WOOD RESEARCH Volume 67, Number 4, 2022
Xiaoyan Zhang and Guangjie Zhao

Yeast cultivation for single-cell protein production using the carbohydrate hydrolysate of steam-exploded eucalyptus wood

This study was aimed at producing single-cell (SCP) protein from the carbohydrate hydrolysate of steam-exploded eucalyptus (Eucalyptus urophylla) wood. Two yeast strains including Saccharomyces cerevisiae and Candida utilis 2.587 were used for batch fermentation. Results showed that the total reducing sugars (TRS), glucose and xylose in hydrolysate had concentrations of 17.52, 10.71, and 4.30 g•L-1, respectively. During fermentation, yeast strains of S. cerevisiae and C. utilis 2.587 used monosaccharides sequentially, and secondary growth occurred. The yeast biomass contained 43.59% crude protein and was rich in all essential amino acids such as lysine, leucine, and valine. Total amino acid reached 401.45 g•kg-1, and corresponded with the standard recommended by the Food and Agriculture Organization of the United Nations for amino acids, except sulfur-containing amino acids.

WOOD RESEARCH Volume 61, Number 3, 2016
Weiyi Li, Lijuan Zhao, Qiuhui Zhang, and Guangjie Zhao

Flame retardance and antibacterial performance of wooden wallpaper treated with composite modifying agent

To improve the flame retardance and antibacterial properties of wooden wallpaper, a composite modifying agent, containing primarily a phosphorus-nitrogen flame retardant (APP/PER/GP), synergistic and smoke suppression agent (OMMT) and silver loaded with nano TiO2 (Ag-TiO2), was prepared and applied to the wooden wallpaper using an ultrasonic immersion method. The combustion performance (including smoke suppression performance), antibacterial activity and the surface micrographs of the flame retardant/antibacterial wooden wallpaper (FRAW) were investigated and characterized using a cone calorimeter test (CCT), antibacterial rate (AT) and inhibition zone, atomic force microscope (AFM), field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS). Furthermore, CIE1976 (L* a* b*) color system was used to estimate the surface color change of the FRAW. It was found that the composite modifier distributed on the surface of FRAW with a micrometer, improved the flame retardance of FRAW, but also improved its antibacterial property. In addition, the smoke release behavior of the FRAW indicated that OMMT had good smoke suppression properties. Furthermore, the result of color difference test showed that the flame retardant and antibacterial treatment had little effect on the decorative appeal of the wooden wallpaper.

WOOD RESEARCH Volume 62, Number 6, 2017
Enhua Xi and Guangjie Zhao

Visual simulation on accumulation of the differentiating secondary wall layers

This study describes the accumulation of secondary wall layers of the fast-growing Populus×euramericana cv. ‘74 /76’ during the active phase by the methods of polarized light microscopy analysis and computer simulation technology. The results showed that the secondary wall layers of Populus×euramericana cv.‘74/76’ appeared light and shade stratification during the differentiating phase, and the wall layers corresponded to S1, S2 and S3 layer from outside to inside respectively. The S1 and S2 layer of wood fibers were differentiated in May, and the S3 layer was appeared until the July. In addition, the thickness of the three layers all showed a gradual increasing trend. The accumulation process of the secondary wall layers was visually displayed by the computational simulation technology during the active period.