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Chen Y.-G.,Huazhong Agricultural University | Chen Y.-G.,Spice and Beverage Research Institute | Gu F.-L.,Spice and Beverage Research Institute | Gu F.-L.,Key Laboratory of Genetic Resources Utilization of Spice and Beverage Crops | And 8 more authors.
Current Microbiology | Year: 2015

A Gram-positive bacterium, designated strain XY18T, was isolated from a cured vanilla bean in Hainan province, China. Cells were rod-shaped, endospore producing, and peritrichous flagella. Strain XY18T grew at salinities of 0–8 % (w/v) NaCl (optimally 1–4 %), pH 4.0–8.0 (optimally 5.0–7.0 %) and temperature range 20–45 °C (optimally 28–35 °C). The predominant menaquinone was MK-7. The major cellular fatty acids were anteiso-C15:0, iso-C15:0, anteiso-C17:0, and iso-C17:0. Phylogenetic analysis based on 16S rRNA gene sequence indicated that strain XY18T was a member of the genus Bacillus, and closely related to B. amyloliquefaciens NBRC 15535T and B. siamensis PD-A10T, with 99.1 and 99.2 % sequence similarity, respectively. However, the DNA–DNA hybridization value between strain XY18T and B. amyloliquefaciens NBRC 15535T was 35.7 %. The genomic DNA G+C content of strain XY18T was 46.4 mol%, significantly differed from B. siamensis PD-A10T (41.4 %), which was higher than the range of 4 % indicative of species. On the basis of polyphasic taxonomic study, including phenotypic features, chemotaxonomy, and phylogenetic analyses, strain XY18T represents a novel species within the genus Bacillus, for which the name Bacillusvanillea sp. nov. is proposed. The type strain is XY18T (=CGMCC 8629 = NCCB 100507). © 2014, Springer Science+Business Media New York. Source

Chen Y.,Spice and Beverage Research Institute | Chen Y.,Huazhong Agricultural University | Chen Y.,Key Laboratory of Genetic Resources Utilization of Spice and Beverage Crops | Gu F.,Spice and Beverage Research Institute | And 8 more authors.
Applied and Environmental Microbiology | Year: 2015

Vanilla beans were analyzed using biochemical methods, which revealed that glucovanillin disperses from the inner part to the outer part of the vanilla bean during the curing process and is simultaneously hydrolyzed by β-D-glucosidase. Enzymatic hydrolysis was found to occur on the surface of the vanilla beans. Transcripts of the β-D-glucosidase gene (bgl) of colonizing microorganisms were detected. The results directly indicate that colonizing microorganisms are involved in glucovanillin hydrolysis. Phylogenetic analysis based on 16S rRNA gene sequences showed that the colonizing microorganisms mainly belonged to the Bacillus genus. bgl was detected in all the isolates and presented clustering similar to that of the isolate taxonomy. Furthermore, inoculation of green fluorescent protein-tagged isolates showed that the Bacillus isolates can colonize vanilla beans. Glucovanillin was metabolized as the sole source of carbon in a culture of the isolates within 24 h. These isolates presented unique glucovanillin degradation capabilities. Vanillin was the major volatile compound in the culture. Other compounds, such as α-cubebene, β-pinene, and guaiacol, were detected in some isolate cultures. Colonizing Bacillus isolates were found to hydrolyze glucovanillin in culture, indirectly demonstrating the involvement of colonizing Bacillus isolates in glucovanillin hydrolysis during the vanilla curing process. Based on these results, we conclude that colonizing Bacillus isolates produce β-D-glucosidase, which mediates glucovanillin hydrolysis and influences flavor formation. © 2015, American Society for Microbiology. Source

Li C.,Deakin University | Li Y.,Deakin University | Li Y.,Agricultural Product Processing Research Institute | She X.,Deakin University | And 5 more authors.
Composites Science and Technology | Year: 2015

We report the synergistic reinforcement and deformation of polyvinyl alcohol (PVA)/graphene/montmorillonite clay (MMT) composites with the tensile properties being improved greatly. Particularly, the tensile strength and modulus of PVA composite with 0.9 wt% graphene and 0.3 wt% of MMT were improved by more than 58% and 43% when compared to the neat PVA, respectively, and were at least 10% higher than the enhanced sum of dual PVA composites with 0.9 wt% graphene and 0.3 wt% MMT. This reinforcement was resulted from the good dispersion and effective interfacial interactions as confirmed from morphology investigation, increased glass transition temperature and the shift of O-H stretching. When there were no fillers i.e. in situ reduced graphene (IRG) or MMT or their loading was low, high alignment of PVA could be observed, with increased crystallinity, melting point, lamellae thickness but narrowed crystallite size distribution. The synergistic reinforcement of PVA achieved from combined incorporation of IRG and MMT will pave the way for the development of stronger PVA composites in various applications. © 2015. Source

Luo Y.,Agricultural Product Processing Research Institute | He D.,Southern Research Institute | Tao J.,Agricultural Product Processing Research Institute | Zhao P.,Agricultural Product Processing Research Institute | And 5 more authors.
Polymer Composites | Year: 2016

The dispersion behaviors of graphene oxide (GO) and poly(sodium p-styrenesulfonate) (PSS) modified silica doped into the natural rubber (NR) matrix are revealed in this study, respectively. The NR composites are fabricated by latex compounding technology. We find that GO as a two-dimensional dispersant can link with silica through its oxide groups and form a layer of silica on the surface, which improves the silica distribution homogeneity. In comparison, PSS as a one-dimensional dispersant twins silica particles and forms a matrix consisting of stick-like composite with fillers. Both GO and PSS can improve the dispersibility of silica in the NR composites, and the tensile and tear strengths of the NR/GO/SiO2 and NR/PSS/SiO2 are improved compared to those of the NR/SiO2 composites. This strategy of modifying silica with GO and PSS is proven being an effective approach for the development of elastic nanocomposites. © 2016 Society of Plastics Engineers. Source

Zhang F.Q.,Agricultural Product Processing Research Institute | Wang Y.Z.,Agricultural Product Processing Research Institute | Chen M.,Agricultural Product Processing Research Institute | Huang M.F.,Agricultural Product Processing Research Institute | Zeng R.Z.,Rubber Research Institute of China
Advanced Materials Research | Year: 2014

In this work, the rheological behavior of uncured natural rubber with different initial moisture contents dried by microwave was studied using RPA under frequency sweep and strain sweep modes. It can be seen from the results that the variation trend of viscous torque S' versus sweep frequency kept with the trend of elastic torque S' versus sweep frequency. Moreover, the viscous torque S' values were lower than those for elastic torque S', a good linear relation curve was obtained by plotting elastic torque S' versus sweep frequency. The curve of storage shear modulus G' versus sweep strain presented a linear relationship, showed a linear viscoelastic behavior of uncured natural rubber with different initial moisture contents. This may be explained by the degradation of molecular chains of natural rubber and the van der waals forces between them. © (2014) Trans Tech Publications, Switzerland. Source

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