Attempts were made to enhance the hydrolysis of Asclepias syriaca (As) seed floss and poplar seed floss (PSF) by cellulase after pre-treatment with ionic liquids. Two ionic liquids, namely 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-ethyl-3-methylimidazolium tetrachloroaluminate [EMIM]Cl-AlCl3, were used. In comparison with conventional cellulose pretreatment processes, the ionic liquids were used under a milder condition corresponding to the optimum activity of cellulase. Hydrolysis kinetics of the IL-treated cellulose materials was significantly enhanced. The initial hydrolysis rates for IL-treated cellulose materials were greater than those of non-treated ones. The structural modifications of hydrolyzed cellulose materials were analyzed using FTIR spectroscopy.

Structural Changes in Wood under Artificial UV Light Irradiation Determined by FTIR Spectroscopy and Color Measurements – A Brief Review

Preservation of wood structures against degradation represents an old, and however, a new challenge. Wood, as a natural hybrid composite material, represents a versatile and widely exploited renewable resource for indoor and outdoor applications. Its constitutive biopolymers are subjected to intense and progressive oxidative degradation processes under environmental conditions of exposure, affecting wood’s native durability and generating significant structural and color changes, along with progressive diminution of its resistance against biological agents. One effective way to prevent wood degradation is to apply coating protective layers by chemical modification of the surface. In this context, increasing interest for improving wood coatings behavior under exposure to outdoor applications, when these are able to prevent or limit to a large extent the deleterious effects of environmental factors upon their performance, justifies enhanced research efforts to provide new effective solutions for sustainable wood protection. Recent trends in this area include use of bio-based natural products – extractives, oils, waxes, resins, biopolymers, biological control agents – for which the main classification criterion is represented by the type of protection provided, considering the large available variety of such formulations. The present paper focuses on the most recent literature data with significant assessment of specific topics related to these issues.

The study reported here presents a comparative screening of three medicinal plants including oregano (Origanum vulgare L.), lavender (Lavandula angustifolia) and lemon balm (Melissa officinalis) having the same geographical origin, the Southeast region of Romania, and growing in the same natural conditions. The contents of total phenolics and total flavonoids for the extracts of these were determined. Furthermore, the total antioxidant capacity was also evaluated. It was found that Origanum vulgare and Melissa officinalis extracts present the most effective antioxidant capacity in scavenging DPPH radicals, while Lavandula angustifolia is less active. High performance liquid chromatography–mass spectrometry analysis was used to identify the components of extracts. Major phenolic acids identified in the analysed species were ferulic, rosmarinic, p-coumaric and caffeic, while predominant flavonoids were quercetin, apigenin kaempherol, which were present as glucosides.

The crystallinity of cellulose substrates is a key factor in their processability, as well as an indication of their susceptibility to undergo sensitive reactions (such as enzymatic saccharification) with high yields. FT-IR and X-ray diffraction spectroscopy are useful, reliable, and easy-to-reach solid-state characterization methods for assessing the crystallinity of different cellulose substrates including wood and wood-based materials. Due to their specific methodology, they can be used to analyze not only starting materials and their final products but also intermediates. Data obtained by these methods substantiated the structural changes in cellulose substrates, as well as the alterations that occurred in their supramolecular architectures. The conversion of crystalline cellulose I into amorphous cellulose II during enzymatic saccharification, with or without pre-treatment (solubilization in ILs), was evidenced beyond any reasonable doubt by FT-IR and XRD experimental results. Enzyme hydrolysis rates of the ILs-treated cellulose substrates can be significantly increased, as evidenced by reducing sugar yields. Crystallinity index values for cellulose of different origins (initial, pre-treated with ILs, and hydrolyzed with enzyme, as well as cellulose submitted to one-pot procedure with ILs and enzyme) can be determined using FTIR and X-ray diffraction data and discussed for comparison purposes. The same solid-state characterization methods can be also successfully employed for investigation of surface changes, expressed as cellulose crystallinity, in wood samples before and after impregnation with natural-based products, as well as under biodegradation conditions in soil burial tests.