Volume 16 Issue 4

Using commercial API-ZYM screening kits, highly active α-glucosidase, β-glucosidase, and β-N-acetylglucosaminidase were found in Grifola frondosa, having potential for carbohydrate utilization. Of these, β-N-acetylglucosaminidase, which converts chitin to N-acetylglucosamine, was purified and characterized. The recovery was 24.5%, and the purified enzyme had a specific activity 0.67 U/mg protein. Chitinase activity was confirmed by zymogram analysis. The enzyme was also shown to be β-N-acetylglucosaminidase, as N-acetylglucosamine was the main hydrolysis product from colloidal chitin. Thus, the molecule was named NAG38, to indicate β-N-acetylglucosaminidase activity and a molecular weight of 38 kDa, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Enzymatic activity was optimal at pH 7.0 and 50 °C, with Km and Vmax values of 0.112 mM and 0.570 μmol/min/mg protein against p-nitrophenyl N-acetyl-β-D-glucosaminide. The bioactivity was inhibited by Hg2+, Ag+, Mg2+, Zn2+, Ca2+, and Mn2+, with residual enzyme bioactivity only 11.1% after incubation in Hg2+, but was not substantially inhibited by Ba2+, K+, and Na+.

The overall usefulness of the bursting energy absorption (BEA) was studied for a better analysis of paper strength properties. Additionally, the changes of the BEA during more complex deformations of paper products, e.g., preliminary or simultaneous tensile and burst, were determined. For the purpose of the research, an experimental setup was designed. The results showed that the correlation between BEA and bursting strength was linear, but the proportionality strongly depended on paper grade. Thus, a more accurate method to characterize the bursting resistance (BR) of paper was proposed. The BR parameter is described by the three following parameters: average bursting strength, average bursting energy absorption, and the slope of the fitted linear regression curve (relationship between the bursting energy absorption and the bursting strength). This method revealed new mechanical behaviors of papers related to their preloading.

A cellulose polymer functionalized with an amine chelating agent was designed and synthesized in a three-step process that involved oxidizing cellulose powder into dialdehyde cellulose, reacting cellulose dialdehyde with phenyl biguanide to create an imine linkage between the two reactants, and reducing the imine linkage to an amine. The cellulose amine polymer was cross-linked with glycerol digycidyl ether and evaluated as an adsorbent of toxic metal ions from wastewater. The adsorption efficiency of the cross-linked cellulose amine polymer toward Pb(II) and Cu(II) was evaluated as a function of the adsorbent dose, pH, time, temperature, and initial ion concentration. The cross-linked cellulose amine polymer showed an excellent efficiency toward over 15 metal ions present in a real sample of sewage. Thermodynamic analysis showed a spontaneous adsorption of metal ions on the polymer at room temperature. Monte Carlo and Molecular Dynamic simulations showed that the Cu(II) and Pb(II) ions adsorbed onto the cellulose amine polymer surface in a considerable amount, which agreed with the experimental and thermodynamic data. The negative free energy value confirmed the spontaneity of the adsorption process. As such, cross-linked cellulose amine polymers could be a promising alternative to current commercial adsorbents.

The import activity of wooden prefabricated buildings in the Northeastern US region was over CAD 41.8 million during 2019, according to the US Census Bureau. This amount was growing at a 12.5% annual rate on average since 2017. There is evidence of a continued shortfall in supply for the construction market to be overcome in the region. The objective of this study was to estimate the export potential of wooden prefabricated buildings from the Province of Quebec to the Northeastern US region for the next decade in relation to the export activity and production capacity of the industry. The value of annual production of wooden prefabricated buildings in Quebec was up to CAD 578 million in 2019, according to iCRIQ. Export activities from Quebec are mainly directed to the Northeastern US, and were of CAD 18.8 million in 2019, or 81% of Quebec’s wooden prefabricated building exports. Results suggest that potential for wooden prefabricated building exports from the Province of Quebec to the US Northeastern region is important in terms of market share. The study also suggests that by drastically increasing the production capacity of the industry there is no chance that supply will overcome demand.

Jerusalem artichoke residue (JR) was co-ensiled with grain stillage (GS) at various weight mixing ratios (JR only, 4 to 1, 2 to 1, 1.2 to 1, 1 to 1.5, 1 to 2.7, 1 to 7, and GS only) for 10, 30, and 60 d for agricultural biomass storage. Results showed that the middle level of GS to JR ratios, e.g., 1.2 to 1 and 1 to 1.5, achieved the best co-ensiling performance among all studied ratios. The water-soluble carbohydrate (WSC) contents were significantly higher than those of the other treatments (p < 0.05), and the lignocellulose contents were significantly lower than those of other treatments (p < 0.05). The silages ensiled at the above-mentioned ratios had a higher feed value and biodegradation potential than other ratios. Lactobacillus was the dominant bacterial species during the ensiling process, and its relative abundance was significantly correlated with the content of different components, e.g., WSC, crude protein, and starch, as well as fermentation characteristics. Fungal species, e.g., Kluyveromyces and Monascus were also observed, and the relative abundance of which was positively correlated with different nutritional components. In conclusion, GS and JR can be successfully stored via co-ensiling.

Laccase activity from Pleurotus ostreatus and Flammulina velutipes strains was investigated with various agro- and forestry residues by solid-state fermentation. Different species or strains belonging to the same species had the unique capacity of secreting laccase on solid-state fermentation with various agro- and forestry residues. Overall, the capacity of secreting laccase for P. ostreatus strains was superior to F. velutipes strains due to the value of maximum activity on various agro- and forestry residues, except on the stalk of straw. Compared with Populus beijingensis, corncob, and stalk of straw, the presence of cottonseed hull was helpful to improve laccase activity for P. ostreatus strains because the maximum laccase activity from cottonseed hull was higher than that from the other three agro- and forestry residues. The presence of stalk of straw was more helpful to improve laccase activity for F. velutipes strains because of the maximum laccase activity from stalk of straw was higher that from Populus beijingensis, corncob, and cottonseed hull. These results indicated the importance of selecting suitable agro- and forestry residues for fungi producing laccase. These findings contributed to the selection of suitable strains to obtain an integrated application of low-cost laccase in the factory.

The surface properties of thermally modified ash wood with a powder coating were investigated, and the results were compared to the unmodified wood. The wood specimens were sanded with 80 grit sandpaper and then pre-heated at 80 °C for 5 min in an infrared oven. The surface of the unmodified and the modified wood specimens were coated with an epoxy/polyester (1 to 1 ratio) hybrid coating using an electrostatic corona spray gun at the pilot plant established in the laboratory. The coatings on the wood specimens were cured at different curing conditions in an infrared oven, i.e., 120 °C/15 min, 140 °C/10 min, and 160 °C/10 min. The results showed that the thermal modification (TM) of the wood caused a slight decrease in the mechanical performance of the surface system (wood substrate and coating film). For example, the scratch and abrasion resistance of the unmodified specimens at the curing temperature of 120 °C were 3.33 N and 135 revolutions but were 3.12 N and 120 revolutions after the TM. However, the average surface roughness (1.26 mu) and contact angle (60.8°) of the distilled water on the cured coatings on the modified wood were lower than those on the unmodified wood (1.86 mu and 80.8°, respectively).

Response surface methodology was utilized to optimize the microwave-assisted extraction of flavonoids from Eucommia ulmoides Oliver seed meal. In addition, the optimal processing conditions for the extraction of E. ulmoides seed meal flavonoids were as follows: a processing time of 30 min, a liquid to solid ratio of 54 to 1 (mL/g), an ethanol concentration of 77%, and a temperature of 69 °C. The total flavonoids extraction percentage was 0.6611%. Moreover, the total flavonoids extracted from E. ulmoides seed meal were good for scavenging diphenyl picryl hydrazinyl. The E. ulmoides seed meal total flavonoids exhibited an obvious dose-dependent inhibitory effect on α-glucosidase in the concentration range of 0.05 to 1.0 mg·mL−1. The IC50 value of the E. ulmoides seed meal flavonoids was slightly lower than the IC50 value of acarbose. According to the results of the xanthine oxidase inhibitory activity test, the IC50 value of the E. ulmoides seed meal flavonoids was higher than the IC50 value of allopurinol.

The present study was performed during two successive seasons 2019 and 2020 to investigate the effect of the soil application of fulvic acid (FA), seaweed extract (SE), and their different combinations on vegetative growth, yield, and fruit quality of six-years-old guava (Psidium guajava L.) cv. ‘Maamoura’. The trees were planted 4 × 4 m2 apart in clay soil under a flood irrigation system. They were treated three times starting from mid-March with one-month intervals with the following treatments: Control (water only), 3 and 4 g/L FA, 3 and 4 g/L SE, and their different combinations; 3 g/L FA + 3 g/L SE, 3 g/L FA + 4 g/L SE, 4 g/L FA + 3 g/L SE, and 4 g/L FA + 4 g/L SE. The results clearly showed that the application of FA or SE solely or in combinations increased shoot length and diameter, as well as leaf chlorophyll compared with the control. The treatments also increased fruit set percentage, fruit yield, and fruit physical and chemical characteristics such as fruit weight, size, TSS%, total reduced and non-reduced sugars, as well as leaf mineral content, while they decreased the fruit acidity compared with the control in the two seasons.

To investigate the changes of larch wood properties under the influence of long-standing exposure to the environment, the QUV accelerated weathering tester (fluorescent UV and condensation testers) was used to accelerate the weathering of wood within a given preset time, and the changes were studied by analogue simulation. The wood color changed noticeably under different weathering time, and it gradually darkened from light yellow to deep reddish brown. Scanning electron microscopic (SEM) analysis revealed that as the weathering time increased, the cell wall was broken, the pits were cracked, and the tracheids were damaged. The results of the energy spectrum analysis (O/C (oxygen/carbon)) showed an increasing trend in the ratio, indicating that the wood underwent an oxidation reaction induced by light. From the values of the two testing indexes and their change patterns with weathering time, the same trend was observed, with the values of modulus of elasticity (MOE) in static bending being greater than that in dynamic bending Ed (the dynamic modulus of elasticity). However, the variability of MOE was greater than that of Ed. A comparative analysis of the two detection indicators was performed. The relationship between the proposed combined correction Ed and weathering time was: y = 0.0000001017 t2 – 0.0006 t + 9.77.