Review Articles

Enzymatic refining offers a sustainable alternative to mechanical refining for enhancing the quality of recycled paper fibers. This review examines (a) the benefits and limitations of enzymatic refining and (b) the most commonly used enzymes and their effectiveness. Studies from 2008 to 2023 were systematically analyzed using PRISMA screening to assess enzyme types, energy savings, and paper property improvements. Findings indicate that enzymatic refining reduces energy consumption by up to 20% while improving fiber bonding and drainage. Cellulases and hemicellulases are the most effective enzymes, enhancing mechanical strength and reducing water use. However, enzymatic refining alone is often insufficient, requiring additional mechanical refining for optimal results. Industrial adoption of enzymatic refining remains limited due to challenges in process integration and reaction optimization. This study highlights the role of this kind of refining in advancing circular economy goals and emphasizes future research needs, including enzyme formulation optimization and the development of scalable, one-step refining solutions.

The free drying shrinkage of wood is critical for dimensional stability and industrial applications. This study reviews the influencing factors (drying parameters, environmental conditions, and anatomical structures) and summarizes evaluation indexes and measurement methods. However, current research exhibits significant limitations. Systematic comparisons of free drying shrinkage between softwoods and hardwoods have been lacking, and the mechanism by which internal moisture variations affect shrinkage have remained unclear. Furthermore, existing techniques have failed to simultaneously measure moisture content changes and shrinkage with high accuracy. To address these gaps, future studies should: 1) investigate species-specific free drying shrinkage conditions; 2) elucidate moisture-induced shrinkage mechanisms from macro- and micro-scale perspectives; and 3) develop high-resolution methods for synchronous measurements. Further industrial applications of these findings could optimize wood drying processes and advance wood science and processing technologies.

This article reviews published literature related to the coating of wood surfaces for external applications. Research has shown that a wide range of procedural steps and components in coating formulations can contribute to increasing the effective service life of the coating as well as to maintaining the quality of the coated wood surfaces. Published findings support the idea that the commonly observed service life of painted wood surfaces exposed to outdoor weather can be significantly increased by dedicated application of such measures as optimized sanding, the use of an effective primary coat, the type of resin in the finish coat, increasing the number of layers of the finish coat, and a wide range of issues related to formulation of the finish coat. Even if a majority of contractors and homebuyers continue to prefer such options as vinyl or aluminum siding, the market opportunities remain very large for clients who prefer to rely on coatings and wood products for exterior surfaces of buildings and other exterior wood items.

Nanocellulose, a sustainable and versatile nanomaterial derived from abundant natural resources such as plants and bacteria, has emerged as a promising candidate for advancing eco-friendly food packaging. This review summarizes recent advancements in nanocellulose composites, focusing on their preparation methods, enhanced mechanical and barrier properties, applications in food preservation, safety profiles, and biodegradability. Nanocellulose composites, synthesized via techniques such as solution casting, melt intercalation, layer-by-layer self-assembly, in situ polymerization, coating, and ring-opening polymerization, can exhibit exceptional mechanical strength, oxygen and moisture barrier performance, as well as compatibility with active agents such as antioxidants and antimicrobials. Studies highlight the role of nanocellulose in reducing polymer composite permeability while maintaining biodegradability. Despite these advantages, challenges such as high production costs, energy-intensive methods (e.g., sulfuric acid hydrolysis), and hydrophilic limitations hinder industrial scalability. Emerging strategies, including enzymatic processing and surface modifications (acetylation, oxidation), offer pathways to enhance hydrophobicity, dispersion, and thermal stability. Future research should prioritize scalable, low-cost production technologies and expanded applications in smart and active packaging systems. By addressing these challenges, nanocellulose composites hold significant potential to revolutionize sustainable packaging, aligning with global demands for reduced environmental impact and enhanced food security.

Ruminant farming is a significant contributor to global food production but also a major source of methane emissions. It is responsible for nearly 44% of greenhouse gases from the agricultural sector. The integration of maize and lupine into the diets of ruminants offers a sustainable strategy for improving feed efficiency, reducing methane emissions, and enhancing animal productivity. Fermented maize silage has been shown to lower methane emissions by 10 to 20% compared to conventional high-starch diets. Lupine supplementation can further reduce methane emissions by influencing rumen fermentation. The inclusion of lupine, a nitrogen-fixing legume, additionally enhances soil fertility and reduces the need for synthetic fertilizers, making it an environmentally sustainable alternative to soybean meal. Studies indicate that diets incorporating maize silage and lupine can improve feed conversion efficiency and increase milk yield by up to 5% in dairy cattle. However, large-scale adoption of these feed additives requires further research to optimize fermentation processes, ensure economic feasibility, and overcome regulatory barriers. This study highlights the potential of maize and lupine as viable solutions for enhancing livestock sustainability while mitigating climate impacts.

Plant materials throughout the world, i.e. biomass, can provide annually roughly 18 x 10¹⁵ Watt-hours (6.5 x 10¹³ MJ) of energy, considering just the residues from agriculture and forestry. However, at least part of that amount has higher-valued uses, including being made into durable products, thereby keeping their carbon content from contributing to global warming. This review considers circumstances under which it may be advantageous to use biomass resources, either alone or in combination with other renewable energy technologies – such as solar and wind energy – to meet society’s energy needs, especially for electricity, heating, and transportation. There is a rapidly expanding pool of published research in this area. To slow climate change, rapid maturation of the most promising technologies is needed, followed by their widespread and early implementation. Of particular interest are synergistic combinations of technologies, including the use of solar energy and biomass together in such a way as to provide hydrogen, heating, and electricity. Another need is to use biomass to make high-energy-density liquid fuels, including aviation fuels, diesel, and naphtha. Although some proposed schemes are complicated, biomass is expected to be gradually implemented as a growing component of installed renewable energy capacity in the coming years.