The spatio-temporal diversity and succession of microbial community and its environment driving factors during stacking fermentation of Maotai-flavor baijiu.

Stacking fermentation is an important stage of microbial expansion and enrichment in the brewing process of Maotai-flavor baijiu and has an important impact on quality. However, the structure and succession of microbial communities at different spatial points of fermented grains, as well as the key environmental factors driving community assembly, remain unclear. Here, we analyzed spatio-temporal similarities and differences in the microbial community structure and succession during 1-6 rounds of stacking fermentation of Maotai-flavor baijiu. The microbial diversity and richness in the pile center were higher than those at the pile surface. The dominant bacterial genus changed from Lactobacillus to Acetobacter, while the dominant fungal genus Pichia was gradually replaced by Candida, however, some microorganisms (Acetobacter, Thermoascus) could not occupy community dominance in both the pile surface and the pile center of fermented grains. Most of the biomarkers (Kroppenstedtia, Thermomyces, etc.) of the pile surface showed thermostable or thermophilic characteristics, while most biomarkers (Aspergillus, Hyphopicia, etc.) of the pile center were functional microorganisms. Furthermore, pH and moisture were the main environmental driving factors of community construction at the pile surface and the pile center, respectively, with starch and reducing sugars having a greater impact on the microbial community assembly of the pile center than that of the pile surface. The main differences in the metabolic pathways of the dominant bacterial genera of the pile surface and the pile center were concentrated around cell growth and death, amino acids, leading to enrichment and growth of microbial communities at the pile surface and nitrogen utilization at the pile center, respectively. This study reveals the spatio-temporal differences in microbial community structure, succession and corresponding environmental driving factors during stacking fermentation, which will provide guidance for regulating the microbial community diversity to produce high-quality Maotai-flavor baijiu.

High magneto-optical characteristics of Holmium-doped terbium gallium garnet crystal.

Magneto-optical characteristics of a new magneto-active material, (Tb(1-x)Hox)3Ga5O12 crystal, have been grown by the Czochralski (Cz) method. A high value of the Verdet constant was obtained at room temperature-namely, 214.9 and 77.8 rad·m-1 T-1 for 632.8 and 1064 nm, respectively. The Verdet constant of the Ho-doped terbium gallium garnet crystal at 1064 nm is about 2 times higher than that of terbium gallium garnet crystal. High value of magneto-optical figure-of-merit makes it an attractive next-generation magneto-optics material for high-power Faraday isolators.

Assessment of dietary intake of polychlorinated dibenzo-p-dioxins and dibenzofurans and dioxin-like polychlorinated biphenyls from the Chinese Total Diet Study in 2011.

The concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in food samples from the fifth Chinese Total Diet Study (TDS) performed in 2011. A total of 152 composite samples from various food groups were analyzed by high resolution gas chromatography-high resolution mass spectrometer (HRGC-HRMS). The dietary intakes of PCDD/Fs and dl-PCBs were subsequently estimated for the adult from various regions in China. The mean dietary intake of PCDD/Fs and dl-PCBs was 20.1 pg TEQ kg(-1) bw month(-1) (WHO-TEF of 1998) within a range of 4.2 pg TEQ kg(-1) bw month(-1) to 53.7 pg TEQ kg(-1) bw month(-1) which were all much lower than the provisional tolerable monthly intake (PTMI) established by Joint FAO/WHO Expert Committee on Food Additives (JECFA). By comparing with results from previous Chinese TDS, a decline of the average dietary intake was observed from 2000 to 2011, but a notable elevation was observed in some regions partly stem from increasing contamination levels in certain foods.

Fabrication and characterization of cerium-doped terbium gallium garnet with high magneto-optical properties.

High optical quality (Tb((1-x))Ce(x))3Ga5O12 (TCGG) single crystal has been grown by the Czochralski method. The optical and magneto-optical properties of the TCGG are analyzed in detail and the Verdet constant (V) of TCGG is compared with that of undoped terbium gallium garnet (TGG) crystal. TCGG presents a very high transmittance, particularly in the visible-near infrared (VIS-NIR) region, and its V is obviously larger than that of TGG in the VIS-NIR region. The figure of merit and optical features point out the superior characteristics of TCGG with respect to TGG.

Assessment on dioxin-like compounds intake from various marine fish from Zhoushan Fishery, China.

Sea fish consuming is an important intake source of dioxin-like compounds, especially for the coastal residents. To assess the intake levels of these contaminants from sea fish and to provide risk-based consumption advice, concentrations of 17 polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and 12 dioxin-like polychlorinated biphenyls (dl-PCBs) were measured in 32 commonly consumed fish species from Zhoushan Fishery, China. Due to the different accumulation influenced by fat content, feed habits and living zone in the sea area, the levels of PCDDs, PCDFs and dl-PCBs in different fish species varied significantly ranging from 0.002 to 0.078pg WHO-TEQ/g fresh weight, from 0.002 to 0.553pg WHO-TEQ/g fresh weight and from 0.003 to 2.059pg WHO-TEQ/g fresh weight, respectively. Based on mean fish consuming rate in China, the estimated maximum possible dioxin-like compounds intake through different fish species ranged from 0.26 to 65.61pgTEQkg(-1)bwmonth(-1). Bullet mackerel has the highest monthly intake level which was much higher than other fish species and very close to the provisional tolerable monthly intake (70pgTEQkg(-)(1)bwmonth(-)(1)) proposed by the Joint FAO/WHO Expert Committee on Food Additives. Hence, comparing to other fish species, the consumption of Bullet mackerel from Zhoushan Fishery should be cautious to reduce the potential health risk.