RESUMO
The Lebedev process, in which ethanol is catalytically converted into 1,3-butadiene, is an alternative process for the production of this commodity chemical. Silica-magnesia (SiO2-MgO) is a benchmark catalyst for the Lebedev process. Among the different preparation methods, the SiO2-MgO catalysts prepared by wet-kneading typically perform best owing to the surface magnesium silicates formed during wet-kneading. Although the thermal treatment is of pivotal importance as a last step in the catalyst preparation, the effect of the calcination temperature of the wet-kneaded SiO2-MgO on the Lebedev process has not been clarified yet. Here, we prepared and characterized in detail a series of wet-kneaded SiO2-MgO catalysts using varying calcination temperatures. We find that the thermal treatment largely influences the type of magnesium silicates, which have different catalytic properties. Our results suggest that the structurally ill-defined amorphous magnesium silicates and lizardite are responsible for the production of ethylene. Further, we argue that forsterite, which has been conventionally considered detrimental for the formation of ethylene, favors the formation of butadiene, especially when combined with stevensite.
RESUMO
A Gram-staining-positive actinobacterium, designated strain 1MR-8(T), was isolated from the rhizoplane of ginseng and its taxonomic status was determined using a polyphasic approach. The isolate formed long chains of spores that were straight, cylindrical and smooth-surfaced. Strain 1MR-8(T) grew at 10-37 °C (optimum 28 °C), whilst no growth was observed at 45 °C. The pH range for growth was 4.0-11.0 (optimum pH 6.0-8.0) and the NaCl range for growth was 0-7% (w/v) with optimum growth at 1% (w/v). Strain 1MR-8(T) had cell-wall peptidoglycans based on ll-diaminopimelic acid. Glucose, mannose and ribose were the whole-cell sugars. The predominant isoprenoid quinones were MK-9 (H4), MK-9 (H6) and MK-9 (H8) and the major fatty acids were anteiso-C(15:0), iso-C(15:0), anteiso-C(17:0) and iso-C(16:0). 16S rRNA gene sequencing studies showed that the novel strain was closely related to the type strains of Streptomyces caeruleatus GIMN4(T), Streptomyces curacoi NRRL B-2901(T), Streptomyces capoamus JCM 4734(T) and Streptomyces coeruleorubidus NBRC 12761(T) with similarities of 98.8%. However, DNA-DNA relatedness, as well as physiological and biochemical analyses, showed that strain 1MR-8(T) could be differentiated from its closest phylogenetic relatives. It is proposed that this strain should be classified as a representative of a novel species of the genus Streptomyces, with the suggested name Streptomyces panaciradicis sp. nov. The type strain is 1MR-8(T) (â=âKACC 17632(T)â=âNBRC 109811(T)).
Assuntos
Panax/microbiologia , Filogenia , Streptomyces/classificação , Composição de Bases , Celulases/genética , DNA Bacteriano/genética , Ácido Diaminopimélico/química , Ácidos Graxos/química , Glucosidases/metabolismo , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Peptidoglicano/química , RNA Ribossômico 16S/genética , Rizosfera , Análise de Sequência de DNA , Streptomyces/genética , Streptomyces/isolamento & purificação , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
An exopolysaccharide-producing bacterium, designated strain DRP 35(T), was isolated from the rhizosphere soil of a medicinal herb, Angelica sinensis, at Geumsan in Korea. Cells were Gram-staining-negative, non-motile, catalase-positive and oxidase-negative short rods. The isolate grew aerobically from 15 to 45 °C (optimum 30 °C), pH 3.5-7.0 (optimum pH 5.0) and in the presence of 0-1.0% (w/v) NaCl. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain DRP 35(T) belongs to the genus Terriglobus in the phylum Acidobacteria with a sequence similarity of 97.2% and 97.0% to Terriglobus saanensis SP1PR4(T) and Terriglobus roseus KBS63(T), respectively. The genomic DNA G+C content was 62.1 mol%. DNA-DNA relatedness between strain DRP 35(T) and the type strains of the other species of the genus Terriglobus, T. saanensis SP1PR4(T) and T. roseus KBS63(T), were 24.6 and 17.2%, respectively. The predominant menaquinone was MK-8. Major fatty acids were iso-C(15 : 0), C(16 : 1)ω7c and C(16â: 0). The polar lipids were phosphatidylethanolamine, unidentified aminophospholipid and unknown phospholipids. On the basis of polyphasic analysis from this study, strain DRP 35(T) represents a novel species of the genus Terriglobus for which the name Terriglobus tenax sp. nov. is proposed. The type strain is DRP 35(T) (â=âKACC 16474(T)â=âNBRC 109677(T)).
Assuntos
Acidobacteria/classificação , Angelica sinensis/microbiologia , Filogenia , Rizosfera , Microbiologia do Solo , Acidobacteria/genética , Acidobacteria/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Fosfatidiletanolaminas/química , Fosfolipídeos/química , Plantas Medicinais/microbiologia , RNA Ribossômico 16S/genética , República da Coreia , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
BACKGROUND: Surgery has been the classical treatment of pectus carinatum (PC), though compressive orthotic braces have shown successful results in recent years. We propose a non-operative approach using a lightweight, patient-controlled dynamic chest-bracing device. MATERIALS AND METHODS: Eighteen patients with PC were treated between July 2008 and June 2009. The treatment involved fitting of the brace, which was worn for at least 20 hours per day for 6 months. Their degree of satisfaction (1, no correction; 4, remarkable correction) was measured at 12 months after the initiation of the treatment. RESULTS: Thirteen (72.2%) patients completed the treatment (mean time, 4.9±1.4 months). In patients who completed the treatment, the mean overall satisfaction score was 3.73±0.39. The mean satisfaction score was 4, and there was no recurrence of pectus carinatum in patients who underwent the treatment for at least 6 months. Minimal recurrence of pectus carinatum after removal of the compressive brace occurred in 5 (38.5%) patients who stopped wearing the compressive brace at 4 months. CONCLUSION: Compressive bracing results in a significant improvement in PC appearance in patients with an immature skeleton. However, patient compliance and diligent follow-up appear to be paramount for the success of this method of treatment. We currently offer this approach as a first-line treatment for PC.
RESUMO
In this study, a strategy was developed for the synthesis of nano-sized, silica-ceria, core-shell composites in a water-oil (W/O) microemulsion consisting of water, heptane and the binary surfactants AOT (sulfosuccinic acid bis (2-ethylhexyl) ester sodium salt) and NP-5 (polyoxyethylene (5) nonylphenyl ether). The core-shell, silica-ceria particles were prepared in a stepwise procedure: (1) the precipitation of the core-silica particles in a W/O microemulsion and (2) the surface precipitation of ceria on the core silica dispersed over the microemulsion. The composition of the binary surfactant greatly influenced the growth rate of the core-silica particles. The virial coefficient of diffusion was utilized to estimate the effect of the surfactant composition on the degree of intermicellar interaction that is important for the growth rate of the silica along with the flexibility of the micellar interface and the structure of the water domain. The deposition of the ceria on the core silica was not straightforward because the bulk and surface precipitation competed with each other. The promotion of surface precipitation was attempted by: (1) chemically modifying the silica surface with an organoamine group and (2) slowing down the precipitation rate of the ceria in a semi-batch operation. These attempts successfully produced the nano-sized silica-ceria, core-shell particles, which were evidenced through the TEM, XPS and zeta potential analysis.
RESUMO
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 degrees C, 0.4 g/ml (oil), 1:9 (oil to alcohol, molar ratio) and 2h reaction time. The physical and chemical properties of the catalyst were characterized by XRD, Raman spectrometer, BET and NH(3)-TPD.
Assuntos
Ácidos/química , Óxidos/química , Tungstênio/química , Zircônio/química , Biocatálise , Esterificação , Difração de Raios XRESUMO
Vegetables and fruits are essential components of the human diet as they are sources of vitamins, minerals, and fiber and provide antioxidants that prevent chronic diseases. Our goal is to improve durable nutritional quality of tomato fruit. We developed transgenic tomatoes expressing yeast S-adenosylmethionine decarboxylase (ySAMdc) gene driven by a fruit-specific E8 promoter to investigate the role of polyamines in fruit metabolism. Stable integration of E8-ySAMdc chimeric gene in tomato genome led to ripening-specific accumulation of polyamines, spermidine (Spd) and spermine (Spm), which in turn affected higher accumulation of glutamine, asparagine, and organic acids in the red fruit with significant decrease in the contents of valine, aspartate, sucrose, and glucose. The metabolite profiling analysis suggests that Spd/Spm are perceived as "signaling" organic-N metabolites by the fruit cells, resulting in the stimulation of carbon sequestration; enhanced synthesis of biomolecules; increased acid to sugar ratio, a good attribute for the fruit flavor; and in the accumulation of another "vital amine," choline, which is an essential micronutrient for brain development. A limited transcriptome analysis of the transgenic fruit that accumulate higher polyamines revealed a large number of differentially expressed genes, about 55% of which represented discrete functional categories, and the remaining 45% were novel, unknown, or unclassified: amino acid biosynthesis, carotenoid biosynthesis, cell wall metabolism, chaperone family, flavonoid biosynthesis, fruit ripening, isoprenoid biosynthesis, polyamine biosynthesis, signal transduction, stress/defense-related, transcription, translation, and vacuolar function. There was a good correspondence between some gene transcripts and their protein products, but not in the case of the tonoplast intrinsic protein, which showed post-transcriptional regulation. Higher metabolic activity of the transgenic fruit is reflected in higher respiratory activity, and upregulation of chaperones and mitochondrial cytochrome oxidase transcripts compared to the control. These transgenic plants are a new resource to understand the role of Spd/Spm in fruit biology. Transcriptome analysis and metabolic profiles of Spd/Spm accumulating, transgenic fruit suggest the presence of an intricate regulation and interconnection between certain metabolic pathways that are revived when Spd and Spm likely reach a certain threshold. Thus, polyamines act as antiapoptotic regulatory molecules and are able to revive metabolic memory in the tomato fruit.