Production of arabitol by yeasts: current status and future prospects

Arabitol belongs to the pentitol family and is used in the food industry as a sweetener and in the production of human therapeutics as an anticariogenic agent and an adipose tissue reducer. It can also be utilized as a substrate for chemical products such as arabinoic and xylonic acids, propylene, ethylene glycol, xylitol and others. It is included on the list of 12 building block C3‐C6 compounds, designated for further biotechnological research. This polyol can be produced by yeasts in the processes of bioconversion or biotransformation of waste materials from agriculture, the forest industry (l ‐arabinose, glucose) and the biodiesel industry (glycerol). The present review discusses research on native yeasts from the genera Candida, Pichia, Debaryomyces and Zygosaccharomyces as well as genetically modified strains of Saccharomyces cerevisiae which are able to utilize biomass hydrolysates to effectively produce l ‐ or d ‐arabitol. The metabolic pathways of these yeasts leading from sugars and glycerol to arabitol are presented. Although the number of reports concerning microbial production of arabitol is rather limited, the research on this topic has been growing for the last several years, with researchers looking for new micro‐organisms, substrates and technologies.     

呼肠孤病毒Ⅲ型免疫荧光检测方法的建立及初步应用

目的 建立呼肠孤病毒Ⅲ型（Reo3）免疫荧光（IFA）检测方法,应用于人用动物源性生物材料及生物制品外源Reo3的检测。方法滴定病毒TCID50,筛选Reo3敏感细胞,依据国标IFA法制备抗原片,方阵法滴定免疫荧光素最佳工作浓度。并进行特异性、敏感性和稳定性试验。结果选取BSC-1细胞作为Reo3敏感细胞,病毒感染力滴度（TCID50）为10-5.8/mL;免疫荧光素最佳工作浓度为1∶100;与小鼠鼠痘（Ect）病毒、小鼠肝炎（MHV）病毒均无交叉反应;稳定性和敏感性试验显示,不同时间IFA检测灵敏度均为1∶1280;可检测到的病毒滴度最低为10-4.1/mL。结论建立的IFA法敏感性、特异性强,稳定性好,可用于人用动物源性生物材料及生物制品Reo3的检测。     

Synthesis of Partially Graphitic Ordered Mesoporous Carbons with High Surface Areas

Graphitic carbons with ordered mesostructure and high surface areas (of great interest in applications such as energy storage) have been synthesized by a direct triblock‐copolymer‐templating method. Pluronic F127 is used as a structure‐directing agent, with a low‐molecular‐weight phenolic resol as a carbon source, ferric oxide as a catalyst, and silica as an additive. Inorganic oxides can be completely eliminated from the carbon. Small‐angle XRD and N₂ sorption analysis show that the resultant carbon materials possess an ordered 2D hexagonal mesostructure, uniform bimodal mesopores (about 1.5 and 6 nm), high surface area (～1300 m²/g), and large pore volumes (～1.50 cm³/g) after low‐temperature pyrolysis (900 °C). All surface areas come from mesopores. Wide‐angle XRD patterns demonstrate that the presence of the ferric oxide catalyst and the silica additive lead to a marked enhancement of graphitic ordering in the framework. Raman spectra provide evidence of the increased content of graphitic sp² carbon structures. Transmission electron microscopy images confirm that numerous domains in the ordered mesostructures are composed of characteristic graphitic carbon nanostructures. The evolution of the graphitic structure is dependent on the temperature and the concentrations of the silica additive, and ferric oxide catalyst. Electrochemical measurements performed on this graphitic mesoporous carbon when used as an electrode material for an electrochemical double layer capacitor shows rectangular‐shaped cyclic voltammetry curves over a wide range of scan rates, even up to 200 mV/s, with a large capacitance of 155 F/g in KOH electrolyte. This method can be widely applied to the synthesis of graphitized carbon nanostructures.     

Ligand‐Assisted Assembly Approach to Synthesize Large‐Pore Ordered Mesoporous Titania with Thermally Stable and Crystalline Framework

A novel ligand‐assisted assembly approach is demonstrated for the synthesis of thermally stable and large‐pore ordered mesoporous titanium dioxide with a highly crystalline framework by using diblock copolymer poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) as a template and titanium isopropoxide (TIPO) as a precursor. Small‐angle X‐ray scattering, X‐ray diffraction (XRD), transmission electron microscopy (TEM), high‐resolution scanning electron microscopy, and N₂‐sorption measurements indicate that the obtained TiO₂ materials possess an ordered primary cubic mesostructure with large, uniform pore diameters of about 16.0 nm, and high Brunauer–Emmett–Teller surface areas of ～112 m² g^?1, as well as high thermal stability (～700 °C). High resolution TEM and wide‐angle XRD measurements clearly illustrate the high crystallinity of the mesoporous titania with an anatase structure in the pore walls. It is worth mentioning that, in this process, in addition to tetrahydrofuran as a solvent, acetylacetone was employed as a coordination agent to avoid rapid hydrolysis of the titanium precursor. Additionally, stepped evaporation and heating processes were adopted to control the condensation rate and facilitate the assembly of the ordered mesostructure, and ensure the formation of fully polycrystalline anatase titania frameworks without collapse of the mesostructure. By employing the obtained mesoporous and crystallized TiO₂ as the photoanode in a dye‐sensitized solar cell, a high power‐conversion efficiency (5.45%) can be achieved in combination with the N719 dye, which shows that this mesoprous titania is a great potential candidate as a catalyst support for photonic‐conversion applications.     

Thermoelectric Nanostructures: From Physical Model Systems towards Nanograined Composites

Thermoelectric materials could play an increasing role for the efficient use of energy resources and waste heat recovery in the future. The thermoelectric efficiency of materials is described by the figure of merit ZT = (S²σT)/κ (S Seebeck coefficient, σ electrical conductivity, κ thermal conductivity, and T absolute temperature). In recent years, several groups worldwide have been able to experimentally prove the enhancement of the thermoelectric efficiency by reduction of the thermal conductivity due to phonon blocking at nanostructured interfaces. This review addresses recent developments from thermoelectric model systems, e.g. nanowires, nanoscale meshes, and thermionic superlattices, up to nanograined bulk‐materials. In particular, the progress of nanostructured silicon and related alloys as an emerging material in thermoelectrics is emphasized. Scalable synthesis approaches of high‐performance thermoelectrics for high‐temperature applications is discussed at the end.     

Polymer-based Preparation of Soil Inoculants: Applications to Arbuscular Mycorrhizal Fungi

Arbuscular mycorrhizal fungi is an important group of soil microorganisms which form beneficial symbiotic associations with roots with a wide range of plants thus improving plant growth, nutrition and health. This paper reviews the current status of preparation and formulation of mycorrhizal inoculum applying polymer materials with determined characteristics. The most widely used methods are based on the entrapment of fungal materials in natural polysaccharide gels. The potential of such inoculant preparations is illustrated by various studies which include immobilization of mycorrhized root pieces, vesicles and spores, in some cases co-entrapped with other plant beneficial microorganisms. Suggestions for further research in this field are also discussed.     

From cluster calculations to molecular materials: a mixed pseudopotential approach to modeling mixed-valence systems

In this paper we present a technique for finding an appropriate parameterization of ultrasoft pseudopotentials for modeling mixed-valence materials. For the example of hexacyanometallate molecular building blocks, we show how ionic cluster calculations can be used to determine a set of parameters for the metal centers. Pseudopotentials chosen in such a way are then shown to be suitable for periodic calculations of the corresponding mixed-valence materials (e.g., Prussian Blue).This work was originally presented at the Modelling and Design of Molecular Materials conference in Wrocaw, Poland.