Characterizing Soy Sauce Moromi Manufactured by High‐Salt Dilute‐State and Low‐Salt Solid‐State Fermentation Using Multiphase Analyzing Methods

Present study was to characterize the physiochemical properties, free amino acids (FAAs), volatiles and microbial communities of various moromi, respectively sampled from different stages of high‐salt dilute‐state (HSDS) and low‐salt solid‐state (LSSS) fermentation, using multiphase analyzing methods. Phospholipid fatty acids (PLFA) analysis indicated that Gram‐positive bacteria were dominant bacteria and fungi were principal microbes. For DGGE analysis, dominant microbes in moromi were mainly fell into Weissella, Tetragenococcus, Candida, Pichia, and Zygosaccharomyces. During fermentation, the dominant microbes shifted from nonhalophilic and less acid‐tolerant species to halophilic and acid‐tolerant species. Total of 15 FAAs and 44 volatiles were identified in moromi, mainly Glu, Asp, Tyr, and acids, alcohols, esters, aldehydes, respectively. Odor activity values analysis suggested that the final moromi of LSSS fermentation had more complicated odors than that of HSDS fermentation. Conclusively, technological parameters, microbial communities, raw materials and fermentation process may result in the discrepancy of HSDS and LSSS moromi.     

低温厌氧氨氧化生物滤池群落结构分析

为了解低温(150～165 ℃)稳定运行的厌氧氨氧化生物滤池微生物特征,利用扫描电镜(SEM)、变性梯度凝胶电泳技术(DGGE)和克隆测序等方法,对低温稳定运行的两个上流式厌氧氨氧化生物滤池进行微生物群落结构分析．SEM结果显示,陶粒填料反应器(B1)内丝状菌较多,球形细菌分布密度较低,而火山岩填料反应器(B2)没有发现丝状菌,球形细菌分布密集．DGGE结果表明,B1与B2反应器微生物种类有所差别,种群相似性为681％,B2反应器内细菌丰度更高,但两反应器内厌氧氨氧化细菌种类相同．通过细菌及ANAMMOX菌16S rRNA克隆测序,鉴定反应器内厌氧氨氧化细菌为Candidatus Kuenenia stuttgartiensis．采用火山岩填料生物滤池反应器形式,并富集Candidatus Kuenenia stuttgartiensis,有助于厌氧氨氧化工艺在较低温度(150～165 ℃)条件下稳定运行和推广应用．     

Comparison of hydrogen-producing bacterial communities adapted in continuous and discontinuous reactors

We evaluate the bacterial composition during the anaerobic granules adaptation for hydrogen production using continuous and discontinuous feeding-regime. Adaptation was induced by employing short hydraulic retention times and low pH. The microbial community analysis revealed that both discontinuous and continuous adaptation strategies resulted in the selection of different microorganisms despite the use of the same initial inoculum. The dominant microorganisms present in the continuous process belong to the genus Escherichia and Clostridium; while in the discontinuous adaptation prevailed Clostridiales. The different feeding-regimes applied not only reduced the diversity, but also the composition of the microbial community. The Jaccard's and Shannon–Wiener indexes showed that the different operational strategies applied not only reduced the diversity, but also the composition of the microbial community.     

PCR-DGGE技术分析浸矿体系细菌群落结构的实验优化

为了研究低品位黄铜矿细菌搅拌浸出的浸矿菌液中的细菌群落结构,对 PCR-DGGE(变性梯度凝胶电泳)技术相关的实验方法进行了优化,主要涉及低丰度基因组 DNA提取方法优化、16SrRNA基因的 PCR扩增条件优化以及变性梯度凝胶电泳条件的优化.结果表明,采用分级离心多次浓缩的方法收集矿浆样品中的菌体,再用试剂盒提取基因组 DNA,有较好效果;使用含特定“GC夹板”的引物5′-CGCCCGCCGCGCCCCGCGCCCGTCCCGCCGCCCCCGCCCG-3′进行热启动降落 PCR,能显著提高目的条带的 PCR扩增效率;当 DGGE电泳设置温度为60℃左右,胶浓度为6%,尿素变性梯度为30%~50%,恒定电压为100V,时间为9h时,可以获得效果较好的 DGGE电泳图谱,该优化方案提高了对浸矿体系中细菌群落结构的检测效果     

Microbiological characterisation of Robiola di Roccaverano cheese using PCR-DGGE

The aim of this study was the microbiological characterisation of a typical Italian cheese “Robiola di Roccaverano” with Protected Designation of Origin (PDO). Fresh and ripened robiola samples were collected from four artisanal and one industrial producer. Artisanal producers used raw goat's milk and natural fermentation, whilst the industrial producer used mixed cow–goat's milk and selected starters. The microbial communities were monitored during different seasons and ripening times with PCR–DGGE and culture-dependent methods.The cluster analysis showed that the DGGE bacterial patterns were related to the different manufacturing and climatic conditions, revealing the occurrence of species associated to Robiola di Roccaverano. The DGGE profiles of yeasts were affected by ripening in summer season.Moreover, the results obtained allowed the identification of microbial species such as Lactococcus lactis subsp. lactis, Geotricum spp. and Kluyveromyces lactis that are related to the production of this typical cheese.     

水杨酸铬(Ⅲ)配合物对肥胖小鼠肠道菌群的影响

目的探讨水杨酸铬(Ⅲ)配合物{[Cr(Ⅲ)(5-Cl-SA)(en)2]Cl·2H2O·2CH3OH}对肥胖小鼠的减肥效果和对小鼠肠道菌群结构的影响。方法昆明种小鼠随机分为正常组、模型组和药物组,定期称重并收集其粪便;给药9周后,解剖小鼠并测定多项生理生化指标;提取粪便微生物总DNA,PCR扩增16S rDNA V3可变区,并行变性梯度凝胶电泳(DGGE),分析肠道微生物多样性,利用主成分分析(PCA)研究肠道微生物群落组成的变化。结果水杨酸铬(Ⅲ)配合物可显著控制小鼠体重增长,且有减肥功效;给药9周后,小鼠各项生理指标均趋于正常。PCR-DGGE指纹图谱分析结果显示,高脂饲料和受试药物对肠道微生物的多样性影响不大,但对菌群结构影响显著。结论本研究为开发新型减肥药物提供了依据。     

大鼠粪便中细菌基因组DNA提取方法的比较

为获得高质量的肠道细菌基因组DNA,用于研究肠道菌群的多样性,本实验分别采用改良的溶菌酶法和两种试剂盒DNA提取法提取大鼠粪便中的细菌基因组DNA,通过DNA浓度和纯度的测定、PCR-变性梯度凝胶电泳技术（PCR-DGGE技术）对提取效果进行比较,以找到适合于粪便中细菌基因组DNA的提取方法。结果表明,改良的溶菌酶法提取的DNA质量好,纯度高,而且具有菌群多样性丰富等特点,更适合用于肠道微生物菌群后续分子生物学研究。      

Microbiological Analyses of Dry and Slurry Yeasts for Brewing

Classical microbiological methods in association with molecular methods (DNA amplification, Temperature Gradient Gel Electrophoresis (TGGE) and Denaturing Gradient Gel Electrophoresis (DGGE) were used. These methods, developed to rapidly analyze microbial communities on the basis of sequence‐specific separation of DNA amplicons, allowed the detection of DNA differences in the amplicons tested and the identification of the strains analyzed by the comparison of unknown sequences with sequences of known species. TGGE allowed the comparison of the different Saccharomyces cerevisiae strains used in brewing while DGGE allowed the identification of lactic acid bacteria (LAB) in beer. These methods are a reliable tool for fast comparison of strains of Saccharomyces cerevisiae collected from different craft breweries where they were used as starters to check the presence of possible yeast contaminants in the brewing process and for rapid LAB identification.