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Wood-feeding termites and wood-decaying fungi share a niche and likely interact, impacting wood degradation processes. Prior research has primarily examined termite the preferences for decayed wood species, revealing instances of termite feeding deterrence in response to fungal decay products. The compound that caused the deterrence effect was extracted and studies regarding the suspected compound and its toxicity has been previously conducted. In this study, further observation of the extract retention and concentrations were asessed against Reticulitermes speratus. Result indicated that the decayed wood extract retains its deterrent activity for up to four days post-application, with a peak effect observed within the initial hours. Furthermore, the concentration of the extract correlates with both feeding deterrence and termite mortality, suggesting a concentration-dependent relationship. Results show a significant decrease in feeding and increase in mortality with longer exposure durations, indicating sustained deterrent activity for up to four days. Higher extract volumes correlate with reduced feeding and increased mortality, supporting concentration-dependent deterrence. Highest mortality was observed after 24 hours of exposure, suggesting continued toxicity despite diminished deterrence.

Tannins are capable of producing natural dyes with antioxidant and antibacterial propertis, while synthetic dyes are commonly used in the textile industry, causing environmental issues like water pollution. This research aims to utilize waste tannins as natural dyes as an alternative to synthetic dyes. This study examined the effect of the extraction method on tannin properties such as phenolic content, antioxidants, and antibacterial activity. In addition, Pyrolysis Gas Chromatography‒Mass Spectrometry (Py-GCMS) analysis was used to identify the effect of extraction temperature on the chemical elucidation of tannin. The effect of tannin concentration was evaluated against four bacteria that are usually found on human skin: Staphylococcus epidermidis, Bacillus subtilis, Propionibacterium acnes, and Staphylococcus aureus. Extraction temperature significantly influences the chemical composition of tannin, which leads to different antioxidant properties. The maximum antibacterial properties of tannin were obtained at 90°C with the inhibition zone in the range of 0.9–1.0 mm against four bacteria, tannin yield of 26.59%, Gallic Acid Equivalents or total phenolic content (GAE) of 40.30 mg/g, and Radical Scavenging Activity or antioxidant activity (RSA) of 89.88%. Moreover, the concentration of tannin was significantly linear with its antibacterial properties. Tannin was successfully applied to the textile by using alum as a mordanting agent to create an antibacterial textile. The textile's bacterial structure damage was analyzed under Field Emission Scanning Electron Microscopy (FESEM). After 50 washings, tannin-textiles with alum-modified properties remained stable compared to those without alum, with S. aureus and S. epidermidis being the most vulnerable bacteria, as confirmed by FESEM images. Hence, tannin is a feasible alternative to harmful and nondegradable synthetic dyes and antibacterial agents. [ABSTRACT FROM AUTHOR]

This study explored the thermo-chemical properties of industrial hemp hurd with different provenances, maturity stages, and retting protocols. The findings were then compared to hemp hurd used in the fabrication of citric acid-bonded ultra-low-density hemp hurd particleboard. Pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) were employed to document the variability of the hurd and comprehend the potential impact on biobased composite applications. The choice of cultivar, maturity stage, and processing modality significantly influenced the chemical composition, presence of functional groups, and thermal stability of the hurd. Py-GC/MS revealed substantial variations in the lignin-to-carbohydrate (L/C) ratio, along with the absence of fatty acids in certain cultivars. While FTIR signals confirmed consistent functional groups, differences in peak intensities were indicative of carbohydrate variations associated with maturity and retting duration, impacting the availability of hydroxyl groups for, i.e. interparticle bonding in citric acid-based bio-composites. Furthermore, it was observed that shorter retting durations initially enhanced the thermal resistance, but prolonged retting led to accelerated degradation, significantly reducing the hurd's residual mass. The findings indicated notable differences among the samples, emphasizing the importance of investigating variables such as provenance/cultivar, maturity, and processing modality. This assessment is essential to ensure effective agronomic practices that align the raw material characteristics with the specific requirements of intended applications, such as the fabrication of biobased hemp hurd composites. [ABSTRACT FROM AUTHOR]

Melanins are a complex natural pigment that darken the skin, a phenomenon regarded as an esthetic problem in tropical countries such as Indonesia. Melanin can be degraded by various oxidative enzymes such as laccase (Lac) and manganese peroxidase (MnP) which are produced by white rot fungi (WRF). In the current study, we successfully obtained a partial purified Lac-MnP from a tropical WRF called Trametes hirsuta OK271075. Co-catalysis of Lac and MnP in the melanin degradation existed as indicated by the enhancement of degradation upon the addition of mediators for the respective enzymes. The highest degradation was up to 42% in the presence of TEMPO (0.2 mM) and MnSO4-H2O2 (0.75 mM, 0.2 mM) as mediators. The increment was up to 20% compared to treatment without mediators. A higher degradation rate achieved when specific mediators of the enzymes were utilized indicated a synergistic effect of both enzymes that could be used simultaneously for melanin degradation. FTIR and FESEM analysis revealed significant changes in melanin structure between enzyme-treated and untreated melanin. Melanin granules were cracked and exfoliated due to an enzyme attack. Based on Pyrolysis-GCMS analysis, several compounds such as phenols, epoxides, ketones, and carboxylic acids were found in higher amount in the enzyme-treated than untreated melanin. This finding revealed the potency of a new isolated T. hirsuta for new enzyme applications in biotechnology fields, especially to degrade melanin for application in natural whitening cosmetics. [ABSTRACT FROM AUTHOR]

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