Earticle

Hydrothermal carbonization of carbohydrates is a low-cost and high-sustainability method for the preparation of multi-functional carbon microspheres materials. While, the hydrothermal preparation of carbon microspheres still has some problems, such as serious adhesion, low specific surface area and poor synthesis repeatability. In view of these shortcomings of hydrothermal carbon microspheres, a method of controllable synthesis of uniform carbon microspheres with cobalt acetate as structure-directing agent was developed by using xylose as model carbon source. By comparing the thermal carbonization effects of various metallic salt (Ni\Al\Co acetate) under different reaction conditions, cobalt salted carbon spheres (220°C, 6h) with low specific surface area and high stability were selected. It is then sulfonated to give it specific functions. And the functionalized carbon microspheres were characterized by a range of methods including SEM, XRD, FTIR and TGA. Based on its high acidity, the catalysis for the preparation of furfural from xylose was attempted. And the effect of reaction time, and reaction temperature on furfural production were investigated and optimized.

The production of platform chemicals from lignocellulosic biomass is scientifically valuable but technologically challenging. With the aim to establish a green reaction system for the production of furfural from lignocellulosic biomass, in the current work, H-SAPO-34 was investigated for catalysis of the conversion of Eucalyptus sawdust to furfural in γ-valerolactone (GVL). H-SAPO-34 was prepared and characterized by XRD, SEM, FTIR, BET, TGA and ammonia adsorbed FTIR. H-SAPO-34 possesses Brønsted and Lewis acid sites and a large specific surface area. The average pore diameter of H-SAPO-34 was 0.86nm, which is beneficial for the spread of xylose and furfural and the inhibition of humin production. In this work, a peak furfural yield of 99.28% from Eucalyptus was achieved at 210 °C in 120 min with 30g/L H-SAPO-34. The Brønsted/Lewis acid bifunctionality and the solvent effect of γ -valerolactone possibly contributed to the high furfural yield from real biomass. The kinetics of the conversion of Eucalyptus sawdust to furfural was also studied, and the activation energy for furfural pro-duction was calculated. Additionally, the catalytic activity and stability of the regenerated catalyst were esti-mated.

Enhancing the high-value utilization of waste plant extract residues in pulp and paper industry is a challenge. Here, the extraction residue of ginseng was firstly obtained through four processes: extraction, concentration, removal of residual drugs and spray drying, as illustrated in Figure 1. Subsequently, this ginseng extract residue blended wood pulp (bleached eucalyptus kraft pulp) as raw material, which was applied in pulp and paper industry to study the paper-making mechanism and properties of business card base paper. Forming morphology, structures and strength of the prepared paper were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD), thermal weight analysis (TGA), scanning electron microscope (SEM), paper physical performance tests. The results showed that the paper retained the basic chemical structure of cellulose. Compared with pure wood pulp paper, the paper not only can ensure its physical strength performance, but also display product characteristics in business and interpersonal communication, and it plays the media function of information exchange. Therefore, the above methods are of great significance in reducing environmental pollution, saving forestry resources, developing new products and creating economic value. It is also expected to realize the characteristic application of pulp and paper and natural product extraction industry.

With the large consumption of fossil fuels and the gradual rise of the "low-carbon" revolution worldwide, the use of biomass renewable resources to prepare fuels and chemicals has become a general trend, and has attracted the increasing attention of scientists in related research fields. Biomass is a renewable carbon resource, which is rich in sources and can be converted into various liquid fuels. Therefore, the development of biomass energy is of great significance to replace traditional fossil fuels. In China, crop straw is one of the most common biomass renewable resources. In the past, it was often discarded as waste or burned as low-grade fuel with low utilization rate. In order to reduce production cost and achieve sustainable development, the common biomass corn straw was used as raw material to produce acetylpropionic acid (LA). Traditionally, inorganic acids have been used as catalysts to prepare LA. Although inorganic acid as catalyst can also achieve considerable yield, there are still some problems: 1) Difficulty in acid recovery, waste water discharged in the preparation process can cause environmental pollution; 2) High acid concentration requires high requirements on the equipment, in order to increase the corrosion resistance of the equipment will increase the production cost. In order to solve these problems, solid acid catalysts attract researchers’ attentions. Among them, mesoporous HY is an effective solid acid to prepare LA, which has attracted extensive attention. Modification is also a feasible method, and in this paper, we introduced a novel process to modify it to prepare high yield LA.

Deep eutectic solvents (DESs) are nontoxic, low vapor pressure, biodegradable, chemically stable and environmentally friendly solvents. Among the various DES solvents we are interested in DES based on choline chloride. Choline chloride acts as a hydrogen bond acceptor (HBA) and combines with other hydrogen bond donors (HBD) such as urea, carboxylic acids, sugars or alcohols to form a low melting eutectic mixture. It affects the physical and chemical properties of DES, such as its melting point. Therefore, in this study, the effects of treatment temperature on the chemical composition change of Quercus mongolica wood by choline chloride based eutectic solvent (1: 2 molar ratio) were investigated. The deep eutectic solvent pretreatment temperature was carried out at 100℃ and 140℃. The yield by all DES treatments decreases with increasing processing time. ChCl/lactic acid showed the lowest yield compared to other DESs. ChCl/urea and ChCl/glycerin showed similar characteristics. The chemical composition of the ChCl/lactic acid eutectic solvent decreased with increasing treatment time, but increased with increasing treatment time at 140℃. ChCl/urea and ChCl/glycerin showed little change of lignin and change of cellulose and hemicellulose at 140℃. The crystallinity of cellulose was slightly higher than that of other eutectic solvents, but it was not affected by the treatment temperature.

Deep eutectic solvent (DES) can be considered a next-generation ionic solvent consisting of a mixture of two or more compounds, one of which is a salt. The formation of new liquid compounds at room temperature is due to the formation of hydrogen bonds between the hydrogen bond donor (HBD) and the hydrogen bond acceptor (HBA), generally the halide anions present in the salt. This DES is a fairly new kind of green solvent that can be applied to various fields, and attracts much attention as an alternative to IL. This study examines the choline chloride-based DES treatment as a new pretreatment for the production of cellulose nanofibers. In the Experiments, deep eutectic solvent systems having lactic acid, urea and glycerin as the second component were formed at 100 °C and then applied to decompose wood-derived cellulose fibers. DES-pretreated fibers were nanofibrillated by mechanical treatment using a blender and their properties were analyzed. Cellulose nanofibrils with a width of 4.7 to 5.4 nm were successfully produced from DES pretreatment under all conditions. As a result, choline chloride-based DES has shown high potential as an environmentally friendly solvent in the production of cellulose nanofibrils.

This study aimed to observe and to compare the microfibril angle (MFA), crystalline characteristics, and chemical compounds in compression wood (CW), lateral wood (LW), and opposite wood (OW) in the stem wood of Korean red pine (Pinus densiflora). The MFAs of CW, LW, and OW were determined by using iodine staining methods and optical microscopy, while the crystalline characteristics and chemical composition were measured by an X-ray diffraction method and FT-IR spectroscopy, respectively. The CW had the greatest MFA, whereas the OW showed the smallest MFA. The relative crystallinity of CW was the lowest, whereas the OW showed a slightly greater value than that of LW and CW. The crystal widths of CW were slightly smaller than those of LW and OW. The CW and LW showed similar FT-IR spectra in juvenile and mature wood, whereas some peaks from lignin disappeared in the juvenile and mature wood of OW. The MFA of Pinus densiflora was decreased with increasing growth ring number. The relative crystallinity from each part was increased with increasing growth rings, whereas the crystal width showed no radial variation. The FT-IR spectra from CW, LW, and OW in mature wood showed a smaller number of peaks compared to the juvenile wood. In conclusion, the CW, LW, and OW showed a distinct difference in the MFA, crystalline characteristics, and chemical compounds, wherein the MFA and relative crystallinity of CW, LW, and OW showed a radial variation.

The rare ginsenosides have superior pharmacological activity than the major ginsenosides. Rare ginsenosides are usually an intermediate product of the ginsenoside biosynthesis pathway and do not accumulate in plants. Therefore, its application in medicine and functional foods is inhibited by the production amount. We developed an effective combinatorial biotechnology approach including large-scale production of ginseng adventitious root in plant bioreactor, hydrolysis of glycosidase combinations and immobilization of glycosidase. Firstly, we used 10 liters to 5 tons of plant bioreactor systems of different sizes to cultivate ginseng adventitious roots, and obtained large amounts of pesticide and heavy metal-free root materials with stable ginsenosides content. The biomass could be increased 30-fold within 60 days and the content of ginsenosides was similar to that of 5-years-old cultivated ginseng. Secondly, we screened out more than ten kinds of glycosidases according to the hydrolysis sites and compared the yield and hydrolysis efficiency of ginsenosides by several combinations of enzymes. Afterwards, a variety of effective combinations were obtained, including Bglsk+Bglmm, BglPm+Bgp1, BglSk+Bgp1, BglSk+BglPm+BgpA. 3g total ginseng saponins extracted from adventitious roots in a 10L bioreactor were converted into more than ten kinds of rare ginsenosides after the enzymes treatment, such as PPD, Rh2, Rg3 and CK. The contents are 336.42 mg, 326.61 mg, 138.54 mg and 279.27 mg, respectively. Thirdly, two kinds of β-glycosidases, BglPm and Bgp1, were immobilized on the hollow fiber membrane. After immobilization, the Km of BglPm and Bgp1 were remain unchanged, while the reaction rates were increased 3-fold and 5-fold, respectively. In the immobilized combination of two glycosidases, the yield of Rh2 was further increased to 511.72 mg. After 2 weeks of immobilization, the β-glycosidases activity remained above 80%. Our combinatorial biotechnology provides an efficient, low-cost, pollution-free and reusable method for large-scale production of diverse rare ginsenosides.

Cellulose is one of the most abundant organic compounds in earth. Therefore, it can be employed as an eco-friendly and sustainable material in a wide range of applications. Especially, cellulose nanocrystals (CNCs) that have a length of several hundred nanometers have been investigated in many research fields owing to their various excellent characteristics. However, there are only few reports on the use of CNCs in organic semiconductor devices. Thus, CNCs are very promising material that can exhibit useful properties in electronic devices. In this study, we fabricated organic resistive switching devices using a mixture of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) conducting polymer and CNCs. The PEDOT:PSS-CNCs mixture film was inserted between ITO and MoO3/Al electrodes. The change in current density-voltage curves by various concentrations of CNC in PEDOT:PSS were measured and the electrical parameters of PEDOT:PSS and PEDOT:PSS-CNCs devices were compared. In addition, the electronic structure of PEDOT:PSS-CNC film was determined using X-ray photoelectron spectroscopy. Through these results, we discuss the mechanism of resistive change by CNCs.

Oil palm (Elaeis guineensis) empty fruit bunches (EFB) is solid wastes derived from palm oil production which has not been utilized optimally, hence it is considered as a low economic value resource. This biomass resource can be converted into bioenergy through torrefaction process. Torrefaction is a mild pyrolysis at temperatures ranging between 200 and 300°C and it is generally performed under inert (non-oxidative) atmosphere. The aim of this paper was to compare non-oxidative and oxidative torrefaction processes applying to EFB pellets. Non-oxidative torrefaction was conducted by using a pilot plant namely Counter-Flow Multi Baffle Dryer/Pyrolizer (COMB) with a capacity of 20 kg/h. COMB is a multi-station high moisture flow baffle plate dryer for drying, torrefaction, and pyrolysis. COMB has simple, flexible and movable baffles that could perform drying or torrefaction within a short residence time of up to 5 min, with low gas to solid ratio, and constant temperature difference along the column. Torrefaction with COMB was conducted at 280°C with a residence time of 4 min. Oxidative torrefaction was conducted under air atmosphere in an electric furnace at 280°C with a residence time of 20 min. The results showed a decrease in the equilibrium moisture content (EMC) with a lower EMC observed in samples treated with oxidative torrefaction. The results also showed that torrefaction caused an improvement of hygroscopic property that could make biomass more stable against chemical oxidation and microbial degradation, hence self-heating and auto-ignition during storage could be prevented. The heating value of biomass increased after torrefaction. Non-oxidative torrefaction with COMB reactor resulted in a heating value of 17.90 MJ/kg, which is comparable with the results of oxidative torrefaction (with longer residence time) of 18.28 MJ/kg. The results proposed that torrefaction using COMB reactor could provide a great improvement in the quality of the bioenergetic properties of biomass that make torrefied biomass particularly suitable for cofiring in power plants and as a feedstock for gasification.

Korea has abundant and diverse forest resources with 63.6 percent of forest area in total land area. However, Korea relies on imports for more than 80 percent of wood demand in industrial needs due to the poor quality of locally produced wood resources. As one of the alternatives, it is possible to suggest stable supply of timber resources through overseas plantation, In this study, we investigated the possibility of utilization less known Indonesian wood species by understanding of basic wood properties such as anatomical, physical and mechanical properties. In this study, we investigated the wood quality of three Indonesian species that collected from Gunung walat in Bogor, such as Bisbul (Diospyros blancoi), Bungur (Lagerstroemia speciosa), and Salam (Eugenia polyanthha). All of samples were superior than domestic wood species in aspect of density and strength, nevertheless, while Bisbul and Salam were vulnerable in shrinkage, and Bunger shows stable in dimensional change. Therefore, Bisbul and Salam can be used in places that require high strength but do not require significant dimensional stability. and Bunger has classified as promising species for plantation if some more research of genetic field is carried for diameter improvement.

Kluyveromyces marxianus 17555ΔURA3 strain was engineered by random integration of xylose metabolic pathway. Dual expression cassettes (KmXYL1-KmXYL2, KmXYL1-KmXYL3 and KmXYL2-KmXYL3) for xylose utilization were constructed using pJSKm316-GPD vector. Fermentation experiments were performed under different aeration conditions (micro aerobic or high aerobic) by engineered K. marxianus strains (17555-DC12, 17555-DC13 and 17555-DC23) at 30oC. The parental strain consumed 26.13 g/L xylose and produced 7.36 g/L xylitol and 2.05 g/L ethanol at micro aerobic conditions. In contrast, K. marxianus 17555-DC12 strain consumed 44.39 g/L xylose and produced 19.73 g/L xylitol and 5.72 g/L ethanol for 96 h. At high aerobic conditions, the parental strain consumed 31.01 g/L xylose and produced 9.62 g/L xylitol and 1.86 g/L ethanol. On the other hand, K. marxianus 17555-DC12 consumed 38.52 g/L xylose and produced 15.52 g/L xylitol and 5.10 g/L and ethanol for 72 h. Xylose consumption rate, xylitol production and ethanol production rates from K. marxianus 17555-DC12 were improved by 24%, 61% and 174%, respectively as compared to those from the parental strain at high aerobic conditions.

Generally, bacteriocins are known as antimicrobial proteins produced from lactic acid bacteria. Bacteriocins induce the cell death of bacteria through several mechanisms such as forming holes in the cell membrane. These bacteriocins are considered as substitutes for conventional antibiotics causing antibiotic resistance problems. We isolated a lactic acid bacteria showing antimicrobial activity, and identified this strain as Lactobacillus plantarum BG0001 through 16S RNA sequencing. After L. plantarum BG0001 was cultured in MRS medium for 24 hours, culture broth was separated by centrifugation and concentrated to 20-fold by freeze drying. Using this concentrated culture broth, disk diffusion test and minimal inhibition concentration (MIC) test were performed with Bacillus cereus for verifying antimicrobial activity. According to disk diffusion test, the sizes of clear zone were gradually and proportionally increased as increase as the concentration of concentrated culture broth. As a result of MIC test, the growth of B. cereus was highly inhibited from the concentration of 12.79 mg/mL bacteriocin produced by L. plantarum BG0001.

Kluyveromyces marxianus 17555-DF-33 was engineered by integration of KmXYL1 and KmXYL2 genes into K. marxianus 17555ΔURA3 by random integration method. After random integration of KmXYL1 and KmXYL2 genes, K. marxianus 17555-DF-33-14 strain was isolated for efficient ethanol production from xylose, through a directed evolutionary approach. In order to optimize fermentation conditions, agitation and medium pH conditions were varied using bioreactor. Xylose consumption rate, xylitol production rate and ethanol production rate were 1.50 g/L∙h, 0.73 g/L∙h and 0.02 g/L∙h, respectively at 600 rpm. However, ethanol production rate was 6 fold higher at 500 rpm (0.12 g/L∙h) than that from 600 rpm. In addition, when pH was controlled by 5.0, xylitol and ethanol concentration were increased, but cell growth was decreased. The optimum fermentation conditions were 500 rpm and pH 5.0 for ethanol production. Under the optimum conditions, xylose consumption rate, xylitol production rate and ethanol production rate were 1.05 g/L∙h, 0.43 g/L∙h and 0.13 g/L∙h, respectively.