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Alkaline wet oxidation of lignin was performed to study the effect of Cu-Mn mixed oxide catalysts on the production of vanillin at between 120–180 °C using H2O2 as an oxidizing agent. The mixed oxide catalysts were prepared by a sol-gel method with mixing ratios of Cu to Mn between 0.25 and 0.75 and characterized by XRD, XPS, N2-physisorption, SEM-EDS, and H2-TPR. The XRD and N2-physisorption analyses showed a non-stoichiometric spinel structure (Cu1.5Mn1.5O4) and a relatively high BET surface area of the mixed oxides compared with pure Cu and Mn oxides, respectively. In addition, the Cu-Mn mixed oxide catalysts exhibited better redox properties and a higher catalytic performance for lignin oxidation to vanillin and other aromatic oxygenates. Higher Cu contents in the mixed oxide catalysts promoted the over-oxidation of vanillin producing vanillic acid along with the formation of more surface oxygen species on the catalyst surface. Finally, a possible reaction pathway for the catalytic conversion of lignin to vanillin was proposed.

Research on producing medium- and long-chain hydrocarbons as drop-in biofuels has recently accelerated. In addition, lipids are emerging as precursors for biofuel production, and thus, microbial lipid production utilizing agrowastes is becoming a feasible platform technology. Nonetheless, microorganisms are often inhibited by furan aldehydes in biomass-derived hydrolysates. Accordingly, this study aimed to develop oleaginous yeast strains that can tolerate furan aldehydes for producing lipids as biofuel precursors. Rhodosporidium toruloides was selected as the target for adaptive laboratory evolution. The evolved strain, which was obtained from 16 rounds of subcultures, showed a 2.5-fold higher specific growth rate than the wild-type strain in the presence of furan aldehydes and slightly higher lipid production in rice straw hydrolysate. The results discussed in this study provide insights into the production of lipid production by oleaginous yeast utilizing agrowastes as feedstock to obtain drop-in biofuels and contribute to feasible strategies to address climate crises.

In the bioproduction of glutaric acid, an emerging bioplastic monomer, α-ketoglutaric acid (α-KG) is required as an amine acceptor for 4-aminobutyrate aminotransferase (GabT)-driven conversion of 5-aminovalerate (5-AVA) to glutarate semialdehyde. Herein, instead of using expensive α-KG, an indirect α-KG supply system was developed using a relatively cheap alternative, monosodium glutamate (MSG), for l-glutamate oxidase (Gox)-based whole-cell conversion. Using 200 mM 5-AVA and 30 mM MSG initially with Gox, 67.1 mM of glutaric acid was produced. By applying the stepwise feeding strategy of MSG, the glutaric acid production capability was increased to 159.1 mM glutaric acid with a conversion yield of 79.6%. In addition, a buffer-free one-pot reaction from l-lysine was also applied in a 5 L bioreactor to evaluate its industrial applicability, resulting in a conversion yield of 54.2%. The system developed herein might have great potential for the large-scale, economically feasible production of glutaric acid by whole-cell conversion.

With concerns over global warming and climate change, many efforts have been devoted to mitigate atmospheric CO

Bio-jet fuel range alkanes were prepared by catalytic deoxygenation reaction of non-edible acid oils with no added hydrogen. A WOx[6]/Pt[1.6]/TiO2 was used for the deoxygenation of stearic acid and Jatropha fatty acid derived from Jatropha oil by hydrolysis. Tungsten addition to the Pt/TiO2 showed remarkably enhanced performance, a degree of deoxygenation of 86%, which is more than two times higher than that of the Pt/TiO2, even though the WOx/TiO2 had almost no activity for deoxygenation reaction. The enhanced Pt-related hydrogen uptake, measured by H2-TPR, and XPS analysis showed the intimate contact of tungsten with Pt nanoparticles supported on TiO2. This tight contact allows for easier C C cleavage over Pt nanoparticles and this is assisted by the strong bonding between tungsten and oxygen in the reactant, resulting in more C17 hydrocarbon production on the WOx/Pt/TiO2.

The recalcitrance of petroleum-based plastics causes severe environmental problems and has accelerated research into production of biodegradable polymers from inexpensive and sustainable feedstocks. Various microorganisms are capable of producing Polyhydroxybutyrate (PHB), a representative biodegradable polymer, under nutrient-limited conditions, among which CO2-utilizing microorganisms are of primary interest. Herein, we discuss recent progress on bacterial strains including proteobacteria, purple non-sulfur bacteria, and cyanobacteria in terms of CO2-containing carbon sources, PHB-production capability, and genetic modification. In addition, this review introduces recent technical approaches used to improve PHB production from CO2 such as two-stage bioprocesses and bioelectrochemical systems. Challenges and future perspectives for the development of economically feasible PHB production are also discussed. Finally, this review might provide insights into the construction of a closed-carbon-loop to cope with climate change.

Endo-1,4-β-xylanase is one of the most important enzymes employed in biorefineries for obtaining fermentable sugars from hemicellulosic components. Herein, we aimed to improve the catalytic performance of Bacillus circulans xylanase (Bcx) using a structure-guided rational design. A systematic analysis of flexible motions revealed that the R49 component of Bcx (i) constrains the global conformational changes essential for substrate binding and (ii) is involved in modulating flexible motion. Site-saturated mutagenesis of the R49 residue led to the engineering of the active mutants with the trade-off between flexibility and rigidity. The most active mutant R49N improved the catalytic performance, including its catalytic efficiency (7.51-fold), conformational stability (0.7 °C improvement), and production of xylose oligomers (2.18-fold higher xylobiose and 1.72-fold higher xylotriose). The results discussed herein can be applied to enhance the catalytic performance of industrially important enzymes by controlling flexibility.

Given that (i) levulinic acid (LA) is one of the most significant platform chemicals derived from biomass and (ii) 4-hydroxyvaleric acid (4-HV) is a potential LA derivative, the aim of this study is to achieve chemoenzymatic valorization of LA, which was obtained from agricultural wastes, to 4-HV. The thermochemical process utilized agricultural wastes (i.e., rice straw and corncob) as feedstocks and successfully produced LA, ranging from 25.1 to 65.4 mM. Additionally, formate was co-produced and used as a hydrogen source for the enzymatic hydrogenation of LA. Finally, engineered 3-hydroxybutyrate dehydrogenase from Alcaligenes faecalis (eHBDH) was applicable for catalyzing the conversion of agricultural wastes-driven LA, resulting in a maximum concentration of 11.32 mM 4-HV with a conversion rate of 48.2%. To the best of our knowledge, this is the first report describing the production of 4-HV from actual biomass, and the results might provide insights into the valorization of agricultural wastes.

Facial nerves are frequently injured during cosmetic or other types of facial surgery. However, information on the genes involved in the damage and recovery of the facial nerves is limited. Here, we aimed to identify the genes affected by facial nerve injury and repair using next-generation sequencing. We established a rat axotomy model and a parallel epineurial neurorrhaphy model, in which gene expression was analyzed from 3 days to 8 weeks after surgery. We discovered that ARRB1, SGK1, and GSK3B genes associated with neuronal cell death were upregulated in the axotomy model. In contrast, MFRP, MDK, and ACE genes involved in neural recovery and regeneration exhibited higher expression in the neurorrhaphy model. In the present study, the analysis of the big data obtained from the next-generation sequencing (RNA-seq) technology reveals that the expression of genes involved in neuronal cell death is induced during nerve damage, and those associated with neural recovery are more abundantly expressed during repair processes. These results are considered to be useful for the establishment of the treatment of related diseases and basic research in various neuroscience fields by utilizing damage and recovery mechanism of facial nerves.

The catalytic deoxygenation reaction of crude Jatropha oil (CJO) was carried out to produce oxy-free hydrocarbons in assistance with hydrogen in-situ produced from formic acid solution (30%) and addition effect of formic acid was discussed on the deoxygenation reaction and product distribution. Mixing of formic acid with reactant yielded higher oil conversion and higher selectivity to normal hydrocarbon (mainly C 15 and C 17 ) than those of the other cases (no mixing or water addition). Total surface area and total pore volume of used catalysts in the batch reactor followed the order Pd/C–formic acid solution > Pd/C–water > Pd/C–no co-reactant under constant conditions. Moreover, significantly higher degree of deoxygenation with a high initial resistance to catalyst deactivation was observed on Pd/C catalyst in the presence of formic acid during the continuous catalytic reaction. This means that addition of formic acid solution as the hydrogen donor is favorable the deoxygenation reaction and the initial deactivation of catalyst. As results of continuous deoxygenation reaction using the mixture of oil and formic acid, normal hydrocarbon in the liquid product was main product, about 97%, and the degree of deoxygenation was about 99.5%.

The electrochemical conversion of CO2 can include renewable surplus electricity storage and CO2 utilisation. This review focuses on the microbial CO2 electrobiorefinery based on microbial electrosynthesis (MES) which merges electrochemical and microbial conversion to produce biofuels and higher-value chemicals. In this review, recent developments are discussed about bioelectrochemical conversion of CO2 into biofuels and chemicals in MES via microbial CO2-fixation and electricity utilisation reactions. In addition, this review examines technical approaches to overcome the current limitations of MES including the following: engineering of the biocathode, application of electron mediators, and reactor optimisation, among others. An in-depth discussion of strategies for the CO2 electrobiorefinery is presented, including the integration of the biocathode with inorganic catalysts, screening of novel electroactive microorganisms, and metabolic engineering to improve target productivity from CO2.

Formate dehydrogenase (FDH) has been considered as a nearly irreversible biocatalyst for catalyzing formate oxidation to CO2 for a long time. However, recent research clearly proved that certain FDHs, mainly NAD+-linked/metal (either W- or Mo-) containing enzymes, are capable of reversibly interconverting CO2 and formate, thereby having a significant role as a non-photosynthetic CO2 utilizing enzyme. We, herein, summarize and discuss not only recently discovered CO2 reduction activities and structure-based enzyme engineering reinforcing the CO2 reduction activity but also applications for a CO2 refinery including electroenzymatic approaches, whole-cell biocatalytic systems, and multi-enzyme cascade reactions in detail. Especially, this review concentrates on as well as comprehensively discusses recent progress. Furthermore, innovative results discussed herein might provide revelaratory insights applicable for constructing a feasible CO2 refinery system that utilizes CO2 as an abundant, cheap, and sustainable feedstock in order to produce value-added fuels and chemicals.

Due to climate change, recent research interests have increased towards CO2 utilization as a strategy to mitigate the atmospheric CO2 level. Herein, we aimed to explore formate dehydrogenases (FDHs) from chemoautotroph to discover an efficient and O2-tolerant biocatalyst for catalyzing the CO2 reduction to a versatile formate. Through genome-mining and phylogenetic analysis, the FDH from Rhodobacter aestuarii (RaFDH) was newly discovered as a promising O2-tolernat CO2 reductase and was successfully expressed in Escherichia coli. In this study, the optimum conditions and turnover rates of RaFDH were examined for CO2 reduction and formate oxidation. In particular, the RaFDH-driven CO2 reduction far surpassed the formate oxidation with a turnover rate of 48.3 and 15.6 min−1, respectively. The outstanding superiority of RaFDH towards CO2 reduction can be applicable for constructing a feasible electroenzymatic system that produce a versatile formate from CO2 as a cheap, abundant, and renewable resource.

In this study, we aimed to demonstrate the feasibility of the application of biocompatible liquid type fluorescent carbon nanodots (C-paints) to microalgae by improving microalgae productivity. C-paints were prepared by a simple process of ultrasound irradiation using polyethylene glycol (PEG) as a passivation agent. The resulting C-paints exhibited a carbonyl-rich surface with good uniformity of particle size, excellent water solubility, photo-stability, fluorescence efficiency, and good biocompatibility ( 20% higher than the control cell content). A C-paints concentration of 1–10.0 mg mL−1 induced an approximately >1.8 times higher astaxanthin content than the control cells. The high light delivery effect of non-cytotoxic C-paints was applied as a stress condition for H. pluvialis growth and was found to play a major role in enhancing productivity. Notably, the results from this study are an essential approach to improve astaxanthin production, which can be used in various applications because of its therapeutic effects such as cancer prevention, anti-inflammation, immune stimulation, and treatment of muscle-soreness.

This article presents a preliminary result on deciding whether to use simulated moving-bed (SMB) technology in a conventional petrochemical complex (cPCC) to increase olefins and aromatics production. A process model including an SMB unit, naphtha hydro-treating (NHT), naphtha thermal cracking (NTC), and naphtha catalytic reforming (NCR) was constructed to evaluate the economic feasibility of the retrofit petrochemical complex (rPCC) with the SMB unit for 2500 kt/yr naphtha treatment. The chemical reaction kinetics of NTC and NCR were used to estimate the increase of olefins and aromatics production. The incremental total capital investment for the SMB and additional NHT areas, estimated by the factorial method, was 97.5 $M. The incremental total production cost concerning utility and fixed costs was 25 $M/yr. It was found that the rPCC has economic benefits, because the return on investment (ROI) after tax, payback period (PBP), and internal rate of return (IRR) are 18%, 3.7 yr, and 20%, respectively. The SMB recovery of n-paraffins was most influenced on ROI and IRR in sensitivity analysis.

In order to meet company needs, various models of naphtha price forecasting and optimization models of average naphtha purchase price have been developed. However, these general models are limited in their ability to predict future trends as they only include quantitative data. Furthermore, naphtha price predictions based on fluctuation trends have not been published in the literature. Thus, we developed a system dynamics (SD) model considering time-series data, mathematical formulations, and qualitative factors. The results obtained from our model were compared with the published literature. The best result of the SD is the European naphtha forecasting price model, and the forecasting accuracy percentage shows 92.82%. Furthermore, a nonlinear programming (NLP) model was developed to optimize the purchase price by considering the naphtha price of the forecasting models. In addition, the average optimization value was approximately 45.07 USD/ton cheaper than that of the heuristic approach.

Recently, biofuels and nutraceuticals produced from microalgae have emerged as major interests, resulting in intensive research of the microalgal biorefinery process. In this paper, recent developments in cell-wall disruption and extraction methods are reviewed, focusing on lipid and astaxanthin production from the biotechnologically important microalgae Chlorella and Haematococcus, respectively. As a common, critical bottleneck for recovery of intracellular components such as lipid and astaxanthin from these microalgae, the composition and structure of rigid, thick cell-walls were analyzed. Various chemical, physical, physico-chemical, and biological methods applied for cell-wall breakage and lipid/astaxanthin extraction from Chlorella and Haematococcus are discussed in detail and compared based on efficiency, energy consumption, type and dosage of solvent, biomass concentration and status (wet/dried), toxicity, scalability, and synergistic combinations. This report could serve as a useful guide to the implementation of practical downstream processes for recovery of valuable products from microalgae including Chlorella and Haematococcus.

The catalytic conversion of non-edible oil was carried out over a Pd-based zeolite catalyst in a single-step process (SSP) with no added hydrogen to examine the possibility of the direct production of hydrocarbons in the ranges of jet fuel. The conversion of stearic acid, a model fatty acid compound, reached 100% and the proportion of hydrocarbons in the jet-fuel range was 69.3% over a Pd/beta-zeolite catalyst at 270 °C in a SSP. In addition, the obtained jet-fuel was composed of normal, isomer, and aromatic hydrocarbons, all of which were oxygen-free compounds. Through the catalytic conversion of raw materials, waste soy bean oil (SBO) and palm fatty acid distillate (PFAD), a high-quality jet-fuel product was also obtained in a SSP. The degree of oxygen removal was approximately 95% for the conversions of SBO and PFAD.

Microalgae, as biodiesel feedstock, are promising renewable energy sources that can be continuously developed into the future. Because recovery of microalgal lipid from dry microalgae incurs high costs, particularly in the dewatering process, wet extraction has been suggested as an attractive alternative approach. In the present study, the feasibility of a sonication-assisted homogenization system for lipid extraction from Chlorella vulgaris was evaluated. To that end, lipid-extraction performance, according to reaction time, cell concentration, and solvent type, was investigated. The initial fatty acid content of the C. vulgaris was 360.2 mg/g cell. The combination of sonication and homogenization broke up the microalgal cell walls, thereby facilitating lipid recovery. By this method, the lipid-recovery yields were increased compared with that by solo use of either homogenization or sonication. Further, chloroform-methanol, as a recovery solvent, significantly enhanced lipid recovery (237.5 mg lipid/g cell at 60 min reaction time) relative to hexane (152.0 mg lipid/g cell at 60 min reaction time).

The objective of this study is to investigate the effect of the normal paraffins ( n -paraffins) separation by the simulated moving-bed (SMB) on reaction kinetics of the naphtha thermal cracking (NTC) and catalytic reforming (NCR) for the olefins and aromatics production, respectively. First a process simulation of the SMB unit integrated to the petrochemical complex (PCC) was performed. Chemical reaction kinetics of NTC and NCR were proposed and validated. And a retrofit PCC with the SMB unit (rPCC) was compared to a conventional PCC (cPCC) in terms of products composition, flow rate, and energy consumption. It was found that olefins and aromatics yields of NTC and NCR can increase by 14 wt% (41 kt/yr) and 11 wt% (127 kt/yr) for the naphtha capacity of 2475 kt/yr, respectively. However, the total energy consumption of rPCC increased by about 67.8 MW (or 25%) because of the desorbent recovery in the SMB unit.

In this study, pre-biodiesel-production lipid extraction from microalgae (Chlorella vulgaris) was performed. The yield-enhancing effects of ionic liquid blends on the lipid extraction were investigated. The initial fatty acids content of the C. vulgaris was 292.2 mg/g cell. The lipid extraction yield using single ionic liquids was compared with the yield obtained with organic solvents and ionic liquid mixtures, respectively. The yield by hexane–methanol solvent was 185.4 mg/g cell. Among the 12 ionic liquids, 1-ethyl-3-methyl imidazolium acetate, 1-ethyl-3-methyl imidazolium diethylphosphate, 1-ethyl-3-methyl imidazolium tetrafluoroborate, and 1-ethyl-3-methyl imidazolium chloride showed high (>200.0 mg/g cell) lipid extraction yields. Although the yields of 1-ethyl-3-methyl imidazolium ethyl sulfate and 1-ethyl-3-methyl imidazolium thiocyanate were only 60.5 and 42.7 mg/g cell, respectively, the yield for their mixture (weight ratio of 1:1) was improved to 158.2 mg/g cell. Similarly, whereas the lipid extraction yield of 1-ethyl-3-methyl imidazolium hydrogen sulfate was just 35.2 mg/g cell, that for its mixture with 1-ethyl-3-methyl imidazolium thiocyanate (weight ratio of 1:1) was boosted to 200.6 mg/g cell. Overall, the synergistic effects of the ionic liquid mixtures with different anions improved the lipid extraction yield of C. vulgaris.

The present work describes the development of a two-dimensional mathematical model of a pilot-scale fixed-bed reactor for Fe-based Fischer–Tropsch synthesis to evaluate the effect of tube diameter on temperature profile and catalyst performance. The entire chain lengths of the hydrocarbon products were lumped to form several representative components, and the apparent kinetic parameters for the reaction rates were estimated. The effectiveness of the developed model was corroborated by the comparison of temperature profiles, conversion, and selectivities between experimental and simulated results. The increase of tube diameter in the simulation showed that temperature increased in both the radial and the axial directions owing to the low radial heat transfer rate and the low heat transfer area, respectively. Finally, the specified diameter in the present study maintained the temperature below the threshold value and the methane selectivity below 10%.

A series of Pt/Sn/M/γ-Al2O3 catalysts with different third metal (M = Zn, In, Y, Bi, and Ga) were prepared by a sequential impregnation method for use in the direct dehydrogenation of n-butane to n-butene and 1,3-butadiene. In the direct dehydrogenation of n-butane, Pt/Sn/Zn/γ-Al2O3 catalyst showed the best catalytic performance. Catalytic performance decreased in the order of Pt/Sn/Zn/γ-Al2O3 > Pt/Sn/In/γ-Al2O3 > Pt/Sn/γ-Al2O3 > Pt/Sn/Y/γ-Al2O3 > Pt/Sn/Bi/γ-Al2O3 > Pt/Sn/Ga/γ-Al2O3. The catalytic performance increased with increasing metal–support interaction and Pt surface area of the catalyst.

In Korea, ship collisions represent the majority of marine accidents and are substantially more likely in port areas where ship traffic is dense. To improve the safe navigation of vessels, the Korea Maritime Safety Audit (KMSA) has been conducting maritime traffic flow evaluations based on the Environmental Stress (ES) model since 2009. The ES model quantifies the subjective stress felt by the navigator; however, it does not reflect the relative bearing between ships. Risk assessment models using the ship domain are designed to consider the conditions of a potential encounter with a target ship and the possibility of avoidance action. However, even if the target ship does not invade the domain of the own ship, collision may occur at the closest point of approach (CPA). Therefore, in this study, the Collision RIsk (CoRI) model which moves the existing ship domain to the CPA is applied to compare the collision risk according to the navigator's awareness of the vessel encounter conditions. The results demonstrate that the CoRI model is a better risk assessment method than the ES model because it sensitively reflects the risks due to collision avoidance action, such as course alteration and speed changes.

In this study, lipid extraction from Chlorella vulgaris was performed by using mixtures of molten salt and ionic liquid. The yield-enhancing effects of blending of molten salt with ionic liquid were investigated. Among the three molten salts (Zn(NO 3 ) 2 ·6H 2 O, Mg(ClO 4 ) 2 ·6H 2 O, and FeCl 3 ·6H 2 O), FeCl 3 ·6H 2 O showed a high lipid extraction yield (113.0 mg/g cell) and good reaction performance. When FeCl 3 ·6H 2 O was mixed with [Emim]OAc (5:1, w/w), the lipid extraction yield increased to 227.6 mg/g cell, a performance similar to that of single [Emim]OAc (218.7 mg/g cell). When lipid was extracted by the FeCl 3 ·6H 2 O/[Emim]OAc mixture at a 5:1 (w/w) blending ratio, 90 °C temperature, and 1 h duration, the fatty acid content of the extracted lipid was 981.7 mg/g lipid, indicating less than 2% impurity. The lipid extraction from C . vulgaris was improved by the synergistic effects of molten salt and ionic liquid with different ions.

Repetitive transcranial magnetic stimulation (rTMS) is used to treat neurological diseases such as stroke and Parkinson's disease (PD). Although rTMS has been used clinically, its underlying therapeutic mechanism remains unclear. The objective of the present study was to clarify the neuroprotective effect and therapeutic mechanism of rTMS in an animal model of PD. Adult Sprague-Dawley rats were unilaterally injected with 6-hydroxydopamine (6-OHDA) into the right striatum. Rats with PD were then treated with rTMS (circular coil, 10 Hz, 20 min/day) daily for 4 weeks. Behavioral assessments such as amphetamine-induced rotational test and treadmill locomotion test were performed, and the dopaminergic (DA) neurons of substantia nigra pas compacta (SNc) and striatum were histologically examined. Expression of neurotrophic/growth factors was also investigated by multiplex ELISA, western blotting analysis and immunohistochemistry 4 weeks after rTMS application. Among the results, the number of amphetamine-induced rotations was significantly lower in the rTMS group than in the control group at 4 weeks post-treatment. Treadmill locomotion was also significantly improved in the rTMS-treated rats. Tyrosine hydroxylase-positive DA neurons and DA fibers in rTMS group rats were greater than those in untreated group in both ipsilateral SNc and striatum, respectively. The expression levels of brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor, platelet-derived growth factor, and vascular endothelial growth factor were elevated in both the 6-OHDA-injected hemisphere and the SNc of the rTMS-treated rats. In conclusion, rTMS treatment improved motor functions and survival of DA neurons, suggesting that the neuroprotective effect of rTMS treatment might be induced by upregulation of neurotrophic/growth factors in the PD animal model.

Microalgae biorefinement has attracted in intensive academic and industrial interest worldwide for its potential to replace petrol biofuels as economically and environmentally advantageous alternatives. However, harvesting and lipid extraction remain as critical and difficult issues to be resolved. In the present study, four amino-groups functionalized organic-nano clays were prepared. Specifically, Mg or Al or Ca backboned and covalently linked with 3-aminopropyltriethoxysilane or 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane by sol-gel reaction under ambient conditions, resulted in Mg-APTES clay, Al-APTES clay, Ca-APTES clay, and Mg-N3 clay, respectively. Each organic-nanoclay was utilized for lipid extraction from wet microalgae biomass. As a result, the lipid-extraction efficiency of paste docosahexaenoic acid (DHA)-rich Chlorella sp. with low lipid content was high, while one of paste oleaginous Chlorella sp. with high lipid content was relatively low. Despite the low lipid-extraction efficiencies in all of the wet microalgae biomass, the conversion of the extracted lipids' fatty acids to biodiesel was nearly 100%.

In this study, 4-methylmorpholine N-oxide (NMMO) and four ionic liquids were compared to determine the most suitable type for use in pretreatment of oil palm empty fruit bunch (EFB) to enhance enzymatic digestibility and obtain maximal fermentable sugar (glucose). Four types of ionic liquids, namely, 1-ethyl-3-methyl imidazolium acetate ([Emim]OAc), 1-butyl-3-methyl imidazolium chloride ([Bmim]Cl), tributyl methyl ammonium methylsulfate (MTBS), and 1-ethyl-3-methyl imidazolium diethylphosphate ([Emim]DEP), were used. The effects of pretreatment temperature and time on the enzymatic digestibility of EFB were examined. Among NMMO and four ionic liquids, NMMO and [Emim]OAc, showing high enzymatic digestibility, were found to be most effective for EFB pretreatment. The enzymatic digestibility of NMMO-pretreated EFB increased as pretreatment temperature and time increased. After [Emim]OAc pretreatment, the crystallinity index of EFB decreased, due to the conversion of crystalline cellulose to amorphous cellulose, and the enzymatic digestibility thereby was increased to 96.6% at 110 °C for 2 h.

X-Mg3(VO4)2/MgO–ZrO2 catalysts were prepared by a wet impregnation method with a variation of vanadium content (X = 2.8, 4.2, 5.6, 9.0, and 11.2 wt%), and they were applied to the oxidative dehydrogenation of n-butane. Effect of oxygen capacity and acidity of Mg3(VO4)2/MgO–ZrO2 catalysts on the catalytic performance in the oxidative dehydrogenation of n-butane was investigated. Experimental results revealed that oxygen capacity and acidity of catalyst were closely related to the catalytic performance in the oxidative dehydrogenation of n-butane. It was found that the catalytic performance of X-Mg3(VO4)2/MgO–ZrO2 catalysts increased with increasing oxygen capacity and with increasing acidity of the catalyst.

Eight-zone para-xylene (PX) simulated moving-bed (SMB) involves three flushing sequences to prevent purity deterioration caused by SMB bed-lines connecting a rotary valve to beds. Beside the recycle flow from the last zone to the first, the extract fluid trapped in bed-line (BL) is fed back to one bed ahead of the extract bed in accord with the line flushing ( LF ) and secondary flushing ( SF i ), forming an internal recycle flow. Both LF and SF i form the closed loop to increase purity and recovery, while the tertiary flushing ( TF o ) works somewhat independently of the other flushing streams for recovery enhancement. Thus, a two-level optimization strategy was proposed to identify optimum bed-configuration and flushing flow rates of LF , SF i and TF o . This study also examined how axial dispersion inside BL influences recovery and purity. The paper shows that the annual profit of the 8-zone SMB increases by 50 tons of PX/year over that of 7-zone SMB.

Crude canola oil (CCO) contains about 100–300 ppm of phospholipids, which have shown negative effects on biodiesel/buffer solution phase separation, resulting in low biodiesel production yield. Therefore, phospholipids should be removed before transesterification by a degumming process for efficient production of biodiesel. In this study, two-step enzymatic processes (degumming and transesterification) were carried out for the production of biodiesel from CCO. Degumming of CCO was performed using phospholipase A2 as a degumming reagent. The initial phospholipid content was reduced to less than 5 ppm by enzymatic degumming. The effects of three formulations of enzyme catalyst on the efficiency of transesterification were investigated. As a result, conversion rates of degummed CCO to fatty acid methyl esters (FAME) were 68.56%, 70.15%, and 84.25%, respectively. Lipase formulation composed of a 1:1 (vol:vol) enzyme mixture of Rhizopus oryzae and Candida rugosa showed the best performance among those tested. In order to recover and reuse the lipase catalyst efficiently, a 1:1 enzyme mixture of R. oryzae and C. rugosa was immobilized on silica gel. The immobilized lipase was used in subsequent transesterification optimization experiments. Optimization of transesterification was performed by response surface methodology (RSM). A total of 20 experiments based on RSM were carried out, and the optimal reaction conditions appeared to be 24.4% (w/w) immobilized catalyst, 13.5% (w/w) buffer solution, and 15.8% (w/w) methanol based on oil mass. Conversion rate of degummed CCO to FAME was determined to be 88.9% under optimal conditions.

MgO–ZrO 2 supports with different Mg:Zr ratios (16:1, 8:1, 4:1, 2:1, and 1:1) were prepared by a gel-oxalate co-precipitation method, and Mg 3 (VO 4 ) 2 /MgO–ZrO 2 catalysts were then prepared by a wet impregnation method. The prepared catalysts were applied to the oxidative dehydrogenation of n-butane to n-butene and 1,3-butadiene. Experimental results revealed that oxygen capacity and acidity of the catalyst were closely related to the catalytic performance. Among the catalyst tested, Mg 3 (VO 4 ) 2 /MgO–ZrO 2 (4:1) catalyst, which retained the largest oxygen capacity and acidity, exhibited the best catalytic performance in the oxidative dehydrogenation of n-butane.

Vanadium-magnesium oxide (Mg3(VO4)2) catalysts supported on Al2O3, ZrO2, MgO, and CeO2 were prepared by a wet impregnation method, and they were applied to the oxidative dehydrogenation of n-butane. Effect of oxygen capacity and oxygen mobility of supported Mg3(VO4)2 catalysts on the catalytic performance in the oxidative dehydrogenation of n-butane was investigated. Experimental results revealed that large oxygen capacity of the catalyst was favorable for obtaining high catalytic activity at the initial stage of reaction, while facile oxygen mobility of the catalyst led to stable catalytic activity during the catalytic reaction in the oxidative dehydrogenation of n-butane.

Background Patients with umbilical hernias complicated by liver cirrhosis have an increased likelihood of complications following herniorrhaphy. The aim of this study was to investigate the clinical outcomes in patients with umbilical hernias complicated by liver cirrhosis. Methods Between 2001 and 2010, 44 patients were enrolled in this study. The comparison between non-operative and operative group was performed. Patients who underwent emergency versus elective surgery were also compared. Results Of the 44 patients, there were 33 men and 11 women. Thirty-one patients (70.5%) underwent surgery and 13 patients (29.5%) were treated conservatively. Overall morbidity and mortality rates following herniorrhaphy were 42% and 6.5%. The mean albumin level was significantly lower and total bilirubin, creatinine and mean model of end-stage liver disease score were significantly higher in non-operative group than in operative group. Combined resection was performed more frequently in the emergency group than in elective group. A significantly higher proportion of patients in emergency operation group had postoperative complications ( P = 0.01), especially ascites ( P = 0.02). The operative time and postoperative hospital stay were significantly shorter in the elective operation group than in emergency operation group. Conclusions Early, elective repair of umbilical hernias in cirrhotic patients should be advocated considering the hepatic reserve and patient's condition. Ascites control is the mainstay of post-operative management.

The current status of and challenges associated with bioenergy production and utilization in Korea are reviewed in this paper. Bioenergy (particularly transport biofuels) has emerged as a promising option for mitigating Korea's CO2 emissions and enhancing its energy security. Korea's limited biomass resources and the high cost of biofuels are the major barriers to achieving 2030's implementation targets. Efforts to identify new suitable biomass resources for biofuels production are ongoing and intensive. Aquatic biomasses including algae and plantation wastes collected in the Southeast Asia region have been found to have great potential as feedstocks. R&D on technologies that can more efficiently convert biomass materials to biofuels also are underway. It is expected that cost-effective biofuels will be in adequate supply from 2020 and that, by 2030, their use will contribute effectively to the realization of sustainable growth in Korea.

Biodiesel is a renewable fuel which can be produced through an esterification reaction. The cost of feedstock which resulted in that of biodiesel is a large problem to be resolved. Dark oil from industrial process can be a better alternative for biodiesel production because of its low price. In spite of this, the study of biodiesel production using the dark oil has not been reported. This study provides technical information and catalytic properties on this system. Among the several catalysts, WO 3 /ZrO 2 catalyst was the most effective catalyst in the esterification of the dark oil to fatty acid methyl esters (FAMEs). The catalytic reaction parameters were optimized that 20 wt.% WO 3 /ZrO 2 has a high FFA conversion of 96% at 150 °C, 0.4 g/ml (oil), 1:9 (oil to alcohol, molar ratio) and 2 h reaction time. The physical and chemical properties of the catalyst were characterized by XRD, Raman spectrometer, BET and NH 3 -TPD.

The current status and challenges associated with the production and utilization of cellulosic ethanol in Korea are reviewed in this paper. Cellulosic ethanol has emerged as a promising option for mitigating Korea's CO(2) emissions and enhancing its energy security. Korea's limited biomass resources is the most critical barrier to achieving its implementation targets for cellulosic ethanol. Efforts to identify new suitable biomass resources for cellulosic ethanol production are ongoing and intensive. Aquatic biomasses including macroalgae and plantation wastes collected in the Southeast Asia region have been found to have great potential as feedstocks for the production of cellulosic ethanol. R&D explorations into the development of technologies that can convert biomass materials to ethanol more efficiently also are underway. It is expected that cellulosic ethanol will be in supply from 2020 and that, by 2030, its use will have effectively reduced Korea's total gasoline consumption by 10%.

To maximize the production of biodiesel from soybean soapstock, the effects of water on the esterification of high-FFA (free fatty acid) oils were investigated. Oleic acid and high acid acid oil (HAAO) were esterified by reaction with methanol in the presence of Amberlyst-15 as a heterogeneous catalyst or sulfuric acid as a homogeneous catalyst. The yield of fatty acid methyl ester (FAME) was studied at oil to methanol molar ratios of 1:3 and 1:6 and reaction temperatures of 60 and 80 °C. The rate of esterification of oleic acid significantly decreased as the initial water content increased to 20% of the oil. The activity of Amberlyst-15 decreased more rapidly than that of sulfuric acid, due to the direct poisoning of acid sites by water. Esterification using sulfuric acid was not affected by water until there was a 5% water addition at a 1:6 molar ratio of oil to methanol. FAME content of HAAO prepared from soapstock rapidly increased for the first 30 min of esterification. Following the 30-min mark, the rate of FAME production decreased significantly due to the accumulation of water. When methanol and Amberlyst-15 were removed from the HAAO after 30 min of esterification and fresh methanol and a catalyst were added, the time required to reach 85% FAME content was reduced from 6 h to 1.8 h.

To produce biodiesel from high free fatty acid (FFA) oils, the esterification characteristics of two kinds of heterogeneous acid catalysts, Amberlyst 15 and Amberlyst BD20, were compared. When the FFA contents of oils were 50.0 and 99.8 wt%, the activity of Amberlyst 15 gradually decreased with recycling, whereas the activity of Amberlyst BD20 was maintained during recycling. The activity of Amberlyst 15 was inhibited by the water produced during the esterification process, but the activity of Amberlyst BD20 was not similarly affected by water. In images obtained with a scanning electron microscope (SEM), many pores were seen within the Amberlyst 15 catalyst, whereas Amberlyst BD20 showed few pores. Despite the fact that the pores of the catalyst play a role in increasing the number of active sites, Amberlyst BD20, which had fewer pores, was deemed to have more desirable performance in reducing the inhibition by water of the esterification of high FFA oils.

To improve the oxidation stability and the low temperature flow properties of a biodiesel mixture, the dependence of the oxidation stability and the cold filter plugging point (CFPP) on the fatty acid compositions was examined. Three different kinds of biodiesels, palm, rapeseed, and soybean biodiesels, were blended with the different weight ratios. The oxidation stability and the CFPP of the blended biodiesels had a close relationship with the compositions of the major fatty acid components. The oxidation stability of the blended biodiesels decreased as the total contents of the linoleic and linolenic acids increased. The correlation was obtained as Y=117.9295/X+2.5905 (0

Two closely related Arabidopsis mitogen-activated protein kinases (MAPKs), MPK3 and MPK6, are rapidly but transiently activated in plants exposed to ozone. Although the contribution of these MAPKs to control of redox stress has been examined extensively, it remains unclear whether the dual-specificity MKPs play an essential role in the regulation of these processes. To explore this question, specific knockdown of each of the five putative MKPs in Arabidopsis was performed, and the ozone sensitivity phenotype of each MKP-suppressed line was assessed. Silencing of only one previously uncharacterized MKP, designated AtMKP2, rendered the plants hypersensitive to oxidative stress. AtMKP2-suppressed plants displayed significantly prolonged MPK3 and MPK6 activation during ozone treatment, and recombinant AtMKP2 was able to dephosphorylate both phospho-MPK3 and phospho-MPK6 in vitro, providing direct evidence that AtMKP2 may target these oxidant-activated MAPKs. In addition, the in vitro phosphatase activity of AtMKP2 was enhanced by co-incubation with either recombinant MPK3 or MPK6. In AtMKP2:YFP-expressing plants, the fusion protein was localized predominantly in the nucleus, the same compartment into which ozone-activated MPK3 and MPK6 have previously been shown to be translocated. Taken together, these data suggest that AtMKP2, a novel MKP protein in Arabidopsis, acts upon MPK3 and -6, and serves as a positive regulator of the cellular response to oxidant challenge.

Biodiesel produced by the transesterification of vegetable oils (VOs) is a promising alternative fuel to diesel regarding the limited resources of fossil fuel and the environmental concerns. In this work, an environmentally benign process for the production of biodiesel from VOs using heterogeneous catalyst was developed. Na/NaOH/γ-Al2O3 heterogeneous base catalyst was firstly adopted for the production of biodiesel. A study for optimizing the reaction conditions such as the reaction time, the stirring speed, the use of co-solvent, the oil to methanol ratio, and the amount of catalyst, was performed. The Na/NaOH/γ-Al2O3 heterogeneous base catalyst showed almost the same activity under the optimized reaction conditions compared to conventional homogeneous NaOH catalyst. The basic strength of Na/NaOH/γ-Al2O3 catalyst was estimated and the correlation with the activity towards transesterification was proposed.

This paper proposes a design methodology for a soft sensor when the process has multiple operation modes due to frequent grade changes. The proposed soft sensor is constructed in two steps. At the first step, local models combined with a global model are applied since the global linear empirical model for multi-mode operation process results in the poor prediction power. At the second step, the relationship between MIcum and MIjns is used to compensate degradation of the prediction power for the regression model between the current process variables and MIcum instead of MIins. We greatly improved prediction power of soft sensor for multi-mode operation process. The industrial case study has shown the accuracy of the soft sensor.

A highly CO2-tolerant microalga, Chlorella sp., was isolated and its cultural characteristics were examined. Chlorella KR-1 showed excellent stabilities to high concentrations of CO2 and high temperature. It maintained good growth in air containing up to 30% CO2 and at temperatures up to 40°C. The alga showed a good growth rate in a broad range of pH. Chlorella KR-1 was found to be suitable for high density culture. The results indicated the possibility of using the KR-1 strain for mass cultivation using stack gases.