional theory (DFT), offer powerful tools to overcome these limitations by enabling molecular and atomic-level insight into lignin structure, properties, and transformation processes. These methods provide detailed insights into lignin reactivity, thermophysical behaviour, self-assembly, and catalytic depolymerisation that are often difficult to obtain experimentally. This review summarises recent advances in computational studies of lignin and its derivatives, highlighting how different modelling approaches have been used to investigate the various physicochemical properties and reaction mechanisms. In addition, the limitations and challenges associated with current modelling strategies are discussed, and future research directions, including multiscale modelling and machine-learning-based approaches, are outlined. Overall, this review aims to provide a comprehensive overview of how computational methods advance lignin research and support the development of sustainable lignin-based materials.
Raju Kumar, Igor Zozoulenko, Aleksandar Y. Mehandzhiyski· RSC Advances· 0 citations
Reductive catalytic fractionation (RCF) has emerged as a representative lignin-first biorefining strategy for converting native lignin into aromatic monomers while preserving a carbohydrate-rich pulp for subsequent valorization. Although previous reviews have summarized the effects of feedstocks, solvents, and catalysts on monomer production, a process-oriented synthesis that connects reaction chemistry with reactor configuration, solvent recycling, catalyst recovery, and scale-up remains limited. This review, therefore, reassesses recent advances in RCF from an integrated process perspective. The comparative analysis indicates that monomer yield cannot be predicted by lignin content alone but is governed by the combined effects of β-O-4 abundance, lignin condensation, S/G ratio, lignin-carbohydrate connectivity, tissue structure, and solvent accessibility. Solvent systems are further evaluated not only by their ability to promote lignin extraction and intermediate stabilization, but also by their influence on carbohydrate retention, solvent recovery, and process sustainability. Catalyst development is discussed in relation to metal–support interactions, hydrogen-transfer pathways, catalyst placement, deactivation resistance, and compatibility with recycled solvents. Particular emphasis is placed on the transition from batch screening to semi-continuous, flow-through, and continuous-flow RCF, where spatial separation of lignin extraction and catalytic stabilization can improve residence-time control, mass transfer, catalyst recovery, and process scalability. The analysis further indicates that high-pressure batch reactors remain useful for laboratory screening, but their direct industrial implementation is restricted by equipment cost, safety requirements, energy input, high solvent-to-biomass ratios, and solvent recovery burden. Flow-through and continuous-flow configurations, coupled with solvent-loop optimization and catalyst recovery, are, therefore, more promising for scalable RCF. Finally, techno-economic analysis, life-cycle assessment, solvent-loop design, lignin-oil upgrading, and standardized reporting requirements are discussed as essential criteria for industrial implementation. Overall, this review highlights that scalable RCF should not be regarded simply as an optimized depolymerization reaction, but as a reactor- and recycle-aware lignin-first process architecture that integrates feedstock selection, solvent-catalyst chemistry, separation strategy, catalyst lifetime, solvent recovery, and downstream utilization.
