Characterisation, Recovery and Activity of Hydrophobic Compounds in Norway Spruce Log Soaking Pit Water: Could they be Used in Wood Preservative Formulations?

Purpose Norway spruce log soaking water (SLSW) is considered a waste in the plywood and veneer industry but has not been characterised, and its possible uses remain unexplored. The purpose of this study is to characterise and test the possibility of using SLSW in wood preservative formulations. Methods First, the SLSW was characterised, and the presence of carbohydrates in the log soaking water was reduced with a hydrophobic adsorbent to reduce the nutrient availability for fungi in the liquids. Then, the feasibility of using SLSW and the sugar free SLSW (denoted later as EHC solution) as wood preservatives was studied by testing their antifungal and antioxidant activities and performing a mini-block test against Schizophyllum commune, Trametes versicolor, Fibroporia vaillantii and Gloeophyllum trabeum. Results Several phenolic compounds were found in the SLSW. This water also had high antioxidant activity at 1000 mg/L before and after carbohydrate removal but no antifungal activity. Its impregnation in wood caused a slight reduction in mass loss of the Pinus sylvestris specimens but had no effect on the Fagus sylvatica specimens when exposed against Schizophyllum commune, Trametes versicolor, Fibroporia vaillantii and Gloeophyllum trabeum. Conclusion The SLSW as a wood preservative is invalid, even after partial carbohydrate removal. However, due to the presence of wood constituents, SLSW could be a resource for other uses requiring high antioxidant activity but specific applications need further investigation. Graphical Abstract

Encapsulation of agrichemicals by renewable cellulosic derivatives

<p>Cellulose derivatives, charged with fungicides, have been prepared as particles for use as a wood preservative. The particles were designed to encapsulate the current industry-standard chemical agents used to minimise wood degrading fungal action and to deter termites. A detailed study on the most effective methodology that would be suitable for scaled-up production was undertaken. The methods explored included: double emulsions, solvent diffusion by dialysis membrane and phase inversion emulsification. Particles formed by these methods were characterised by scanning electron microscopy, dynamic light scattering, nuclear magnetic resonance spectroscopy and infrared spectroscopy. The fungicide incorporation was confirmed by nuclear magnetic resonance studies and gas-chromatography analytical analysis. The phase inversion emulsion process was found to be highly effective and readily manipulated to modify particle formation. Particles were successfully prepared containing fungicides in a yield of 35-75% (method dependant), containing the biocide at approximately 50% mass of biocide to total particle mass. Thus, this process was optimised through modifying the addition time of the aqueous phase, as well as variation of the surfactant and salt concentrations. With an optimised particle forming method, three fungicides were incorporated into the formulation and subsequently analysed to demonstrate successful biocide incorporation. The biocide charged mesoparticles underwent testing for antifungal action by our industrial partners Lonza.</p>

Encapsulation of agrichemicals by renewable cellulosic derivatives

<p>Cellulose derivatives, charged with fungicides, have been prepared as particles for use as a wood preservative. The particles were designed to encapsulate the current industry-standard chemical agents used to minimise wood degrading fungal action and to deter termites. A detailed study on the most effective methodology that would be suitable for scaled-up production was undertaken. The methods explored included: double emulsions, solvent diffusion by dialysis membrane and phase inversion emulsification. Particles formed by these methods were characterised by scanning electron microscopy, dynamic light scattering, nuclear magnetic resonance spectroscopy and infrared spectroscopy. The fungicide incorporation was confirmed by nuclear magnetic resonance studies and gas-chromatography analytical analysis. The phase inversion emulsion process was found to be highly effective and readily manipulated to modify particle formation. Particles were successfully prepared containing fungicides in a yield of 35-75% (method dependant), containing the biocide at approximately 50% mass of biocide to total particle mass. Thus, this process was optimised through modifying the addition time of the aqueous phase, as well as variation of the surfactant and salt concentrations. With an optimised particle forming method, three fungicides were incorporated into the formulation and subsequently analysed to demonstrate successful biocide incorporation. The biocide charged mesoparticles underwent testing for antifungal action by our industrial partners Lonza.</p>

Diallyl Trisulfide, the Antifungal Component of Garlic Essential Oil and the Bioactivity of Its Nanoemulsions Formed by Spontaneous Emulsification

The aim of this study was to evaluate the chemical compounds of garlic essential oil (EO), and determine the antifungal efficacy of garlic EO and its major components, diallyl trisulfide and its nanoemulsions against wood-rotting fungi, Trametes hirsuta and Laetiporus sulphureus. GC-MS analysis revealed that the major constituents of garlic EO were diallyl trisulfide (39.79%), diallyl disulfide (32.91%), and diallyl sulfide (7.02%). In antifungal activity, the IC50 value of garlic EO against T. hirsuta and L. sulphureus were 137.3 and 44.6 μg/mL, respectively. Results from the antifungal tests demonstrated that the three major constituents were shown to have good antifungal activity, in which, diallyl trisulfide was the most effective against T. hirsuta and L. sulphureus, with the IC50 values of 56.1 and 31.6 μg/mL, respectively. The diallyl trisulfide nanoemulsions showed high antifungal efficacy against the examined wood-rotting fungi, and as the amount of diallyl trisulfide in the lipid phase increases, the antifungal efficacy of the nanoemulsions increases. These results showed that the nanoemulsions and normal emulsion of diallyl trisulfide have potential to develop into a natural wood preservative.

Parthenium hysterophorus: Weed of Pharmacological Importance

Parthenium hysterophorus, often known as congers grass, is a noxious weed that is a member of the Asteraceae family of plants. Its natural habitats include the areas surrounding the Gulf of Mexico, Central America, Southern North America, the West Indies, and Central South America, among other places. Congress grass has risen to become one of the world’s seven most destructive and deadly weeds, according to the World Health Organization. This invasive plant is also a significant concern in India. It is responsible for a variety of illnesses and allergies in both people and animals. Aside from that, there is some potential for this plant to be used as an insecticide, herbicide, fungicide, wood preservative, anti-amoebic, and even for medicinal purposes. If any species, particularly an invasive weed, is to be evaluated for its ability to benefit living organisms, it is necessary to have a thorough understanding of both its positive and negative impacts. As a result, this review paper is an attempt to describe the present state of knowledge regarding the hazardous and helpful effects of Parthenium hysterophorus on people and animals.

Study of Antifungal Activity Using Three Chinese Medicine Herbs

Chinese medicine herbal extracts are ideal candidates to replace toxic industrial wood preservatives thanks to their antifungal and nontoxic properties. To investigate the antifungal activity of Chinese herbal medicines, in this study, Trametes versicolor fungi were selected as test strains to evaluate the antifungal properties of Fructus Cnidii, Fructus Forsythiae, and Radix Stemonae. The results show that Fructus Cnidii has a strong inhibitory effect against T. versicolor, whereas Fructus Forsythiae and Radix Stemonae have a weak inhibitory effect. The hyphae growth cycle shows that the three studied Chinese herbs disrupt the growth of T. versicolor. Moreover, instead of direct killing, the Chinese herbal medicine demonstrated inhibition ability. Furthermore, the morphological and toxicological evidence shows that Fructus Cnidii affected the expression of proteins or enzymes to achieve the inhibition goal. In sum, this study could provide both primary data and a theoretical foundation for further developing and applying for traditional Chinese medicine as a green type of wood preservative.

Combination of nano-CuO/silica sol preservative with various post-treatments to improve the compressive strength, water resistance, and thermal stability of wood

A nano-CuO/silica sol wood preservative was obtained by dispersing CuO nanoparticles in propylene glycol and silica sol. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, thermogravimetric analysis, and compressive tests were conducted to investigate the effects of different post-treatments, i.e., steaming at 100 °C and freezing at -30 °C, on the variations in microstructure, mechanical, physical, and thermal stability properties of the preservative-impregnated wood. The results revealed that the mechanical properties, water resistance, and thermal stability of the impregnated specimens were greatly ameliorated. The steaming treatment resulted in a more uniform and dense distribution of the preservative in the blocks. The steaming treatment performed better in terms of enhancing the compressive strength of the specimens, while the freezing treatment was more effective in improving the thermal stability of the specimens. Both the steaming and freezing treatments can considerably improve the water resistance of the specimens. The different post-treatments retain the basic properties of the wood; however, they differ in the improved wood properties and provide a basis for their selection in the industrial production of nano-preservatives.

Enhancement of Wood Biological Resistance and Fire Retardant Properties after Laccase Assisted Enzymatic Grafting

Several treatments of wood, based on laccase assisted grafting, were evaluated in this paper. Firstly, the efficacy of lignosulfonate and kraft lignin from Eucalyptus spp. as a wood preservative was assessed. Both ligno products were anchored to wood surfaces via laccase treatment in order to avoid leaching. Moreover, some of these wood preservative treatments were completed with the addition of silver nanoparticles. For comparison, a commercial product was also analyzed in terms of its fungal decay resistance during surface application, in accordance to use class 3, CEN EN 335. Secondly, the anchoring of a flame retardant based on tetrabromobisphenol-A (TBBPA) was attempted, to limit the dispersion of this toxic substance from treated wood. In both cases, kraft lignin and lignosulfonate showed an improvement in wood durability, even after leaching. However, the addition of silver nanoparticles did not improve the efficacy. On the other hand, the efficacy of TBBPA as a flame retardant was not improved by grafting it with laccase treatment or by adding O2, a co-factor of laccase.