Volume 9 Issue 1

The epidermis layer waste (ELW) and the inner layer waste (ILW) were removed from Phyllostachys pubescens bamboo, and the anatomical characteristics and chemical components of these wastes were comparatively investigated. Both the ELW and ILW were subjected to a microwave-assisted liquefaction process to evaluate the relationship between bamboo properties and liquefaction behavior. The results indicated that higher vessel and parenchyma percentages and lower cellulose and lignin contents in ILW contributed to lower residue content, while higher fiber percentage and cellulose or lignin contents in ELW resulted in higher residue content. Recondensation took place during the liquefaction of ELW, which was indicated by small granules appearing on the liquefied residue surface according to SEM images. The intense bands corresponding to hemicellulose and lignin in the FT-IR spectrum of the liquefied ELW residue gave further evidence that the liquefaction of ELW is a complex solvolysis process involving simultaneous reactions of chemical degradation and recondensation.

Wheat bran (WB) was subjected to processing with Aureobasidium pullulans (A. pullulans) under selected conditions to partially break down the xylan into soluble products (mainly feruloyl oligosaccharides, FOs). The objective of this study was to investigate the technology for one-step fermentation of WB by A. pullulans without melanin secretion to produce FOs as well as to determine their structural features and antioxidant activity. Initial pH, inoculation quantity, and fermentation temperature were found to be efficient for releasing FOs according to the Plackett-Burman design (PBD). Based on the D-Optimal design, a yield of 904 nmol of FOs / L of fermentation broth was obtained under optimal conditions of initial pH 6.0, inoculation quantity 4.50%, and fermentation temperature 29 oC. Purification of FOs was performed with alcohol precipitation and Amberlite XAD-2. GC, IR, and ESI-MS demonstrated that FOs consist of feruloyl arabinosyl xylopentose (FAX5, Mw986), feruloyl arabinosyl xylotetraose (FAX4, Mw854), feruloyl arabinosyl xylotriose (FAX3, Mw722), and feruloyl arabinosyl xylobiose (FAX2, Mw590). Increasing the FO dose led to increased activity of SOD and GSH-Px in serum of S180 tumor-bearing mice, while the level of MDA was reduced, thus improving its in vivo antioxidant activity.

A proposed method for citronella oil extraction was developed with the application of ohmic heated hydro-distillation. The objective was to compare the performance of three different extraction methods, viz. ohmic heated hydro-distillation, hydro-distillation, and steam distillation. The maximum amount of extracted oil yield by ohmic heated hydro-distillation was 7.64 mL/kWh as compared to hydro-distillation and steam distillation methods that resulted oil yields of 3.87 mL/kWh and 1.69 mL/kWh, respectively. The kinetics of extraction followed a second-order model. Gas chromatography-mass spectrometry analysis found that the major constituents of citronella oil (GC-MS) for the different extraction methods were citronellal, citronellol, and geraniol. Scanning electron microscopy (SEM) of citronella grass provided evidence that the lignocellulosic sources of the extracted citronella oil were schizogenous cavities and cellular lignin. The citronella that had undergone ohmic-heated hydro-distillation and steam distillation showed some microfractures and less cell wall degradation than hydro-distillation. The cell walls were less rigid using ohmic-heated hydro-distillation compared to steam distillation. However, the cell walls of the hydro-distillation sample were less dense and exhibited pronounced swelling, but did not show any microfractures.

Active anti-microbial effects of larch (Larix decidua Mill.) and pine (Pinus sylvestris L.) wood materials on Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecium, and Bacillus subtilis were tested. The agar-diffusion test, a method used in routine diagnostics, was implemented to detect anti-microbial effects of wooden discs and filter paper discs containing methanol extracts of different wood parts. The results showed that the bark of larch had an inhibitory effect on Staphylococcus aureus, and the heart wood of pine showed a significant anti-microbial effect on the gram-positive bacteria tested (Staphylococcus aureus, Enterococcus faecium, and Bacillus subtilis). These results were confirmed by using methanol-extracts. An anti-microbial activity against Pseudomonas aeruginosa was not found. Anti-bacterial effects of other parts of larch wood and of pine sapwood were also not found. The results of this study showed for the first time that certain parts of wood contain compounds that directly reduce microbial growth. These data are a further demonstration of the positive effects of specific wood species and could promote the usage of wood in hygienically sensitive areas.

This study’s main objective was the dissolution of cellulose from biomass using ionic liquids to obtain saccharides by prehydrolysis. Raw materials were exposed to the ionic liquids (ILs) 1-ethyl-3-methylimidazolium acetate, 1-butyl-3-methylimidazolium chloride, 1-ethyl-2,3-dimethyl-imidazolium chloride, and 3-(2-methoxy-2-oxoethyl)-1-(3-methoxy-3-oxo-propyl)-imidazolium bromide at 105 °C for 6 h. The sugar content of the liquid phase was characterized by high-performance liquid chromatography (HPLC). The vegetal materials after treatments were characterized by Fourier transform infrared spectroscopy (FTIR). Glucose was the main reducing sugar product in each case. Different ILs were found to be most effective, depending on what sample was being dissolved – microcrystalline cellulose or rapeseed stalk.

Planted forests can meet the world’s demand for wood. In Brazil, eucalypt species are cultivated on a large scale, but their dimensional instability and color limit their use, which makes heat treatment necessary. The aim of this study was to evaluate physical and colorimetric properties of Eucalyptus grandis after heat treatment at 140, 170, 200, and 230 °C for 3 h. Mass loss, shrinkage, equilibrium moisture content, volumetric swelling, fiber saturation point (FSP), and colorimetric parameters were determined; photos were also taken with a scanning electron microscope for all treatments. Heat treatment reduced the wood mass by 0.33 to 10.64% and caused shrinkage by 0.23 to 5.16%. Treatment at 230 °C reduced oven dry density. Equilibrium moisture content was 9.40, 9.34, 8.55, 6.55, and 5.05% for control and test samples treated at 140, 170, 200, and 230 °C, respectively. Heat treatment reduced thickness swelling and FSP by 59.65% and 56.31%, respectively. Heat treatment also reduced the L* (lightness), a* (green–red coordinate), and b* (blue–yellow coordinate) values of the wood samples. Heat treatment improved physical properties and darkened the wood; however, the damage observed in scanning electron microscope images could reduce the mechanical properties of wood.

Recently, much attention has been paid to the development of technologies that facilitate the conversion of biomass into platform chemicals such as 5-hydroxymethylfurfural (5-HMF). In this paper, a tin-containing silica molecular sieve (Sn-MCM-41) was found to act as a bifunctional heterogeneous catalyst for the efficient conversion of glucose into 5-HMF in ionic liquid. In the presence of [EMIM]Br, the yield of 5-HMF converted from glucose reached 70% at 110 °C after 4 h. During the reaction, the active center of the catalyst first catalyzed the isomerization of glucose into fructose and then the dehydration of fructose into 5-HMF. After the reaction, the heterogeneous catalyst Sn-MCM-41 could be easily recovered and reused without a significant loss in activity. The catalyst Sn-MCM-41 was also able to catalyze the conversion of fructose into 5-HMF at an 80% yield. Moreover, the low toxicity of the Sn-based catalyst makes the method a greener approach for the conversion of saccharides into 5-HMF.

Bacterial community structure and biochemical changes during the composting of lignocellulosic oil palm empty bunch (EFB) and palm oil mill effluent (POME) anaerobic sludge were studied by examining the succession of the bacterial community and its association with changes in lignocellulosic components by denaturing gradient gel electrophoresis (DGGE) and the 16S rRNA gene clone library. During composting, a major reduction in cellulose after 10 days from 50% to 19% and the carbon content from 44% to 27% towards the end of the 40-day composting period were observed. The C/N ratio also decreased. A drastic change in the bacterial community structure and diversity throughout the composting process was clearly observed using PCR-DGGE banding patterns. The bacterial community drastically shifted between the thermophilic and maturing stages. 16s rRNA clones belonging to the genera Bacillus, Exiguobacterium, Desemzia, and Planococcus were the dominant groups throughout composting. The species closely related to Solibacillus silvestris were found to be major contributors to changes in the lignocellulosic component. Clones identified as Thermobacillus xylanilyticus, Brachybacterium faecium, Cellulosimicrobium cellulans, Cellulomonas sp., and Thermobifida fusca, which are known to be lignocellulosic-degrading bacteria, were also detected and are believed to support the lignocellulose degradation.

Adsorption characteristics of palm oil boiler mill fly ash (POFA) for the removal of Cu(II) from aqueous solution were investigated using batch adsorption studies. The effects of relevant parameters such as contact time, solution pH, adsorbent dosage, and initial concentration of copper were examined. Fundamental batch investigations indicated that 90% of the Cu(II) was removed in the first 30 min, achieving equilibration after only 270 min of agitation. The Cu(II) uptake mechanism is particularly pH- and concentration-dependant, favoring a pH value of 6.0. A decrease in adsorption capacity (qe) with an increase in Cu(II) removal efficiency (RE %) was obtained as the adsorbent dosage increased. The adsorption behavior of Cu(II) fit well to the Langmuir isotherm, with a monolayer adsorption capacity of 17 mg/g. The applicability of the Langmuir isotherm suggested the formation of monolayer coverage of Cu(II) ions onto equivalent sites of the adsorbent. Kinetics experimental data followed the trend of pseudo second-order kinetics, which is consistent with chemisorption with intraparticle diffusion as one of the rate-determining steps. Therefore, this study indicates that POFA could be used successfully as a natural low-cost adsorbent for Cu(II) removal from aqueous solutions.

Forest vegetation plays a crucial role in improving the ecological environment and maintaining the regional ecological balance. However, most studies pay little attention to the factors that can impact forest biomass carbon storage (FBCS). This research estimated the FBCS by combining relevant forest inventory data and models of continuous functions for biomass expansion factor. A modeling equation was then established and applied to examine the impact of socioeconomic factors on FBCS in Jiangsu, a coastal province in Eastern China, as a case study. The results showed that Jiangsu’s FBCS increased by 20.28 Tg from 2005 to 2010, showing a prominent carbon sink effect but with spatial imbalance among the changes in carbon storage. Jiangsu’s FBCS is significantly affected by land use factors (e.g., forest area and cultivated area), population factors (e.g., population density and urbanization), and economic development factors (e.g., GDP). Relatively speaking, the forest area and GDP had positive effects on FBCS, while cultivated area, population density, and urbanization had significant negative effects.