Dynamics of microbial community for X-3B wastewater decolorization coping with high-salt and metal ions conditions

In this study, decolorization of Reactive Brilliant Red X-3B wastewater by the biological process coping with high salinity and metal ions conditions was investigated, and 16S rDNA based fingerprint technique was used to investigate microbial population dynamics. Results of sequencing batch tests showed that the microbial community could keep efficient with high concentration of dye (1100 mg L⁻¹), salt (150 g L⁻¹ NaCl) and some metal ions such as Mg²⁺, Ca²⁺ (1–10 mmol L⁻¹) and Pb²⁺ (1 mmol L⁻¹). 16S rDNA-based molecular analysis techniques demonstrated that the microbial community shifted during the acclimatization process affected by salt or metal ions. Some stains similar to Bacillus, Sedimentibacter, Pseudomonas, Clostridiales, Streptomyces and some uncultured clones acted for the dynamic succession, supposed as potential decolorization bacteria. This study provided insights on the decolorization capability and the population dynamic shifts during decolorization process of azo dye wastewater coping with salt and metal ions.     

Production and synthetic dyes decolourization capacity of a recombinant laccase from Pichia pastoris

Aims:  To produce and purify a recombinant laccase from Pichia pastoris and to test its ability in decolourization of synthetic dyes.
Methods and Results:  A cDNA encoding for a laccase was isolated from Pycnoporus sanguineus and was expressed in P. pastoris strain SMD1168H under the control of the alcohol oxidase (AOX1) promoter. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as cultivation temperature, pH, copper concentration and methanol concentration, were investigated. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a molecular mass of about 62·8 kDa. The purified enzyme showed a similar behaviour to the native laccase produced by P. sanguineus . Four different synthetic dyes including azo, anthraquinone, triphenylmethane and indigo dyes could be efficiently decolourized by the purified recombinant laccase without the addition of redox mediators.
Conclusions:  Heterologous production of P. sanguineus laccase in P. pastoris was successfully achieved. The purified recombinant laccase could efficiently decolourize synthetic dyes in the absence of mediators.
Significance and Impact of the Study:  This study is the first report on the synthetic dye decolourization by the recombinant P. sanguineus laccase. The decolourization capacity of this recombinant enzyme suggested that it could be a useful biocatalyst for the treatment of dye-containing effluents.     

Cytogenetics of Bolinus brandaris and phylogenetic inferences within the Muricidae (Mollusca: Gastropoda)

The purple dye murex, Bolinus brandaris (Linnaeus, 1758), is a muricid gastropod common throughout the Mediterranean and along the Moroccan and Portuguese Atlantic coasts. In the present study, we confirmed the diploid chromosome number of 2 n  = 70 for this species, and established for the first time the karyotype, which comprised 12 metacentric, 15 submetacentric and eight subtelocentric chromosome pairs. To facilitate cytotaxonomic comparisons, we carried out a comparative karyological analysis through multidimensional scaling between B. brandaris and three other 2 n  = 70 muricid species ( Hexaplex trunculus , Ocenebra erinaceus , and Stramonita haemastoma ) for which chromosomal measurements have been previously published. The interpretation of the ideograms and the statistical analysis highlighted the closest similarity of B. brandaris and H. trunculus compared to S. haemastoma and O. erinaceus . Indeed, B. brandaris and H. trunculus showed the smallest dissimilarities both for relative length and arm ratio, with O. erinaceus presenting intermediate values, whereas the highest dissimilarities were found between H. trunculus and S. haemastoma for both data. The karyotypes of B. brandaris and H. trunculus (subfamily Muricinae) presented the highest proportions of metacentric chromosomes compared to the other two muricids analysed, suggesting that those karyotypes could be considered primitive within the 2 n  = 70 Muricidae studied so far.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 185–193.     

Decolorization of diazo dye Direct Red 81 by a novel bacterial consortium

Summary Samples collected from various effluent-contaminated soils in the vicinities of dyestuff manufacturing units of Ahmedabad, India, were studied for screening and isolation of organisms capable of decolorizing textile dyes. A novel bacterial consortium was selected on the basis of rapid decolorization of Direct Red 81 (DR 81), which was used as model dye. The bacterial consortium exhibited 90% decolorization ability within 35 h. Maximum rate of decolorization was observed when starch (0.6 g l⁻¹) and casein (0.9 g l⁻¹) were supplemented in the medium. Decolorization of DR 81 was monitored by high performance thin layer chromatography, which indicated that dye decolorization was due to its degradation into unidentified intermediates. The optimum dye-decolorizing activity of the culture was observed at pH 7.0 and incubation temperature of 37 °C. Maximum dye-decolorizing efficiency was observed at 200 mg l⁻¹ concentration of DR 81. The bacterial consortium had an ability to decolorize nine other structurally different azo dyes.     

Fluorescent carbon nanoparticles from Citrus sinensis as efficient sorbents for pollutant dyes

Here, we report a simple, green and economic process for the synthesis of highly fluorescent carbon nanoparticles (CPs) through low‐temperature carbonization of a fruit waste, Citrus sinensis peel. This approach allows the large‐scale production of aqueous CPs dispersions without any additives and post‐treatment processes. The as‐prepared CPs were of small particle size, exhibited bright blue fluorescence under UV irradiation (λ_max = 365 nm) with excellent colloidal stability in water. The chemical composition, structure and morphology of the as‐prepared CPs were analyzed using various spectroscopic techniques such as X‐ray diffraction, transmission electron microscopy and raman spectroscopy. The formed CPs were turbostratic in nature, with a large number of functional groups on the surface. We explored the adsorption characteristics of the formed CPs for wastewater treatment. Because of the negative surface of the CPs, as evident from the zeta value, it is possible to use them for selective adsorption of the cationic dye methylene blue from a mixture of dyes. The equilibrium adsorption isotherm revealed that the Langmuir model better describes the adsorption process than the Freundlich model. As‐prepared CPs rapidly adsorbed ~84% of the methylene blue within 1 min and can be regenerated and used repeatedly. Copyright © 2016 John Wiley & Sons, Ltd.     

大黄鱼耐低温性状相关微卫星标记的筛选

鱼类的耐低温性状是一种重要的经济性状。为了初步分析大黄鱼的耐低温性状, 文章采用15对荧光微卫星标记, 以SSR-PCR方法对大黄鱼低温耐受组和正常对照组F₁代共40个个体进行了耐低温性状遗传差异分析。结果显示, 标记LYC0002在两组样品中共扩增出5个等位基因(片段大小分别为112 bp、110 bp、108 bp、106 bp和104 bp), 其中LYC00021_{12 bp}等位基因在低温耐受组的出现频率达60%, 而在正常对照组中的频率为零, 表明该等位基因对大黄鱼的温度敏感特性有较明显的偏好性, 可能与某种耐低温基因存在一定的连锁关系。此外, 对LYC0002_{106 bp、}LYC0002_{108 bp}、LYC0002_{110 bp} 和 LYC0002_{112 bp} 4个等位基因分别进行了回收、克隆及测序。序列比对结果显示, LYC0002_{112 bp}等位基因含有10个(CA)重复单元, 而其他3个等位基因依次缺失1个(CA)重复单元, 说明LYC0002在本研究样本中的突变方式为微卫星逐步突变模型(Stepwise mutation model, SMM)。     

High‐Performance,Transparent, Dye‐Sensitized Solar Cells for See‐Through Photovoltaic Windows

Dye‐sensitized solar cells (DSCs) have attracted great interest as one of the most promising photovoltaic technologies, and transparent DSCs show potential applications as photovoltaic windows. However, the competition between light absorption for photocurrent generation and light transmittance for obtaining high transparency limits the performance of transparent DSCs. Here, transparent DSCs exhibiting a high light transmittance of 60.3% and high energy conversion efficiency (3.66%) are reported. The strategy is to create a cocktail system composed of ultraviolet and near‐infrared dye sensitizers that selectively and efficiently harvest light in the invisible or low‐eye‐sensitivity region while transmitting light in high‐eye‐sensitivity regions. This new design provides a reasonable approach for realizing high efficiency and transparency DSCs that have potential applications as photovoltaic windows.     

Design of a New Energy‐Harvesting Electrochromic Window Based on an Organic Polymeric Dye,a Cobalt Couple,and PProDOT‐Me2

A new design for an energy‐harvesting electrochromic window (EH‐ECW) based on the fusion of two technologies, organic electrochromic windows and dye‐sensitized solar cells (DSSCs), is presented. Unlike other power‐generating smart windows, such as photoelectrochromic devices that are passive and only contain two states (i.e., a closed‐circuit colored state and an open‐circuit bleaching state), EH‐ECW allows active tuning of the transmittance by varying the applied potential and it functions as a photovoltaic cell based on a DSSC. The resulting device demonstrates a fast switching rate of 1 s in both the bleaching and coloring processes through the use of an electrochromic polymer as a counter electrode layer. To increase the transmittance of the device, a cobalt redox couple and a light‐colored, yet efficient, organic dye are used. The organic dye contains a polymeric structure that contributes to the high cyclic stability. The device exhibits a power conversion efficiency (PCE) of 4.5% (100 mW cm^‐2) under AM 1.5 irradiation, a change in transmittance of 34% upon applied potential, and shows only 3% degradation in the PCE after 5000 cycles.