Electrochemically Synthesized Sb/Sb2O3 Composites as High-Capacity Anode Materials Utilizing a Reversible Conversion Reaction for Na-Ion Batteries.

Sb/Sb2O3 composites are synthesized by a one-step electrodeposition process from an aqueous electrolytic bath containing a potassium antimony tartrate complex. The synthesis process involves the electrodeposition of Sb simultaneously with the chemical deposition of Sb2O3, which allows for the direct deposition of morula-like Sb/Sb2O3 particles on the current collector without using a binder. Structural characterization confirms that the Sb/Sb2O3 composites are composed of approximately 90 mol % metallic Sb and 10 mol % crystalline Sb2O3. The composite exhibits a high reversible capacity (670 mAh g(-1)) that is higher than the theoretical capacity of Sb (660 mAh g(-1)). The high reversible capacity results from the conversion reaction between Na2O and Sb2O3 that occurs additionally to the alloying/dealloying reaction of Sb with Na. Moreover, the Sb/Sb2O3 composite shows excellent cycle performance with 91.8% capacity retention over 100 cycles, and a superior rate capability of 212 mAh g(-1) at a high current density of 3300 mA g(-1). The outstanding cycle performance is attributed to an amorphous Na2O phase generated by the conversion reaction, which inhibits agglomeration of Sb particles and acts as an effective buffer against volume change of Sb during cycling.

Efficient ethanol production from dried oil palm trunk treated by hydrothermolysis and subsequent enzymatic hydrolysis.

BACKGROUND: Oil palm trunk (OPT) is a valuable bioresource for the biorefinery industry producing biofuels and biochemicals. It has the distinct feature of containing a large amount of starch, which, unlike cellulose, can be easily solubilized by water when heated and hydrolyzed to glucose by amylolytic enzymes without pretreatment for breaking down the biomass recalcitrance. Therefore, it is suggested as beneficial to extract most of the starch from OPT through autoclaving and subsequent amylolytic hydrolysis prior to pretreatment. However, this treatment requires high capital and operational costs, and there could be a high probability of microbial contamination during starch processing. In terms of biochemical conversion of OPT, this study aimed to develop a simple and efficient ethanol conversion process without any chemical use such as acids and bases or detoxification. RESULTS: For comparison with the proposed efficient ethanol conversion process, OPT was subjected to hydrothermal treatment at 180 °C for 30 min. After enzymatic hydrolysis of PWS, 43.5 g of glucose per 100 g dry biomass was obtained, which corresponds to 81.3 % of the theoretical glucose yield. Through subsequent alcohol fermentation, 81.4 % ethanol yield of the theoretical ethanol yield was achieved. To conduct the proposed new process, starch in OPT was converted to ethanol through enzymatic hydrolysis and subsequent fermentation prior to hydrothermal treatment, and the resulting slurry was subjected to identical processes that were applied to control. Consequently, a high-glucose yield of 96.3 % was achieved, and the resulting ethanol yield was 93.5 %. CONCLUSIONS: The proposed new process was a simple method for minimizing the loss of starch during biochemical conversion and maximizing ethanol production as well as fermentable sugars from OPT. In addition, this methodology offers the advantage of reducing operational and capital costs due to minimizing the process for ethanol production by excluding expensive processes related to detoxification prior to enzymatic hydrolysis and fermentation such as washing/conditioning and solid-liquid separation of pretreated slurry. The potential future use of xylose-digestible microorganisms could further increase the ethanol yield from the proposed process, thereby increasing its effectiveness for the conversion of OPT into biofuels and biochemicals.

High-Performance Sb/Sb2 O3 Anode Materials Using a Polypyrrole Nanowire Network for Na-Ion Batteries.

Three-dimensional porous Sb/Sb2 O3 anode materials are successfully fabricated using a simple electrodeposition method with a polypyrrole nanowire network. The Sb/Sb2 O3 -PPy electrode exhibits excellent cycle performance and outstanding rate capabilities; the charge capacity is sustained at 512.01 mAh g(-1) over 100 cycles, and 56.7% of the charge capacity at a current density of 66 mA g(-1) is retained at 3300 mA g(-1) . The improved electrochemical performance of the Sb/Sb2 O3 -PPy electrode is attributed not only to the use of a highly porous polypyrrole nanowire network as a substrate but also to the buffer effects of the Sb2 O3 matrix on the volume expansion of Sb. Ex situ scanning electron microscopy observation confirms that the Sb/Sb2 O3 -PPy electrode sustains a strong bond between the nanodeposits and polypyrrole nanowires even after 100 cycles, which maintains good electrical contact of Sb/Sb2 O3 with the current collector without loss of the active materials.

Development of rice bran treatment process and its use for the synthesis of polyhydroxyalkanoates from rice bran hydrolysate solution.

Rice bran treatment process for the production of 43.7 kg of hydrolysate solution containing 24.41 g/L of glucose and small amount of fructose from 5 kg of rice bran was developed and employed to produce polyhydroxyalkanoates in recombinant Escherichia coli and Ralstonia eutropha strains. Recombinant E. coli XL1-Blue expressing R. eutropha phaCAB genes and R. eutropha NCIMB11599 could produce poly(3-hydroxybutyrate) with the polymer contents of 90.1 wt% and 97.2 wt%, respectively, when they were cultured in chemically defined MR medium and chemically defined nitrogen free MR medium containing 10 mL/L of rice bran hydrolysate solution, respectively. Also, recombinant E. coli XL1-Blue and recombinant R. eutropha 437-540, both of which express the Pseudomonas sp. phaC1437 gene and the Clostridium propionicum pct540 gene could produce poly(3-hydroxybutyrate-co-lactate) from rice bran hydrolysate solution. These results suggest that rice bran may be a good renewable resource for the production of biomass-based polymers by recombinant microorganisms.

Template-free electrochemical synthesis of Sn nanofibers as high-performance anode materials for Na-ion batteries.

Sn nanofibers with a high aspect ratio are successfully synthesized using a simple electrodeposition process from an aqueous solution without the use of templates. The synthetic approach involves the rapid electrochemical deposition of Sn accompanied by the strong adsorption of Triton X-100, which can function as a growth modifier for the Sn crystallites. Triton X-100 is adsorbed on the {200} crystallographic planes of Sn in an elongated configuration and suppressed the preferential growth of Sn along the [100] direction. Consequently, the Sn electrodeposits are forced to grow anisotropically in a direction normal to the (112) or (1̅12) plane, forming one-dimensional nanofibers. As electrode materials for the Na-ion batteries, the Sn nanofibers exhibit a high reversible capacity and an excellent cycle performance; the charge capacity is maintained at 776.26 mAh g(-1) after 100 cycles, which corresponds to a retention of 95.09% of the initial charge capacity. The superior electrochemical performance of the Sn nanofibers is mainly attributed to the high mechanical stability of the nanofibers, which originate from highly anisotropic expansion during sodiation and the pore volumes existing between the nanofibers.

Sugar yields from sunflower stalks treated by hydrothermolysis and subsequent enzymatic hydrolysis.

To produce fermentable sugar with fewer microbial inhibitors via few processes, batch-type hydrothermal treatments of sunflower stalks were performed, followed by enzymatic hydrolysis of pretreatment slurries with Cellic CTec2 and Cellic HTec2 (9:1, v/v, 0.1 ml/g dry biomass, 8.1FPU). The yields of hemicellulosic sugars were maximized at the pretreatment condition of 180°C for 30 min, while the furfural and 5-hydroxymethyl-2-furaldehyde (HMF) concentrations remained low. The glucose yield, however, was only 67.0% of the theoretical glucose yield (TGY). Either the treatment of raw biomass prior to pretreatment or the post-treatment of pretreated residue prior to enzymatic hydrolysis increased the glucose yield as follows: washing the pretreated solid with solvents (90% TGY)>partial removal of liquid fraction from the pretreatment slurry (PS, 83%)>removal of hot-water extractives from the biomass prior to pretreatment (77%)>prewetting of the biomass (70%).

In vitro BACE-1 inhibitory activity of resveratrol oligomers from the seed extract of Paeonia lactiflora.

A new resveratrol oligomer (1) together with eight related components (2- 9) were isolated from the seed extract of Paeonia lactiflora (Paeoniaceae) as active principles responsible for the inhibition of beta-site APP-cleaving enzyme 1 (BACE-1) in vitro. The chemical structure of 1 was established as (-)-7a,8a- CIS- ε-viniferin with the aid of spectroscopic analyses including NOESY experiments. All isolated resveratrol oligomers (1- 9) demonstrated significant inhibition on baculovirus-expressed BACE-1 in a dose-dependent manner, which was assessed by the FRET assay using Rh-EVNLDAEFK as a substrate in vitro.

HPLC-ELSD analysis of 18 platycosides from balloon flower roots (Platycodi Radix) sourced from various regions in Korea and geographical clustering of the cultivation areas.

An effective HPLC method to analyse platycosides from the balloon flower root was developed using ELSD. The optimum resolution of the platycosides was achieved on an ODS column with gradient elution of eluent A, 30mM ammonium acetate buffer (pH 4.81): methanol: acetonitrile=75:5:20 (v/v/v), and B, 69:5:26 (v/v/v). Amongst 18 platycosides, platycoside E showed the highest content, followed by polygalacin D2 and 3″-O-acetylplatyconic acid A. The sum of these three compounds was recommended for quality control of balloon flower root for medicinal purposes. The samples could be clustered into groups based on platycoside content. Group I, characterised by a high concentration of platycosides, was located near the west coast of Korea, whereas group II, characterised by a low concentration of platycosides, was located inland or in mountainous area. The method could be used to control the quality of balloon flower root.

Yeast α-glucosidase inhibition by isoflavones from plants of Leguminosae as an in vitro alternative to acarbose.

In the course of searching for new classes of α-glucosidase inhibitors originated from natural resources, 11 kinds of isoflavones, i.e., medicarpin (1), formononetin (2), mucronulatol (3), (3R)-calussequinone (5), (3R)-5'-methoxyvestitol (6), tectorigenin (7), biochanin A (8), tuberosin (9), calycosin (10), daidzein (11), and genistein (12), as well as a flavone, liquritigenin (4), were isolated as active principles responsible for the yeast α-glucosidase inhibitory activity from two leguminous plant extracts, i.e., the heartwood extract of Dalbergia odorifera and the roots extract of Pueraria thunbergiana. Each components (1-12) demonstrated a significantly potent inhibition on yeast α-glucosidase in a dose dependent manner when the p-nitrophenyl-α-D-glucopyranoside was used as a substrate in vitro. The concentration required for 50% enzyme inhibition (IC50) were calculated as 2.93 mM (1), 0.51 mM (2), 3.52 mM (7) 0.35 mM (8), 3.52 mM (9), 0.85 mM (11), and 0.15 mM (12) when that of reference drug acarbose was evaluated as 9.11 mM, in vitro. However, isoflavone glycosides, i.e., puerarin (13), daidzin (14), formononetin-7-O-ß-glucopyranoside (15), and genistin (16), exhibited a relatively poor inhibitory activity on yeast α-glucosidase as compared with the corresponding isoflavone (2, 11, 12), respectively.

A new esterase EstD2 isolated from plant rhizosphere soil metagenome.

Soil metagenome constitutes a reservoir for discovering novel enzymes from the unculturable microbial diversity. From three plant rhizosphere metagenomic libraries comprising a total of 142,900 members of recombinant plasmids, we obtained 14 recombinant fosmids that exhibited lipolytic activity. A selected recombinant plasmid, pFLP-2, which showed maximum lipolytic activity, was further analyzed. DNA sequence analysis of the subclone in pUC119, pELP-2, revealed an open reading frame of 1,191 bp encoding a 397-amino-acid protein. Purified EstD2 exhibited maximum enzymatic activity towards p-nitrophenyl butyrate, indicating that it is an esterase. Purified EstD2 showed optimal activity at 35 °C and at pH 8.0. The K(m) and K(cat) values were determined to be 79.4 µM and 120.5/s, respectively. The esterase exhibited an increase in enzymatic activity in the presence of 15% butanol and 15% methanol. Phylogenetic analysis revealed that the lipolytic protein EstD2 may be a member of a novel family of lipolytic enzymes. Several hypothetical protein homologs of EstD2 were found in the database. A hypothetical protein from Phenylobacterium zucineum HLK1, a close homolog of EstD2, displayed lipolytic activity when the corresponding gene was expressed in Escherichia coli. Our results suggest that the other hypothetical protein homologs of EstD2 might also be members of this novel family.

In vitro BACE-1 inhibitory phenolic components from the seeds of Psoralea corylifolia.

A new isoflavone, neocorylin ( 1) was isolated from the seeds extract of Psoralea corylifolia L. (Fabaceae), together with eight known constituents ( 2 - 9), i. e., bakuchiol ( 2), psoralen ( 3), bavachromene ( 4), isobavachromene ( 5), bavachalcone ( 6), isobavachalcone ( 7), 7,8-dihydro-8-(4-hydrophenyl)-2,2-dimethyl-2 H,6 H-[1,2- B:5,4- B']dipyran-6-one ( 8), and bavachinin ( 9). The structure of the new isoflavone 1 was elucidated as 7-hydroxy-3-[2-methyl-2-(4-methylpenten-3-yl)-2 H-chromen-6-yl]-4 H-chromen-4-one by spectroscopic analyses. Neocorylin ( 1) as well as related compounds 2, 4 - 6, 8 and 9 exhibited a significant inhibitory effect on baculovirus-expressed BACE-1 in vitro.

Selection and characterization of forest soil metagenome genes encoding lipolytic enzymes.

A metagenome is a unique resource to search for novel microbial enzymes from the unculturable microorganisms in soil. A forest soil metagenomic library using a fosmid and soil microbial DNA from Gwangneung forest, Korea, was constructed in Escherichia coli and screened to select lipolytic genes. A total of seven unique lipolytic clones were selected by screening of the 31,000-member forest soil metagenome library based on tributyrin hydrolysis. The ORFs for lipolytic activity were subcloned in a high copy number plasmid by screening the secondary shortgun libraries from the seven clones. Since the lipolytic enzymes were well secreted in E. coli into the culture broth, the lipolytic activity of the subclones was confirmed by the hydrolysis of p-nitrophenyl butyrate using culture broth. Deduced amino acid sequence analysis of the identified ORFs for lipolytic activity revealed that 4 genes encode hormone-sensitive lipase (HSL) in lipase family IV. Phylogenetic analysis indicated that 4 proteins were clustered with HSL in the database and other metagenomic HSLs. The other 2 genes and 1 gene encode non-heme peroxidase-like enzymes of lipase family V and a GDSL family esterase/lipase in family II, respectively. The gene for the GDSL enzyme is the first description of the enzyme from metagenomic screening.

5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)- 1,2-isoxazoline as a useful rice herbicide.

5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline derivative was synthesized, and its herbicidal activity was assessed under glasshouse and flooded paddy conditions. 5-(2,6-Difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 125 g of a.i. ha(-1) under greenhouse conditions. Soil application of this compound showed complete control of barnyard-grass to the fourth leaf stage at 250 g of a.i. ha(-1). Field trials indicated that this compound controlled annual weeds rapidly with a good tolerance on transplanted rice seedlings by post-emergence and soil application. This compound showed a low mammalian and environmental toxicity in various toxicological tests.

New 2-phenyl-4,5,6,7-tetrahydro-2H-indazole derivatives as paddy field herbicides.

A series of 3-chloro-2-(4-chloro-2-fluorophenyl)-4,5,6,7-tetrahydro-2H-indazole derivatives containing various substituted isoxazolinylmethoxy groups at the 5-position of the benzene ring were synthesized and their herbicidal activities assessed under greenhouse and flooded paddy conditions. Among them, compounds having a phenyl or cyano substituent at the 3-position of the 5-methyl-isoxazolin-5-yl structure demonstrated good rice selectivity and potent herbicidal activity against annual weeds at 16-63 g AI ha(-1) under greenhouse conditions. Field trials indicated that these two compounds controlled a wide range of annual weeds rapidly with a good tolerance on transplanted rice seedlings by pre-emergence application. They showed a low mammalian and environmental toxicity in various toxicological tests.