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By-products from the sugar industry (e.g., blackstrap molasses) can be a source of bioactive compounds (e.g., phenolics) known to have antimicrobial, antioxidant, anticancer, and anti-inflammatory properties. These bioactive molecules can be used in the green synthesis of metal nanoparticles. Metal nanoparticles have gathered attention because of their novel physico-chemical properties and potential biological applications (e.g., biocides, fungicides, pesticides, targeted drug and gene delivery, biosensing, medical implants, and plant biostimulants). Gold, silver, iron, and copper nanoparticles are of particular interest as they can be easy to operate and are cost effective, and biocompatible, and their biological activities can be enhanced by surface modifications. In this study, the reducing potential of the phenolic compounds in molasses was investigated for the synthesis of silver nanoparticles without the external addition of reducing agents. The reddish color formation and peak appearance at 420 nm were indications of the successful synthesis of the silver nanoparticles. The synthesized nanoparticles and reducing biomolecules were further characterized by microscopy (SEM, TEM, EDS) and spectroscopy (FTIR) techniques indicating nanoparticles of spherical shape and with particle sizes ranging from 15 nm–45 nm. Their antimicrobial activity was evaluated against several Gram-positive and Gram-negative bacteria. The synthesized nanoparticles showed a biocidal effect, further confirmed by microscopy techniques. It appears that the nanoparticles are interacting with the cell surface of bacteria, penetrating the cell and also causing the disruption of intracellular organelles.

Xylooligosaccharides (XOS) is a group of emerging prebiotics that selectively stimulate the growth of advantageous gastrointestinal bacteria benefitting the host’s gut health and functionality. XOS can achieve positive biological effects at low daily doses and low caloric content, properties that are the same or more desirable than the already established prebiotics. XOS are present in plants in very low amounts so there is a great opportunity to isolate XOS with varying degrees of polymerization from the hemicellulose (xylan) fraction of lignocellulosic materials (e.g., bagasse), a source that offers both economic and environmental advantages. In this study, the recovery of XOS by the combined use of activated carbon adsorption, water washing and ethanol desorption from diluted acid pretreated energy cane bagasse hydrolysates was evaluated. The recovered XOS was tested for its prebiotic activity on Bifidobacterium adolescentis ATCC 15703. The final product of extracted XOS from energy cane bagasse (XOS EC Bagasse crude sample) had a purity of 93%, which was comparable to the purities observed with two commercially available XOS prebiotics, CPA (89%) and CPB (93%). XOS EC Bagasse crude sample exhibited prebiotic properties by stimulating the growth of B. adolescentis ATCC 15703 and by producing lactic acid, which were comparable to those observed with the commercial prebiotics.

This paper describes an optimal method of evaluating the synchronous reactance of the d - and q -axes simultaneously with rotor angle measurement. First, interactions among the variables such as the synchronous reactance of the d - and q -axes, the field current and the rotor angle through magnetic saturation are theoretically reviewed with a standard machine model. Next, with the steady-state test data, optimal values of Xd and Xq are evaluated simultaneously using an optimization technique to minimize the sum of 2-norm errors between the calculated and measured values in the field current and the rotor angle. The proposed method has been verified against both the 282 MVA salient-pole and 612 MVA round-rotor generators. The optimal value of the Xq / Xd ratio was found to be much smaller than that of manufacturer's data, and mismatches between the measured and calculated values in both the rotor angle and field current were significantly reduced. This systematic method is so simple that field engineers would find it easy to use. Thus, the rotor angle measurement makes it possible to derive the optimal values of Xd and Xq simultaneously, and the use of high-precision speed pickup sensor from all the generators is essential for improving machine model accuracy.

Frequency drops and the high ambient temperature cause a decrease in airflow and an increase in the exhaust gas temperature of a gas turbine (GT). These two conditions significantly reduce the maximum continuous power output of GTs. Correct modeling of these conditions under heavily loaded conditions, such as in hot summer, is very important. Otherwise, the simulated maximum output of GT may be significantly higher than the real one and estimation of frequency responsive reserve and spinning reserve may be gravely erroneous. This paper describes the modeling and simulation of a heavy-duty GT operating under temperature control to study its impact on power system stability. For the practical simulation, a simple logic was added to the temperature reference parameter to represent the GT under the temperature control mode under steady-state conditions in the popular Rowen GT model, and the bumpless tracking logic was considered in the proportional-integral temperature controller. For three widely used GT models, GAST, GAST2A, and GGOV1, the effect of the temperature control loop on the transient stability is reviewed in a simple manner by applying the three-phase fault. Finally, the impact of GT under temperature control operation on frequency stability was analyzed using the proposed GT model with the determined model parameters of a practical GT system with 341 MVA during frequency drop against a six-machine, 23-bus system.

The proposed algorithm is based on the discrete Fourier transform (DFT) and a software-based synchronous sampling technique that is locked to the power system frequency using reconfigurable field-programmable gate arrays (FPGAs). The main purposes of this paper are to provide a new method of recording the high-resolution rotor angle of a synchronous machine and a practical method for deriving more accurate d-q- axis synchronous machine parameters. An FPGA is used in realizing the rotor-angle transducer and it simultaneously detects the frequency of the generator terminal voltage. The DFT algorithm is combined with an interpolation technique that downsamples the high-frequency sampled data using the measured power system frequency. This paper also describes a practical method for determining synchronous machine model parameters. The proposed algorithm for recording the generator dynamics was implemented in terms of Labview, Real-Time PCI eXtensions for Instrumentation (PXI) target, and the FPGA, and was applied to generator testing of a 1205-MVA thermal power unit. Its synchronous machine parameters were also derived using the recorded rotor angle.

Astragalin (kaempferol-3-O-β- d -glucopyranoside, Ast) is a kind of flavonoid known to have anti-oxidant, anti-HIV, anti-allergic, and anti-inflammatory effects. It has low solubility in water. In this study, novel astragalin galactosides (Ast-Gals) were synthesized using β-galactosidase from Bacillus circulans and reaction conditions were optimized to increase the conversion yield of astragallin. Purified Ast-Gal1 (11.6% of Ast used, w/w) and Ast-Gal2 (6.7% of Ast used, w/w) were obtained by medium pressure chromatography (MPLC) with silica C18 column and open column packed with Sephadex LH-20. The structures of Ast-Gal1 and Ast-Gal2 were identified by nuclear magnetic resonance (NMR) to be kaempferol-3-O-β- d -glucopyranosyl-(1 → 6)-β- d -galactopyranoside and kaempferol-3-O-β- d -glucopyranosyl-(1 → 6)-β- d -galactopyranosyl-(1 → 4)-β- d -galactopyranoside, respectively. The water solubility of Ast, Ast-Gal1, and Ast-Gal2 were 28.2 ± 1.2 mg/L, 38,300 ± 3.5 mg/L, and 38,800 ± 2.8 mg/L, respectively. The SC50 value (the concentration required to scavenge 50% of the ABTS + ) of Ast, Ast-Gal1, and Ast-Gal2 were 5.1 ± 1.6 μM, 6.5 ± 0.4 μM, and 4.9 ± 1.1 μM, respectively. The IC50 values (the half maximal inhibitory concentration) of Ast, Ast-Gal1, and Ast-Gal2 against angiotensin converting enzyme (ACE) were 171.0 ± 1.2 μM, 186.0 μM, and 139.0 ± 0.2 μM, respectively.

Epigallocatechin gallate (EGCG) is the most abundant catechin found in the leaves of green tea, Camellia sinensis. In this study, novel epigallocatechin gallate-glucocides (EGCG-Gs) were synthesized by using dextransucrase from Leuconostoc mesenteroides B-1299CB4. Response surface methodology was adopted to optimize the conversion of EGCG to EGCG-Gs, resulting in a 91.43% conversion rate of EGCG. Each EGCG-G was purified using a C18 column. Of nine EGCG-Gs identified by nuclear magnetic resonance analysis, five EGCG-Gs (2 and 4–7) were novel compounds with yields of 2.2–22.6%. The water solubility of the five novel compounds ranged from 229.7 to 1878.5 mM. The 5′-OH group of EGCG-Gs expressed higher antioxidant activities than the 4′-OH group of EGCG-Gs. Furthermore, glucosylation at 7-OH group of EGCG-Gs was found to be responsible for maintaining tyrosinase inhibitory activity and increasing browning-resistant activities.

95.3% of the sucrose in a feed batch fermentation (300 g/L) was hydrolyzed by Leuconostoc mesenteroides subp. mesenteroides NRRL B-23188 glucansucrase. Further, the glucose of sucrose formed glucooligosaccharides (GOS) of degree of polymerization (DP) over 2, together with 91.6% of the maltose (200 g/L). Lime saccharate (lime sucrate) was used to control the pH during fermentation. The GOS products had DP between 2 and 7. When Streptococcus mutans mutansucrase (0.1 U/mL) reacted with 0.1% sucrose, addition of 0.1 ~ 10% GOS to the mutansucrase reaction digest resulted in a 56 ~ 90% reduction of mutan formation. GOS also reduced E. coli (72.2%) and Salmonella sp. (over 40.0%) growth, when 2.5% GOS was used as a single carbon source, compared to growth using glucose. The calculated glycemic index and glycemic load of GOS was 8 and 1, respectively, based on a 10 g carbohydrate serving. GOS was calculated to have 2.43 kcal/g. After a glucose tolerance test was performed using C57BL/6 mice, we found that mice treated with GOS showed a 59.4% lower increase in plasma glucose than those treated with maltose.

Transglycosylation is one of enzymatic methods to improve the physical and biochemical properties of various functional compounds. In this study, stevioside glucosides were synthesized using sucrose as a substrate, stevioside (Ste) as an acceptor, and dextransucrase from Leuconostoc mesenteroides B-512 F/KM. The highest Ste conversion yield of 98% was obtained with 50 mg/mL Ste, 800 mM sucrose, and dextransucrase 4 U/mL at 28 °C for 6 h. The concentration of Ste was unchanged while of Ste-G1 was increased from 7.7 mM to 9.1 mM as the Ste acceptor reaction digest was treated with dextranase from Lipomyces starkeyi. Ste-G1 (13-O-β-sophorosyl-19-O-β-isomaltosyl-steviol), Ste-G2 (13-O-(β-(1→6) glucosyl)-β-glucosylsophorosyl-19-O-β-isomaltosyl-steviol), and Ste-G2′ (13-O-β-sophorosyl-19-O-β-isomaltotriosyl-steviol) were determined by NMR. These glucosylated Ste showed increased stabilities at pH 2, 60 °C for 48 h as compared to Ste. Ste-G1, Ste-G2, and Ste-G2′ inhibited the insoluble glucan synthesis from sucrose by mutansucrase from Streptococcus muntans by the transfer of the glucosyl group of sucrose to Ste-G1, Ste-G2, and Ste-G2′. The relative water solubility of curcumin, pterostilbene or idebenone was increased by Ste or Ste glucosides treatment. Ste and Ste-G1 restored cell viability in RAW264.7 cells at concentrations up to 8 mg/mL and inhibited nitric oxide production in LPS-induced RAW264.7 cells with IC50 of 3.29 and 1.87 mg/mL.

Summary Efficient ethanol production from lignocellulosic biomass requires highly degradable feedstock; therefore, there is a similarity between forage crop production for ruminant animals and ethanol production from lignocellulosic biomass. Feed value analysis techniques may be used to estimate lignocellulosic biomass quality. Because lignin and its derivatives in cell walls are major compounds interrupting biomass degradation, fiber analysis and in vitro incubation tests were conducted with switchgrass (Panicum virgatum) and energycane (Saccharum spp.) biomass collected at 100 and 120 g lignin (acid detergent lignin) kg−1 DM (dry matter). Mean NDF (neutral detergent fiber) in switchgrass was consistently greater than that of energy cane regardless of lignin levels, while ADF (acid detergent fiber) did not differ. Mean of energycane in vitro true digestibility and digestible neutral detergent fiber were greater than those of switchgrass. The ADF and ruminal fermentation rate averaged by lignin levels differed, while most of the analysis results did not. Based on ADF and NDF concentrations, switchgrass contained a greater concentration of hemicellulose than energycane, while cellulose concentration was similar. Fermentability of energycane was consistently greater than that of switchgrass. Fermentation gas volume was positively correlated with cellulosic biomass degradation for ethanol production. Consequently, fermentation gas kinetic parameters obtained from biomass fermentation with rumen fluid or with yeast indicate that the fermentable pool size is the parameter most closely correlated to ethanol production potential across the species. Results obtained from feed value analyses demonstrate fermentation variability and meaningful relationships between fermentation gas parameters and ethanol production. Thus, the ruminal fermentation process is useful as a screening tool for ethanol production potential of biofuel feedstock. Copyright © 2015 John Wiley & Sons, Ltd.

This paper proposes a new simplified model of a doubly fed induction generator (DFIG) that is integrated with a rotor-side converter for studies of large-scale transient stability. This model accurately considers the rotor field dynamics of an induction generator to yield simulation results that are more accurate in terms of voltage stability, as well as angle stability. The purpose of this paper is to provide a simple but effective DFIG model for the study of large-scale transient stability, and to examine the important aspects of rotor voltage and rotor slip power. This new simplified DFIG model with an electric/turbine control system was tested against a six-machine and 23-bus system, and the responses obtained in case studies of transient stability were compared with those of a PSS/E program. Finally, the proposed DFIG model was also validated by comparing the simulation results for a single-machine and infinite-bus system with those of PSCAD/EMTDC.

Sugarcane molasses was studied as a substrate for butanol and isopropanol fermentation by Clostridium beijerinckii optinoii in 10 L batch fermentations. Using 3% glucose as a carbon source, the solvent concentrations (butanol and isopropanol) and solvent yields were 10.03 g/L and 0.43 g/g, respectively, with a sugar utilization of 81.7%. However, on 2.5% glucose medium supplemented with an additional 0.5% sugar supplied as sugarcane molasses, sugar consumption was 100% and the solvent concentrations (13.37 g/L) and solvent yields (0.45 g/g) were both higher. Sugarcane molasses (3%) with or without invertase and without P2 vitamin/mineral solution produced a solvent concentration of 12.15 ~ 12.81 g/L and solvent yield of. 0.39 ~ 0.41 g/g with sugar consumption of 94.88 ~ 100%. This work demonstrated the value of sugarcane molasses as a supplementary nutrient for glucose fermentation for butanol and isopropanol production using C. beijerinckii optinoii as well as its value as a low cost carbon and media source.

Solubility is an important factor for achieving the desired plasma level of drug for pharmacological response. About 40% of drugs are not soluble in water in practice and therefore are slowly absorbed, which results in insufficient and uneven bioavailability and GI toxicity. Rubusoside (Ru) is a sweetener component in herbal tea and was discovered to enhance the solubility of a number of pharmaceutically and medicinally important compounds, including anticancer compounds. In this study, thirty-one hydrolyzing enzymes were screened for the conversion of stevioside (Ste) to Ru. Recombinant lactase from Thermus thermophiles which was expressed in Escherichia coli converted stevioside to rubusoside as a main product. Immobilized lactase was prepared and used for the production of rubusoside; twelve reaction cycles were repeated with 95.4% of Ste hydrolysis and 49 g L(-1) of Ru was produced. The optimum rubusoside synthesis yield was 86% at 200 g L(-1), 1200 U lactase. The purified 10% rubusoside solution showed increased water solubility of liquiritin from 0.98 mg mL(-1) to 4.70±0.12 mg mL(-1) and 0 mg mL(-1) to 3.42±0.11 mg mL(-1) in the case of teniposide.

Additional power generation sites have been limited in Korea, despite the fact load demands are gradually increasing. In order to meet these increasing demands, Korea’s power system company has begun constructing new generators at existing sites. Thus, multi-unit plants can create problems in terms of transient stability when a large disturbance occurs. This paper proposes a hybrid superconducting fault current limiter (SFCL) application to enhance the transient stability of multi-unit power plants. SFCLs reduce fault currents, and limitation currents decrease the imbalance of the mechanical and electrical torque of the generators, resulting in an improvement in transient stability.

Recent technological achievement in areas of distributed computing, networking, high speed communications and digital control, as well as the availability of accurate GPS time source, are rapidly becoming the enabling factors for the development of a new generation of real time power grid monitoring tools. KDN (Korea electric power Date Network Co.) R&D department with KERI, Korea University and LSIS has embarked on long term research and development work in the field of wide area systems specifically applied to the power transmission grid in Korea. Primary focus will be on wide area measurement and monitoring, analysis, assessment technique and tools aimed at preventing the propagation of power grid instabilities. Of special interest are voltage stability and small signal stability. This project aligns with KEPCO (the Korea Electric Power Company). In this paper, case studies performed with the use of the developed system are presented.

Xylose, the major constituent of xylans, as well as the side chain sugars, such as arabinose, can be metabolized by engineered yeasts into ethanol. Therefore, xylan-degrading enzymes that efficiently hydrolyze xylans will add value to cellulases used in hydrolysis of plant cell wall polysaccharides for conversion to biofuels. Heterogeneous xylan is a complex substrate, and it requires multiple enzymes to release its constituent sugars. However, the components of xylan-degrading enzymes are often individually characterized, leading to a dearth of research that analyzes synergistic actions of the components of xylan-degrading enzymes. In the present report, six genes predicted to encode components of the xylan-degrading enzymes of the thermophilic bacterium Caldicellulosiruptor bescii were expressed in Escherichia coli , and the recombinant proteins were investigated as individual enzymes and also as a xylan-degrading enzyme cocktail. Most of the component enzymes of the xylan-degrading enzyme mixture had similar optimal pH (5.5 to ∼6.5) and temperature (75 to ∼90°C), and this facilitated their investigation as an enzyme cocktail for deconstruction of xylans. The core enzymes (two endoxylanases and a β-xylosidase) exhibited high turnover numbers during catalysis, with the two endoxylanases yielding estimated k cat values of ∼8,000 and ∼4,500 s −1 , respectively, on soluble wheat arabinoxylan. Addition of side chain-cleaving enzymes to the core enzymes increased depolymerization of a more complex model substrate, oat spelt xylan. The C. bescii xylan-degrading enzyme mixture effectively hydrolyzes xylan at 65 to 80°C and can serve as a basal mixture for deconstruction of xylans in bioenergy feedstock at high temperatures.

The human fibroblast collagenase catalytic domain (MMP1ca) that is considered a prototype for all interstitial collagenase and plays an important role in the turnover of collagen fibrils in the matrix was expressed as an inclusion body in the Escherichia coli. The purified enzyme displayed activity with substrate Dnp-Pro-Leu-Ala-Leu-Trp-Ala-Arg-OH with a K(m) value of 26.61±1.42 μM. The inhibition activity of the nine flavonoid compounds and gallic acid against MMP1ca was examined. Among the compounds tested, the IC(50) of seven flavonoid compounds were determined and ranged from 14.13 to 339.21 μM. Epigallocatechin gallate (EGCG) showed the highest inhibition toward MMP1ca with IC(50) values of 14.13±0.49 μM. EGCG showed a competitive inhibition pattern with a K(i) value of 10.47±0.51 μM. The free binding energy of EGCG against MMP1ca was -13.07 kcal mol(-1), which was calculated by using Autodock 3.0.5 software and showed numerous hydrophobic and hydrogen bond interactions. The galloyl group of EGCG, gallocatechin gallate and epicatechin gallate was determined to be important for inhibitory activity against MMP1ca.

Ruminococcus albus 8 is a specialist plant cell wall degrading ruminal bacterium capable of utilizing hemicellulose and cellulose. Cellulose degradation requires a suite of enzymes including endoglucanases, exoglucanases and β-glucosidases. The enzymes employed by R. albus 8 in degrading cellulose are yet to be completely elucidated. Through bioinformatic analysis of a draft genome sequence of R. albus 8, seventeen putatively cellulolytic genes were identified. The genes were heterologously expressed in E. coli and purified to near homogeneity. On biochemical analysis with cellulosic substrates, seven of the gene products (Ra0185, Ra0259, Ra0325, Ra0903, Ra1831, Ra2461 and Ra2535) were identified as endoglucanases, releasing predominantly cellobiose and cellotriose. Each of the R. albus 8 endoglucanases, except for Ra0259 and Ra0325, bound to the model crystalline cellulose Avicel, confirming functional carbohydrate binding modules (CBMs). The polypeptides for Ra1831 and Ra2535 were found to contain distantly related homologs of CBM65. Mutational analysis of residues within the CBM65 of Ra1831 identified key residues required for binding. Phylogenetic analysis of the endoglucanases revealed three distinct subfamilies of glycoside hydrolase family 5 (GH5). Our results demonstrate that this fibrolytic bacterium uses diverse GH5 catalytic domains appended with different CBMs, including novel forms of CBM65, to degrade cellulose.

Human intestinal maltase (HMA) is an α-glucosidase responsible for the hydrolysis of α-1,4-linkages from the non-reducing end of malto-oligosaccharides. HMA has become an important target in the treatment of type-2 diabetes. In this study, epigallocatechin gallate (EGCG) and EGCG glucoside (EGCG-G1) were identified as inhibitors of HMA by an in vitro assay with IC50 of 20 ± 1.0 and 31.5 ± 1.0 μM, respectively. A Lineweaver-Burk plot confirmed that EGCG and EGCG-G1 were competitive inhibitors of maltose substrate against HMA and inhibition kinetic constants (K i ) calculated from a Dixon plot were 5.93 ± 0.26 and 7.88 ± 0.57 μM, respectively. Both EGCG and EGCG-G1 bound to the active site of HMA with numerous hydrophobic and hydrogen bond interactions.

Ruminococcus albus 8 is a ruminal bacterium capable of metabolizing hemicellulose and cellulose, the major components of the plant cell wall. The enzymes that allow this bacterium to capture energy from the two polysaccharides, therefore, have potential application in plant cell wall depolymerization, a process critical to biofuel production. For this purpose, a partial genome sequence of R. albus 8 was generated. The genomic data depicted a bacterium endowed with multiple forms of plant cell wall-degrading enzymes. The endoxylanases of R. albus 8 exhibited diverse modular architectures, including incorporation of a catalytic module, a carbohydrate binding module, and a carbohydrate esterase module in a single polypeptide. The accessory enzymes of xylan degradation were a β-xylosidase, an α- l -arabinofuranosidase, and an α-glucuronidase. We hypothesized that due to the chemical complexity of the hemicellulose encountered in the rumen, the bacterium uses multiple endoxylanases, with subtle differences in substrate specificities, to attack the substrate, while the accessory enzymes hydrolyze the products to simple sugars for metabolism. To test this hypothesis, the genes encoding the predicted endoxylanases were expressed, and the proteins were biochemically characterized either alone or in combination with accessory enzymes. The different endoxylanase families exhibited different patterns of product release, with the family 11 endoxylanases releasing more products in synergy with the accessory enzymes from the more complex substrates. Aside from the insights into hemicellulose degradation by R. albus 8, this report should enhance our knowledge on designing effective enzyme cocktails for release of fermentable sugars in the biofuel industry.

The dynamic response of a multi-MW wind turbine to a sudden change in wind speed is usually slow, because of the slow pitch control system. This could cause a large excursion of the rotor speed and an output power over the rated. A feedforward pitch control can be applied to minimize the fluctuations of these parameters. This paper introduces the complete design steps for a feedforward pitch controller, which consist of three stages, i.e. the aerodynamic torque estimation, the 3-dimensional lookup table for the wind seed estimation, and the calculation of the feedforward pitch amount. The effectiveness of the feedforward control is verified through numerical simulations of a multi-MW wind turbine.

(−)-Epigallocatechin-3-gallate (EGCG) has been reported to inhibit cellular proliferation and induce apoptosis in a range of cancer cells. This study examined the cytotoxicity of EGCG glucoside on human laryngeal epidermoid carcinoma Hep2 cells. The EGCG glucoside treatment decreased the cell viability in Hep2 cells. Furthermore, EGCG glucoside caused apoptotic morphological changes with chromatin condensation and nuclear fragmentation, as observed by a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and activated caspase-3 immunohistochemisty. However, the EGCG glucoside did not induce the production of reactive oxygen species (ROS), suggesting that oxidative stress is not involved in the apoptotic response. EGCG glucoside induces apoptosis in Hep2 cells through not the generation of ROS, but the activation of caspase-3.

Enzymatic depolymerization of lignocellulose by microbes in the bovine rumen and the human colon is critical to gut health and function within the host. Prevotella bryantii B(1)4 is a rumen bacterium that efficiently degrades soluble xylan. To identify the genes harnessed by this bacterium to degrade xylan, the transcriptomes of P. bryantii cultured on either wheat arabinoxylan or a mixture of its monosaccharide components were compared by DNA microarray and RNA sequencing approaches. The most highly induced genes formed a cluster that contained putative outer membrane proteins analogous to the starch utilization system identified in the prominent human gut symbiont Bacteroides thetaiotaomicron. The arrangement of genes in the cluster was highly conserved in other xylanolytic Bacteroidetes, suggesting that the mechanism employed by xylan utilizers in this phylum is conserved. A number of genes encoding proteins with unassigned function were also induced on wheat arabinoxylan. Among these proteins, a hypothetical protein with low similarity to glycoside hydrolases was shown to possess endoxylanase activity and subsequently assigned to glycoside hydrolase family 5. The enzyme was designated PbXyn5A. Two of the most similar proteins to PbXyn5A were hypothetical proteins from human colonic Bacteroides spp., and when expressed each protein exhibited endoxylanase activity. By using site-directed mutagenesis, we identified two amino acid residues that likely serve as the catalytic acid/base and nucleophile as in other GH5 proteins. This study therefore provides insights into capture of energy by xylanolytic Bacteroidetes and the application of their enzymes as a resource in the biofuel industry.

Through the development of phasor measurement units (PMU), various aspects of power system dynamic behavior could be monitored and diagnosed. Monitoring dynamic voltage stability has become one of the achievements we can obtain from PMUs. It is very important to select the most appropriate method for the Korea Electric Power Corporation (KEPCO) system since there are many voltage stability indices. In this paper, we propose an advanced WAVI (Wide Area Voltage Stability) that is well suited for the purposes of monitoring the dynamic voltage stability of KEPCO’s PMU installation plan. The salient features of the proposed index are: i) it uses only PMU measurements without coupling with EMS data; ii) it is computationally unburdened and can be applied to real-time situations. The proposed index is applied to the KEPCO test system and the results show that it successfully predicts voltage instability through comparative studies.

Acarbose-fructoside (acarbose-Fru) was newly synthesized via the acceptor reaction of a levansucrase from Leuconostoc mesenteroides B-512 FMC with acarbose and sucrose. The resultant product was separated with 10.5% purification yield via Bio-gel P-2 column chromatography and HPLC. Its structure was determined to be 1 I -β- d -fructofuranosyl α-acarbose, according to the results of 1 H, 13 C, HSQC, and HMBC analyses. Acarbose-Fru was inhibited competitively on α-glucosidase ( A. niger and baker's yeast) but mixed noncompetitively on α-amylases ( A. oryzae and porcine pancreatic). Compared to acarbose, acarbose-Fru exhibited inhibition potency of 1.12 or 1.52 on A. niger α-glucosidase or A. oryzae α-amylase, respectively. Additionally, acarbose-Fru was identified as a novel substrate for dextransucrase with K m and V max values of 189.0 mM and 8.51 μmol/(mg min), respectively. Therefore, acarbose-Fru as a substrate might be synthesized novel acarbose derivatives by using dextransucrase.

Bacteria and fungi are thought to degrade cellulose through the activity of either a complexed or a noncomplexed cellulolytic system composed of endoglucanases and cellobiohydrolases. The marine bacterium Saccharophagus degradans 2-40 produces a multicomponent cellulolytic system that is unusual in its abundance of GH5-containing endoglucanases. Secreted enzymes of this bacterium release high levels of cellobiose from cellulosic materials. Through cloning and purification, the predicted biochemical activities of the one annotated cellobiohydrolase Cel6A and the GH5-containing endoglucanases were evaluated. Cel6A was shown to be a classic endoglucanase, but Cel5H showed significantly higher activity on several types of cellulose, was the highest expressed, and processively released cellobiose from cellulosic substrates. Cel5G, Cel5H, and Cel5J were found to be members of a separate phylogenetic clade and were all shown to be processive. The processive endoglucanases are functionally equivalent to the endoglucanases and cellobiohydrolases required for other cellulolytic systems, thus providing a cellobiohydrolase-independent mechanism for this bacterium to convert cellulose to glucose.

SCADA is the acronym of Supervisory Control and Data Acquisition which means the communication scheme for telemetry measurement and control of the automated control system. SCADA system was introduced for the monitor and control of manufacturing process on local basis in the beginning. As the information technology has been advanced SCADA system has also evolved into larger and more automated system covering wide area. Today SCADA system has been introduced into the critical infrastructures as well as modern industrial facilities. Electric Power system is a representative system using SCADA network. Electricity is not able to be stored in large quantity especially considering economic efficiency therefore it is critical to be balanced between supply and demand, which is the main function of SCADA system. This paper introduces the structure and characteristics of SCADA system and communication, and the security devices which it has been studied for securing SCADA communication.

This paper describes the new eigenvalue algorithm exploiting the Implicit Restarted Arnoldi Method (IRAM) and its application to power systems. IRAM is a technique for combining the implicitly shifted mechanism with a k-step Arnoldi factorization to obtain a truncated form of the implicitly shifted QR iteration. The numerical difficulties and storage problems normally associated with the Arnoldi process are avoided. Two power systems, one of which has 36 state variables and the other 150 state variables, have been tested using the ARPACK program, which uses IRAM, and the eigenvalue results are compared with the results obtained from the conventional QR method.

The gene encoding sucrose phosphorylase (742sp) in Leuconostoc mesenteroides NRRL B-742 was cloned and expressed in Escherichia coli. The nucleotide sequence of the transformed 742sp comprised an ORF of 1,458 bp giving a protein with calculated molecular mass of 55.3 kDa. 742SPase contains a C-terminal amino acid sequence that is significantly different from those of other Leu. mesenteroides SPases. The purified 742SPase had a specific activity of 1.8 U/mg with a K (m) of 3 mM with sucrose as a substrate; optimum activity was at 37 degrees C and pH 6.7. The purified 742SPase transferred the glucosyl moiety of sucrose to cytosine monophosphate (CMP).

This paper presents a practical approach for supplementary control of high voltage direct current (HVDC) system to damp subsynchronous oscillation (SSO) involving HVDC converters and turbine-generator shaft systems. A novel eigenvalue analysis (NEA) program, HVDC system modeling to consider steady-state and dynamic conditions in a combined ac/dc system, and an appropriate control scheme have been utilized. The design method proposed facilitates the design of a subsynchronous oscillation damping controller (SODC) to provide positive damping torque for the dominant torsional mode in combined ac/dc systems. The suggested SODC design method has been applied to an ac/dc system to verify its practicality using the EMTDC simulation program.

Two arbutin glucosides were synthesized via the acceptor reaction of a glucansucrase from Leuconostoc mesenteroides B-1299CB with arbutin and sucrose. The glucosides were purified by Bio-gel P-2 column chromatography and high-performance liquid chromatography, and the structures were elucidated as 4-hydroxyphenyl beta-isomaltoside (arbutin-G1), 4-hydroxyphenyl beta-isomaltotrioside (arbutin-G2), according to the results of (1)H, (13)C, heteronuclear single-quantum coherence, (1)H-(1)H COSY, and heteronuclear multiple-bond correlation analyses. Arbutin glucoside (4-hydroxyphenyl beta-isomaltoside) exhibited slower effects on 1,1-diphenyl-2-picrylhydrazyl radical scavenging and similar effects on tyrosinase inhibition, and increased inhibitory effect on matrix metalloproteinase-1 production induced by UVB than arbutin.

In this study, two quercetin-α- d -glucopyranosides were synthesized via the acceptor reaction of a glucansucrase obtained from Leuconostoc mesenteroides B-1299CB, with quercetin and sucrose. The two transfer products were purified via HPLC, and the structures of the products were identified as quercetin-4′-O-α- d -glucopyranoside (Q-G1) and quercetin-3′-O-α- d -glucopyranoside (Q-G1′), in accordance with the results of 1H, 13C, HSQC, H-H COSY, HMBC analyses. The primary product (Q-G1) evidenced slower effects on DPPH radical-scavenging activity (SC50 = 25.2 μM) than was seen with quercetin (SC50 = 6.5 μM). The water solubility of Q-G1 was 12.7 mM, whereas the quercetin was barely soluble in water. The Ki value of Q-G1 (674.5 μM) was almost identical to that of quercetin (673.3 μM) with regard to tyrosinase inhibition effects.

Clostridium beijerinckii optinoii is a Clostridium species that produces butanol, isopropanol and small amounts of ethanol. This study compared the performances of batch and continuous immobilized cell fermentations, investigating how media flow rates and nutritional modification affected solvent yields and productivity. In 96-h batch cultures, with 80 % of the 30 g L(-1) glucose consumed in synthetic media, solvent concentration was 9.45 g L(-1) with 66.0 % as butanol. In a continuous fermentation using immobilized C. beijerinckii optinoii cells, also with 80 % of 30 g L(-1) glucose utilization, solvent productivity increased to 1.03 g L(-1) h(-1). Solvent concentration reached 12.14 g L(-1) with 63.0 % as butanol. Adjusting the dilution rate from 0.085 to 0.050 h(-1) to allow extended residence time in column was required when glucose concentration in fresh media was increased from 30 to 50 g L(-1). When acetate was used to improve the buffer capacity in media, the solvent concentration reached 12.70 on 50 g L(-1) glucose. This continuous fermentation using immobilized cells showed technical feasibility for solvent production.

Leuconostoc mesenteroides NRRL B-1149 sucrose phosphorylase (SPase) gene, 1149sp, was isolated and characterized. It is composed of 1479 bp nucleotides and encodes a 1149SPase of 492 amino acid residues with a calculated molecular mass of 56.1 kDa. It has unique C-terminal amino acid sequence (439DVETPSDTTIKITRKDKSGENVAVLVANAADKTFTITANGEEILANTEADKQQL492). 1149sp was expressed in Escherichia coli and the purified 1149SPase specific activity was 1.49 U/mg for sucrose. The optimum temperature and pH for SPase activities were ranged broad between 20 and 50 °C, between pH 6.0 and 7.5, respectively. The optimum temperature and pH were 37 °C at pH 6.7 and it showed Km of 6.3 mM and kcat of 1.59 s−1 for sucrose. It had a broad range of acceptor specificity and transferred the glucosyl moiety of sucrose or glucose-1-phosphate to various acceptors.

Three epigallocatechin gallate (EGCG) glucosides were synthesized by the acceptor reaction of a glucansucrase from Leuconostoc mesenteroides B-1299CB with EGCG and sucrose. After 1H, 13C, heteronuclear single quantum coherence, 1H–1H correlation spectroscopy, and heteronuclear multiple bond correlation nuclear magnetic resonance analyses, the glucosides were identified as (−)-epigallocatechin gallate 4′′-O-α- d -glucopyranoside (EGCG-G1), (−)-epigallocatechin gallate 7,4′′-di-O-α- d -glucopyranoside (EGCG-G2A), and (−)-epigallocatechin gallate 4′,4′′-di-O-α- d -glucopyranoside (EGCG-G2B). Two of the compounds (EGCG-G1 and EGCG-G2A) are reported for the first time. The EGCG glucosides exhibited antioxidant effects, depending on their structures (EGCG > EGCG-G1 > EGCG-G2A > EGCG-G2B). They also uniformly exhibited greater browning resistance than was observed in EGCG. Also, the water solubility of EGCG-G1, EGCG-G2A, and EGCG-G2B were 69, 126, and 122 times higher, respectively, than that of EGCG.

In this study, three epigallocatechin gallate glycosides were synthesized by the acceptor reaction of a glucansucrase produced by Leuconostoc mesenteroides B-1299CB with epigallocatechin gallate (EGCG) and sucrose. Each of these glycosides was then purified, and the structures were assigned as follows: epigallocatechin gallate 7-O-α-d-glucopyranoside (EGCG-G1); epigallocatechin gallate 4‘-O-α-d-glucopyranoside (EGCG-G1‘); and epigallocatechin gallate 7,4‘-O-α-d-glucopyranoside (EGCG-G2). One of these compounds (EGCG-G1) was a novel compound. The EGCG glycosides exhibited similar or slower antioxidant effects, depending on their structures (EGCG ≥ EGCG-G1 > EGCG-G1‘ > EGCG-G2), and also manifested a higher degree of browning resistance than was previously noted in EGCG. Also, EGCG-G1, EGCG-G1‘, and EGCG-G2 were 49, 55, and 114 times as water soluble, respectively, as EGCG. Keywords: Leuconostoc mesenteroides glucansucrase; EGCG; glycoside; acceptor reaction

This paper describes an eigenvalue analysis program with a novel approach for constructing the state matrix equations from the linearized multimachine power systems including the electrical transmission network dynamics about its operating point. The salient feather of formulation is that it allows for modular construction of various component models without rearrangement of the overall state space formulation. The paper also presents examples of its applications to the analysis of the IEEE benchmark models for subsynchronous resonance study.

Power system deregulation has become a worldwide trend which introduces competition in electric power system in order to realize efficient electricity production and investment. In this regards, it is very important to develop an electricity market simulator so that it is to analyze competitive market and train market operators and market participants. In this paper, we introduce some functional modules and a structure of Market simulator, also design the framework of market simulator composed of various and functional modules and based on the Korean market rules.

In this paper, we have proposed bifurcation control of voltage collapse in the model power system. Bifurcation theory is applied to analyze the voltage collapse in a model power system. Controls using existing power system facilities have suggested to mitigate voltage collapse phenomena. Nonlinear control law is designed to stabilize periodic solutions which emerges after voltage collapse phenomena. Moreover, a control law, which achieves reducing amplitude of the bifurcated periodic solution, is designed

We have previously demonstrated the production of glucooligosaccharides via a fermentation of sucrose with Leuconostoc mesenteroides NRRL B-742 using sodium hydroxide (NaOH) to control the pH. Because NaOH is expensive, we sought to minimize the cost of our process by substituting hydrated lime and saccharate of lime (lime sucrate) in its place. The yield of glucooligosaccharides using either 5 % lime (41.4 ± 0.5 g/100 g) or 5 % lime sucrate (40.0 ± 1.4 g/100 g) were both similar to the NaOH control (42.4 ± 1.5 g/100 g). Based on this, it appears that the cost associated with pH control in our process can be reduced by a factor of approximately 2.4 using lime instead of NaOH. Because our chromatographic stage is based on a Ca2+-form resin to separate glucooligosaccharides, the use of lime not only negates the need for costly de-salting via ion-exchange (elimination of two ion-exchange sections) prior to separation, but also greatly reduces the resin regeneration cost.

A systematic research is carried out on intermetallic NdNi5 for the hydrodesulfurization (HDS) of thiophene. The effect of calcination and presulfidation of intermetallic NdNi5 on thiophene HDS was examined and property changes of the catalyst during calcination, presulfidation, and reaction were observed by XRD, SEM, and surface area techniques. The intermetallic compound of NdNi5 is disintegrated to fine powder and recrystallized to Nd/Ni oxide and sulfide by calcination, presulfidation, and reaction. A model for the surface area increase of the catalyst during calcination, presulfidation, and reaction was proposed and the role of neodymium was explained.

This paper develops an analytical method for assessing the safety margins of a generation rejection scheme (GRS) reliably. It also presents a practical framework for implementing the proposed method integrated with energy management system and synchrophasor data in power grid operations. By employing a concept of virtual load connected to the critical generation bus of the single machine equivalent of the real-time operations case, we calculate, similar to transfer analysis, the allowable power to the virtual load in MW after tripping the pre-planned number of generation units and thus determine the required rejected power for the GRS initiating scenario. This virtual loading can be interpreted as the safety margin of the designed GRS to ensure its stabilizing operation. This research further develops a computationally efficient technique for refining the safety margin potentially with the measured synchrophasor data to improve the robustness of the GRS in practice. Understanding the safety margin is envisioned to help investigate and identify other practical options than tripping generators for protecting the system integrity. Accuracy and efficacy are demonstrated for real Korea power system cases.

A large polypeptide encoded in the genome of the thermophilic bacterium Caldicellulosiruptor bescii was determined to consist of two glycoside hydrolase (GH) modules separated by two carbohydrate-binding modules (CBMs). Based on the detection of mannanase and endoglucanase activities in the N-terminal GH5 and the C-terminal GH44 module, respectively, the protein was designated CbMan5B/Cel44A. A GH5 module with >99% identity from the same organism was characterized previously (X. Su, R. I. Mackie, and I. K. Cann, Appl. Environ. Microbiol. 78: 2230-2240, 2012); therefore, attention was focused on CbMan5A/Cel44A-TM2 (or TM2), which harbors the GH44 module and the two CBMs. On cellulosic substrates, TM2 had an optimal temperature and pH of 85�C and 5.0, respectively. Although the amino acid sequence of the GH44 module of TM2 was similar to those of other GH44 modules that hydrolyzed cello-oligosaccharides, cellulose, lichenan, and xyloglucan, it was unique that TM2 also displayed modest activity on mannose-configured substrates and xylan. The TM2 protein also degraded Avicel with higher specific activity than activities reported for its homologs. The GH44 catalytic module is composed of a TIM-like domain and a β-sandwich domain, which consists of one β-sheet at the N terminus and nine β-sheets at the C terminus. Deletion of one or more β-sheets from the β-sandwich domain resulted in insoluble proteins, suggesting that the β-sandwich domain is essential for proper folding of the polypeptide. Combining TM2 with three other endoglucanases from C. bescii led to modest synergistic activities during degradation of cellulose, and based on our results, we propose a model for cellulose hydrolysis and utilization by C. bescii .

Novel ampelopsin glucosides (AMPLS-Gs) were enzymatically synthesized and purified using a Sephadex LH-20 column. Each structure of the purified AMPLS-Gs was determined by nuclear magnetic resonance, and the ionic product of AMPLS-G1 was observed at m/z 505 (C₂₁H₂₂O₁₃·Na)⁺ using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. AMPLS-G1 was identified as ampelopsin-4'-O-α-D-glucopyranoside. The optimum condition for AMPLS-G1, determined using response surface methodology, was 70 mM ampelopsin, 150 mM sucrose, and 1 U/mL dextransucrase, which resulted in an AMPLS-G1 yield of 34 g/L. The purified AMPLS-G1 displayed 89-fold increased water solubility and 14.5-fold browning resistance compared to those of AMPLS and competitive inhibition against tyrosinase with a K(i) value of 40.16 μM. This value was smaller than that of AMPLS (K(i)=62.56 μM) and much smaller than that of β-arbutin (K(i)=514.84 μM), a commercial active ingredient of whitening cosmetics. These results indicate the potential of AMPLS and AMPLS-G1 as superior ingredients for functional cosmetics.

The hydrodesulfurization of thiophene was studied over unsupported nickel-neodymium bimetallic catalysts. The physical and chemical changes of bimetals were observed after calcination and presulfidation, respectively. The activity was increased with addition of neodymium to nickel catalysts and was in good correlation with the surface area of catalysts. Qualitative evidence from XRD and SEM on the role of Nd as a structural promoter were provided.

Saccharophagus degradans 2-40 is a marine gamma proteobacterium that can produce polyhydroxyalkanoates from lignocellulosic biomass using a complex cellulolytic system. This bacterium has been annotated to express three surface-associated β-glucosidases (Bgl3C, Ced3A, and Ced3B), two cytoplasmic β-glucosidases (Bgl1A and Bgl1B), and unusual for an aerobic bacterium, two cytoplasmic cellobiose/cellodextrin phosphorylases (Cep94A and Cep94B). Expression of the genes for each of the above enzymes was induced when cells were transferred into a medium containing Avicel as the major carbon source except for Bgl1B. Both hydrolytic and phosphorolytic degradation of cellobiose by crude cell lysates obtained from cellulose-grown cells were demonstrated and all of these activities were cell-associated. With the exception of Cep94B, each purified enzyme exhibited their annotated activity upon cloning and expression in E. coli. The five β-glucosidases hydrolyzed a variety of glucose derivatives containing β-1, (2, 4, or 6) linkages but did not act on any α-linked glucose derivatives. All but one β-glucosidases exhibited transglycosylation activity consistent with the formation of an enzyme-substrate intermediate. The biochemistry and expression of these cellobiases indicate that external hydrolysis by surface-associated β-glucosidases coupled with internal hydrolysis and phosphorolysis are all involved in the metabolism of cellobiose by this bacterium.

Hemicellulose and cellulose constitute two major targets in plants for cellulosic ethanol production. Whereas cellulose is a highly homogenous polymer of glucose joined in beta-1,4-glycosidic linkages, hemicellulose is mostly a heterogenous polymer of xylose and arabinose. Thus, the common arrangement of sugars in hemicelluloses, such as xylans from bioenergy feedstocks, is a beta-1,4-linked xylose backbone with side chains of arabinofuranosyl, acetyl, and 4-O-methyl glucuronyl groups. Complete hydrolysis of hemicellulose, therefore, requires a complex set of enzymes. Nature has selected for microorganisms that derive their carbon and energy sources from hemicellulose by an enzymatic action that deconstructs the polymer into its component sugars. Such microorganisms include the genus Prevotella. We are, therefore, using genomics, bioinformatics, biochemical, and structural analyses to unravel the strategies used by Prevotella spp to break down hemicellulose. Our ultimate goal is to rationally assemble enzyme cocktails from these microorganisms for use in the bioenergy industry. We have demonstrated that Prevotella bryantii grows rapidly on hemicellulose. Furthermore, the sequencing of its genome has allowed identification of genes likely to encode products for deconstruction of hemicellulosic substrates. Several of these genes have been expressed as recombinant proteins in E. coli. Experiments that aimed at examining the synergistic activities of the P. bryantii enzymes have led us to reconstitute an enzyme complex that degrades wheat arabinoxylan into its component sugars. This enzyme mixture is a promising product in our effort to deconstruct hemicellulose. We are currently using transcriptomic analyses to improve the enzyme cocktail, and structural analysis is also being applied to rationally synthesize new carbohydrate active enzymes with enhanced activities.