Round bamboo has drawn more and more attention in architecture, decoration and recreational products. Splitting brings some safety problems, which shorten the service life of round bamboo. In this paper, three schemes were adopted as follows to solve the problem: round bamboo was impregnated in polyethylene glycol (PEG)-1000 solution alone, heat treatment in paraffin alone or treated with the combination of PEG impregnation and paraffin heat treatment (PEG–PH). The treated bamboo was exposed outdoors for 26 weeks to evaluate the development of cracks. Results showed as follows: the initial split of PEG–PH-treated bamboo appeared after 22 weeks, while that of the controls after 2 weeks, the total length of cracks was 2271.31 and 873.5 mm for the control and PEG–PH-treated bamboo, respectively. To reveal the reasons for reduced cracks, scanning electron micrograph (SEM) was employed to observe the microstructure of bamboo; besides, hydrophobicity of bamboo was characterized by the water contact angle. PEG can swell the cell wall and the better hydrophobicity of round bamboo could be achieved after PEG–PH treatment. Therefore, the combination of PEG immersion and paraffin heating is an effective and practicable method in bamboo treatment, especially for round bamboo with high moisture content.

Bamboo timber is very vulnerable to mould fungi, a characteristic that is attributed to the rich sugar, starch, and protein present in bamboo. Solvents including cold water, hot water, benzene/ethanol, ethanol/ether, 1% NaOH, and 1% HCl can dissolve corresponding components from bamboo, which might be helpful to the resistance of bamboo against mould fungi. In order to study the relationship between surface nutrition and mildew of bamboo, mould resistances of bamboo blocks treated with different solvents were tested in the laboratory and field. Results showed that bamboo treated with cold water, hot water, benzene/ethanol or ethanol/ether had almost the same resistances with the controls against mould fungi, and the surfaces became covered with mycelium within 10 days in laboratory tests, and 5 weeks in field tests. 1% NaOH and 1% HCl were helpful to the mould resistance of bamboo, of which, 1% HCl treatments behaved the best, especially in the s.

Development of new drugs is one of the solutions to fight against the existing antimicrobial resistance threat. Cinnamaldehyde-amino acid Schiff base compounds, are newly discovered compounds that exhibit good antibacterial activity against gram-positive and gram-negative bacteria. Quantitative structure–activity relationship (QSAR) methodology was applied to explore the correlation between antibacterial activity and compound structures. The two best QSAR models showed R² = 0.9354, F = 57.96, and s² = 0.0020 against Escherichia coli, and R² = 0.8946, F = 33.94, and s² = 0.0043 against Staphylococcus aureus. The model analysis showed that the antibacterial activity of cinnamaldehyde compounds was significantly affected by the polarity parameter/square distance and the minimum atomic state energy for an H atom. According to the best QSAR model, the screening, synthesis, and antibacterial activity of three cinnamaldehyde-amino acid Schiff compounds were reported. The experiment value of antibacterial activity demonstrated that the new compounds possessed excellent antibacterial activity that was comparable to that of ciprofloxacin.

Current antimold agents that capitalize on broad spectrum biocidal toxicity for their efficacy can create potential hazards in the environment, as in many cases these biocides are not chemically bonded to the wood. They can therefore leach into the ecosystem to jeopardize off-target organisms. In this study, “bio-catalysis” of potassium iodide (KI) was used to impart non-diffusible antimold properties to 4-year-old bamboo, and the mechanisms of how this system works against Aspergillus niger and Trichoderma viride fungi were also studied. In addition to the bamboo block material tested, powdered samples of lignin, cellulose and hemicellulose were studied to better understand binding of iodide to the chemical subcomponents of the bamboo cell walls. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses were used to investigate the sample chemistries and antimold mechanisms, respectively. The results revealed that a specific ratio of laccase enzyme with a laccase-mediator functioned best in binding KI to bamboo. Lignin samples showed the greatest changes in FTIR, especially relative to the methoxyl groups and aromatic skeleton. Additionally, enzyme activity on lignin moieties showed much more differences than on hemicellulose and cellulose after biocatalyzed KI modification. Moreover, the XPS binding energy readings of 621.1 and 632.7 eV (Aromatic region) for lignin were consistent with I–C binding associated with its phenolic structures. While the 620.7 eV (Aliphatic region) suggested I–C bonding that associated with residual lignin in hemicellulose, no peaks were observed for the iodine 3d XPS spectra of treated cellulose. XPS analyses of the O/C and C1/C2 ratios revealed that the formation of I–C bonds was likely due to the substitution of oxygen-contained groups which were formed from laccase-catalyzed oxidation. Thus, enzyme-catalyzed formation of I–C bonds with bamboo chemical constituents is a highly effectual, as well as an ecological method to protect bamboo against mold colonization in the present research.