Volume 10 Issue 4

With the aim of identifying and exploiting the mycological resources available in the Mexican Sierra Madre Oriental, the lignocellulolytic and pectinolytic potential of autochthonous fungi were evaluated in the present work. A solid media selection system was established in which 74 isolated strains were tested and compared to six international reference strains. The macrofungi Xylaria sp CS121, Inonotus sp CU7, Basidiomycete CH32, Basidiomycete CH23, Xylaria poitei, and Trametes maxima CU1 showed the highest cellulolytic and pectinolytic potential. The greatest lignolytic capability was exhibited by T. maxima CU1 and Pycnoporus sanguineus CS43. Under stirred submerged culture, T. maxima CU1 (cellulases, cellobiose dehydrogenase, manganese peroxidase (MnP), and laccase, with 200, 359, 51, and 267 U/L, respectively) and Xylaria sp CS121 (198 U/L of xylanases) were the highest enzymatic producers. Under stationary conditions, the best producers were Inonotus sp CU7 for cellulases, P. sanguineus CS43 for cellobiose dehydrogenase and laccase, and T. maxima CU1 for xylanases and MnP (242, 467, 35, 165, and 31 U/L, respectively). These results demonstrate the efficiency of enzymatic profiling as a tool for enzyme discovery with Mexican native fungi.

The potential usage of Pinus wood residues in cement-wood composites and the behavior of CaCl2∙2H2O, used as an additive were assessed in this work. In order to improve the interaction between the cement-wood composites, CaCl2∙2H2O and 12 different pre-treatment types were tested. Pre-treatments involved extractions in cold and hot water, NaOH solutions, and several Ca(OH)2 concentrations for different times. An evaluation of the mechanical features (compressive strength and tensile resistances) of composites was also performed using 50 mm cylindrical samples. The interaction of the composites was analyzed using Bragg sensors in optical fibers. Pinus residues were tested having particle size of 4.8 mm and a CaCl2∙2H2O content between 0% and 8%. The highest compressive strength was observed for the production of composites with 4.5% CaCl2∙2H2O and the hot and cold water pre-treatment. Conversely, for tensile strength, the highest performance occurred when NaOH was used as a pre-treatment. The technology for determining the temperature of composites using Bragg sensors in optical fibers was judged to be efficient.

Regenerated cellulose film with better mechanical properties was successfully produced by introducing aldehyde crosslinker during the regeneration process. The cellulose source material was derived from kenaf core powder and dissolved in LiOH/urea solvent at −13 °C to form a cellulose solution. The cellulose solution was cast and coagulated in a crosslinker bath at different percentages of glutaraldehyde (GA) and glyoxal (GX) to form a regenerated cellulose film. According to Fourier transform infrared spectroscopy (FTIR) spectra, the hydroxyl group of the cellulose was reduced, reducing the percentage of swelling as the percentage of crosslinker was increased. X-ray diffraction (XRD) patterns showed that the crystallinity index of the crosslinked film was decreased. The pore size of the films decreased as the percentage of crosslinker was increased, resulting in decreased film transparency. The pore volume and percentage of swelling in water of the films also increased with decreases in the pore size as the percentage of crosslinker was increased. The tensile strengths of the GA- and GX-crosslinked films increased by 20 and 15% with the addition of 20% of each crosslinker, respectively.

Using response surface method to determine the optimal technological conditions of biomass-based precursor preparation, magnetic Fe3O4 particles were loaded on the surface and internal channel of biomass-based precursor to prepare a magnetic biomass-based solid acid catalyst using the sol-gel method. To investigate the performance of the magnetic catalyst, it was used to hydrolyze cellulose into reducing sugar, whose structure was characterized by infrared spectrum analysis. The optimum process conditions of biomass-based precursor preparation was obtained by quadratic regression model as a carbonization temperature of 549 °C, carbonization time of 13 h, sulfonating temperature of 121 °C, and sulfonating time of 6 h. Using the biomass-based solid acid catalyst to hydrolyze cellulose, a reducing sugar yield of 57.36% was obtained. Compared with the traditional solid acid catalysts, the total reducing sugar yield was increased by 65%. The infrared spectrum analysis showed that magnetic Fe3O4 particles were combined successfully with biomass-based precursor. This magnetic biomass-based solid acid catalyst has a carbon structure layer of vermicular disorder and possesses high stability.

The performance of a date palm tree bark-based biofilter inoculated with mixed microbial consortia was investigated for the removal of a benzene- ethylbenzene-xylene mixture at a total inlet loading rate range of 38.0 to 612.0 g/m3·h. The influences of the inlet pollutant concentration and air flow rate were studied. The maximum elimination capacities attained for benzene, ethylbenzene, and toluene were 79.51, 77.47, and 57.08 g/m3·h, respectively. The removal efficiencies were evaluated and found to vary inversely with the inlet pollutant concentration. The VOC conversions were demonstrated by the difference in inlet and exit concentrations. The axial removal performance of the biofilter was studied, and the contribution of the lowest part was comparatively more than those of the upper sections because of the different biomass growth patterns. Temperature monitoring in the biofilter confirmed the exothermic nature of the biodegradation.

The carbonization of lignocelullosic waste to obtain wood vinegar (WV) was investigated in this work. WV was used as a botanical insecticide against armyworm (Spodoptera litura), which is known as a major pest of soybean crops in Indonesia. This study includes the following: (i) the assessment of potential use of lignocellulosic waste from mahogany wooden-sandal home industry; (ii) the determination of the yield of various components of carbonization process, from each unit of the waste; and (iii) the application of the produced WV as larvicide on S. litura larvae in the laboratory. The experiments were arranged in a completely randomized design, and the observed variables included mortality and anti-feedant activity of S. litura larvae. The data were analyzed using analysis of variance with Duncan’s multiple differences test. The results showed that the amount of wood waste generated at wooden-sandal craftsman level was 16.12%. Carbonization of 1,000 g of the wood waste yielded WV, tar, bio-oil, and char in quantities of 442.68 g, 36.5 g, 4.04 g, and 251 g, respectively. The treatment using WV concentration of 1.5% to 3.0% showed low larvacidal action, which gave LC50 value of 12.82%, but it had adequate anti-feedant activity.

Biochars (BC) generated from biomass residues have been recognized as effective sorbents for organic compounds. In this study, biochars as adsorbents for the removal of norfloxacin (NOR) from aqueous solutions were evaluated. Biochars were prepared from cassava dregs at 350 °C, 450 °C, 550 °C, 650 °C, and 750 °C, respectively (labeled as BC350, BC450, BC550, BC650, and BC750). The results showed that the kinetic data were best fitted to the pseudo second-order model, indicating that the sorption was governed by the availability of sorption sites on the biochar surfaces rather than the NOR concentration in the solution. Sorption isotherms of NOR were well described by the Freundlich model, and the Freundlich coefficients (lgkF) increased with the pyrolysis temperature of biochars. Thermodynamic analysis indicated the feasibility and spontaneity of the NOR adsorption process. The NOR adsorption on BC450, BC550, BC650, and BC750 was an endothermic process, while an exothermic process occurred for BC350. FTIR studies further suggested that the adsorption mechanism was possibly attributable to H-bond and π-π interactions between NOR and biochars. Overall, this work constitutes a basis for further research considering the bioavailability and toxicity of antibiotics in the presence of biochar.

To achieve high value-added utilization of lignin extracted from the biorefinery process in the wood composite industry, binderless particle boards were manufactured by bamboo materials combined with alkaline lignin (AL) in various proportions under various hot-pressing conditions. To elucidate the reactivity and chemical transformations of lignin macromolecules during the hot-pressing process, lignin samples were isolated from the corresponding boards and characterized by high-performance anion-exchange chromatography (HPAEC), gel permeation chromatography (GPC), quantitative 31P-NMR, and 2D-HSQC NMR. The best bonding strength (1.36 MPa) of the binderless particle boards was obtained under the conditions of 180 °C, pressure 5 MPa, and lignin/bamboo mass ratio 0.4. The molecular weight of the lignin samples decreased from 3260 to 1420 g/mol during hot-pressing. The NMR results showed that the contents of β–O-4′ and β-β’ linkages were reduced and β-5′ linkages were increased as the hot-pressing temperature rose. Simultaneously, the percentage of G-type and H-type lignins as well as the content of phenolic OH increased.

Tensile properties of bamboo fiber (BF)/polypropylene (PP) composites were investigated for different impregnation modification processes. The surface morphology of BF and the fracture morphology of the BF/PP composites were examined by scanning electron microscopy (SEM). Images showed that CaCO3 nanoparticles (nano-CaCO3) adhered to the fiber surfaces. Tension tests of individual bamboo fibers (IBFs) and the BF/PP composites were conducted. The results indicated that the tensile strength (TS), modulus of elasticity (MOE), and elongation at break (EAB) of IBFs increased by 16.0%, 22.2%, and 5.2%, respectively, while those of the BF/PP composites increased by 3.0%, 7.0%, and 15.8%, respectively, compared to the control samples. Various process parameters during the impregnation with nano-CaCO3 had marked effects on the tensile properties of the composites. The optimal conditions for BF-reinforced PP composites by impregnation modification were determined to be a nano-CaCO3 concentration of 1.0×10-2 g/mL, an ethylenediamine tetraacetic acid disodium salt (EDTA-2Na) additive concentration of 8.5×10-4 g/mL, and an impregnation time of 25 min.

An artificial neural network (ANN) approach was employed for the prediction and control of surface roughness (Ra and Rz) in a computer numerical control (CNC) machine. Experiments were performed on a CNC machine to obtain data used for the training and testing of an ANN. Experimental studies were conducted, and a model based on the experimental results was set up. Five machining parameters (cutter type, tool clearance strategy, spindle speed, feed rate, and depth of cut) were used. One hidden layer was used for all models, while there were five neurons in the hidden layer of the Ra and Rz models. The RMSE values were calculated as 1.05 and 3.70. The mean absolute percentage error (MAPE) values were calculated as 20.18 and 15.14, which can be considered as a good prediction. The results of the ANN approach were compared with the measured values. It was shown that the ANN prediction model obtained is a useful and effective tool for modeling the Ra and Rz of wood. The results of the present research can be applied in the wood machining industry to reduce energy, time, and cost.