Review Articles

For about two millennia, paper has served as a main medium for preservation of people’s ideas, stories, contracts, and art.  This article reviews what is known about the various components that make up paper from the perspective of their long-term stability under typical storage conditions.  Literature evidence is considered relative to the susceptibility of different paper components to embrittlement, acid hydrolysis, microbiological attack, and discoloration, among others.  The cellulose that makes up a majority of most paper items is demonstrably stable enough to persist for many hundreds of years on the shelves of archival collections, though it is susceptible to acid-catalyzed hydrolysis, which can be accelerated by byproducts of decomposition.  Though less attention has been paid to the archival performance of various minor components of modern paper products, evidence suggests that at least some of them are subject to likely breakdown, embrittlement, or decay in the course of prolonged storage. Based on these considerations, one can envision different categories of paper that can be expected to meet different levels of storage stability: ancient recipes for handmade papermaking, e.g. washi and hanji, archival-grade paper products, ordinary modern alkaline paper products, and paper manufactured without concerns for its longevity.

Bamboo belongs to the grass family and is an important non-timber forest product in tropic and sub-tropic countries. The global trade of bamboo products is worth billions of dollars and is mainly dominant with monopodial bamboo grown in sub-tropic countries such as China and Japan. Many researchers globally discuss that in addition to species and region, bamboo quality can differ based on its rhizome types because the physiology is different for both monopodial and sympodial bamboo. However, there is a massive competition within the yearly forest products due to the challenges posed by underground root system in agroforestry. This review studied the properties of bamboo with regards to their differences in terms of monopodial and sympodial types of rhizomes. It was found that most of the structural, chemical organic, and mechanical properties are higher in monopodial bamboo, but there is a greater fibre morphology and decay resistance in the sympodial bamboo.

This review article discusses the use of organosilane (OS) compounds and their derivatives to modify wood materials. The emphasis in this work is on trialkoxysilanes and effects of their reactions with hydroxyl groups at wood surfaces. The versatile properties of OS make them ideal for improving the water resistance, weather resistance, antibacterial properties, and dimensional stability of wood. This article provides an overview of recent techniques and methods used to modify wood substrates with OS, highlighting the main findings and advancements in the field. Additionally, the article suggests future research directions, including innovative modification mechanisms, strategies to control the pollution caused by biomaterial-based silanes, and the investigation of the influence of wood permeability on silane modification.

Bamboo is a sustainable and cost-effective alternative to traditional construction materials. Despite the fact that three species are well known for structural applications, namely Dendrocalamus asper, Gigantochloa scortechinii, and Gigantochloa levis, the scientific data for their mechanical characterization is scarcely available and widely dispersed. In addition, a systematic literature review appraising the study advancement of mechanical characterization of bamboo had been unavailable. This paper bridges this gap by conducting a systematic literature review (SLR) of the available literature of mechanical characterization of bamboo pole. A total of 54 relevant articles were retrieved from Scopus and snowballing and then put forward through bibliometric analysis using VOSviewer. The results showed that the distribution of data for physical and mechanical characterization of aforementioned species was scattered due to the different location (origin), age, and initial moisture content recorded during empirical work among the researchers. This review’s importance and distinctiveness lie in its synthesis of the existing literature on bamboo mechanical characterization. The findings provide a point of reference for both academia and industry by bridging the scarcity of current bamboo engineering data and outlining future possibilities for bamboo research in the building and construction domain.

In recent decades, the scientific community has become interested in improving the extraction of bioactive compounds from plants through new extraction techniques. Microwave-assisted extraction (MAE) is an innovative and effective method to extract compounds from different plants of agronomic, medicinal, nutritional, or cosmetic interest. This technique is considered environmentally friendly, as it uses non-toxic solvents. In addition, its energy consumption is lower than conventional extraction techniques. Likewise, this extraction avoids the degradation of the compounds, making it a feasible method. For microwave extraction to be efficient, the following parameters must be considered: solvent characteristics, volume, exposure time, temperature, size and characteristics of plant material, power (MHz), and type of equipment. This review focuses on the interactions of various factors involved to achieve a successful extraction process. The optimization and importance of microwave extraction technology in the research of plant bioactive compounds are discussed in this review article.

Wood-based additive manufacturing (AM), some examples of which are called 3D printing, is a promising technology for reducing the environmental impact of manufacturing and increasing the sustainability of the construction industry. This review paper provides an overview of various AM methods, including commonly used wood-based techniques and the mechanical and physical properties of their products. The paper also discusses challenges related to precision and surface finish in wood-based AM and identifies areas for future research, including the effects of wood species, particle size, and processing parameters on the mechanical properties and dimensional stability of wood-based AM products. The review concludes by discussing the potential implications of wood-based AM for sustainable materials and the construction industry, along with recommendations for future research such as the development of new wood-based AM techniques and exploration of new applications for this technology. This paper provides valuable insights into the current state of wood-based AM research and its potential to revolutionize sustainable manufacturing practices.

The functionalization pattern in polysaccharide derivatives is an important factor that determines their properties and, thus, their functions in applications. Regioselectively functionalized polysaccharide derivatives are used in material science because they may form lamellar structures in microscale by self-assembling. Intrinsically chiral polysaccharide derivatives are used for the separation of enantiomers by chromatography, and the separation efficiency is influenced by the regioselective distribution of substituents attached. Due to the multi-functionality of polysaccharides, their derivatization reactions usually yield products with random distribution of substituents. Thus, establishment of unambiguous structure-property relationships cannot be achieved. This review article summarizes recent developments in this topic. In addition to the blocking group techniques, synthesis methods applying activating substituents will be summarized. Moreover, the reaction medium itself may direct the substituent in a certain position without laborious multistep reactions.

Wood is an indispensable renewable material for national economic development. As a bio-organic material, wood is subject to deterioration due to climatic, biological, and chemical factors, which greatly limit the advantages of wood products and increase the difficulty of conserving historical wood. To preserve the historical and cultural heritage, extend the historical life of ancient wooden structures, and promote the efficient and sustainable utilization of wood resources, this paper provides an overview of the main degradation and destruction forms and biochemical changes of wood in ancient architecture, unearthed relics, and antique ship wood from the perspective of wooden structure, historical applications, and their forms of destruction. The conservation strategies and consolidation methods of ancient wood are reviewed, with emphasis on the summary and analysis of the properties and uses of different consolidation materials and their methodological characteristics for the conservation of historical wood. In the context of the development of biomaterials, polymer chemistry and nanotechnology, biomass nanocomposites are applied gradually in the field of consolidation. To provide a strong basis for the effective use of reinforced wood, this paper presents the theoretical foundation for the research and development of green, efficient, and environmentally friendly wood consolidation and protection technologies.

Enzyme immobilization is a useful tool to produce biocatalysts with improved performance, such as high activity, high stability at operational conditions, and easy recovery and reuse.  In this context, the production of second-generation ethanol using immobilized enzymes was reviewed. Emphasis was placed on the pre-treatment and/or hydrolysis steps to increase efficiency and reduce the cost of the process. In addition, the process design of bioethanol using immobilized enzymes was critically reviewed. In the enzymatic pre-treatment, laccases, manganese peroxidases, lignin peroxidases, and lytic polysaccharide monooxygenases are the main enzymes involved. When considering processes with heterogeneous biocatalysts, laccases are the most explored enzyme. In the hydrolysis step, cellulases and hemicellulases or a mixture of them are the main enzymes explored in the literature frequently using magnetic nanoparticles as support for enzyme immobilization.  Although enzyme immobilization is a mature technology, the use of these biocatalysts is frequently limited to only one step of the bioethanol production process, such as pre-treatment or hydrolysis performed using Benchmark Technology. However, some recent papers have explored innovative design processes using a mixture of immobilized enzymes or co-immobilized enzymes to join some process steps, thereby decreasing the cost of enzymes and equipment.

Melanins are complex molecules found in many organisms including bacteria, fungi, plants, and animals that have protective functions against stress. In fungi there are several biochemical routes for their synthesis, and their diversity and structural complexity have made their analysis and characterization difficult. However, the possible specific functions of melanins in organisms have been determined. Based on their physicochemical properties, their potential in the application in various areas of interest and benefit of the human being have been visualized, such as in health and medicine, in bioremediation, and in the food industry. In this review, the type of melanins produced by fungi are discussed, as well as their main biological functions, the main biochemical routes involved in their synthesis, and potential applications in various areas. An important research area is visualized to find the best melanin-producing fungi as well as the conditions in which their production is maximized, in order to continue investigating the relationship of the structure of melanin with its biological functions as well as the determination of its physicochemical properties to establish its applications.