Exploring of seasonal dynamics of microbial community in multispecies fermentation of Shanxi mature vinegar.

The constituents of fermentation foods vary seasonally and the microbiota plays a crucial role in metabolites formation. Here, the diversity and succession of microbiota of Shanxi mature vinegar produced with solid-solid fermentation craft have been investigated by Illumina Hiseq sequencing in both summer and winter. Obvious differences were observed in the structure of microbiota between summer and winter, and the bacterial community showed a significant difference (P < 0.05). Alpha diversity analysis showed that the diversity and richness of bacterial community were basically higher than that of fungal community in both summer and winter. For bacterial community, Lactobacillus and Limosilactobacillus were the two major group bacteria in the fermentation process of Shanxi mature vinegar in summer, and they dominated in acetic acid fermentation and alcoholic fermentation stages, respectively. Lactobacillus and Acetobacter were the two major group bacteria during the fermentation of Shanxi mature vinegar in winter. Saccharomyces, Saccharomycopsis, and Issatchenkia were the main yeasts in both seasons, while the dominant mould was Rhizopus in summer and Monascus in winter, respectively. The diversity of yeasts and moulds in winter was far greater than that in summer, especially in alcoholic fermentation stage. Collectively, our work revealed critical insights into effect of seasonal variation on the structure of microbiota of Shanxi mature vinegar, and was relevant in understanding the relationships between environmental change and microbiota.

Selective adsorption behavior of Cd(II) ion imprinted polymers synthesized by microwave-assisted inverse emulsion polymerization: Adsorption performance and mechanism.

Microwave-assisted inverse emulsion polymerization method was used to prepare Cd(II) imprinted polymer (IIP) by using ß-cyclodextrin (ß-CD) and acrylamide (AM) as functional monomer, epichlorohydrin (ECH) as crossing-linking agent, ammonium persulfate as initiator. The Cd(II) imprinted polymer was characterized by SEM, FTIR and TGA. The influences of initial concentration of Cd(II), pH values, temperature, time and competitive ions on adsorption capacity and recognition properties are investigated. Under the optimal conditions, the adsorption capacity could reach 107mg/g. Furthermore, pseudo first order kinetic model, pseudo second order kinetic model and intra-particular diffusion model were used to describe the adsorption kinetic behavior. Results showed that the pseudo-second-order model (R2 0.9928-0.9961) had the best agreement with the experimental data. Langmuir adsorption isotherm model described the experimental data well, which indicated that adsorption was mainly monolayer absorption. Moreover, the study of adsorption thermodynamics (ΔG0<0, ΔH0>0, ΔS0>0) suggested that the adsorption process was a spontaneous and endothermic process. Competitive selectivity experiment revealed that imprinted polymer could selectively recognize Cd(II). It provides a new idea for removing Cd(II) from aqueous solution.