Analysis of bacterial communities in pit mud from Zhijiang Baijiu distillery using denaturing gradient gel electrophoresis and high- throughput sequencing

Zhijiang Baijiu is a Chinese strong flavour liquor produced using a traditional Chinese solid state fermentation involving microorganisms in pit mud on cellar walls. In this study, pit mud samples were collected from three different cellars in a Zhijiang Baijiu distillery ranging in age from 10 to 20 and 30 years. The bacterial communities were analysed using denaturing gradient gel electrophoresis, high-throughput sequencing and quantitative real time PCR. These analyses showed that the diversity of the bacterial community in pit mud samples was relatively stable in cellars aged from 20 to 30 years old. High throughput sequencing also revealed that the relative abundance of seven core bacterial families and nearly half of the core bacterial genera were stable in 20 year-old cellars. In cellars of 10 to 30 years, the relative abundance in pit mud of Ruminococcaceae and Clostridium cluster IV increased, while that of Petrimonas and an unclassified Firmicutes decreased. Real time PCR showed that aged pit mud contained more bacteria and Clostridium kluyveri than young pit mud. It is concluded that the bacterial communities in aged pit mud are more suitable for producing high quality Baijiu. © 2019 The Institute of Brewing & Distilling     

A/A/MBBR工艺处理混合污水的脱氮除磷中试研究

采用A/A/MBBR工艺处理由粪便液和生活污水组成的混合污水,试验条件:填料投配比为20%,好氧池1和好氧池2中的填料体积比为1:3,好氧池的水力停留时间为5 h,混合液回流比为120%,污泥回流比为60%,泥龄为6 d,好氧池的溶解氧为3.0 mg/L,温度为16～20℃.系统稳定运行一个月的结果表明:脱氮除磷效果及对有机物的去除效果均稳定而良好,出水氨氮、总氮、总磷和COD平均浓度分别为0.3、12.9、0.35和36.22 mg/L,均达到了国家一级A排放标准.     

解体好氧颗粒污泥强化修复及其微生物群落演替特征

通过在解体的好氧颗粒污泥中投加硫酸铝来强化颗粒的再形成过程,并对期间微生物的群落演替特征进行了分析。结果表明,硫酸铝的投加加速了解体颗粒污泥的再形成,并且再形成的颗粒污泥具有更加良好的污泥特性和更高的细菌总数。在强化修复过程中,颗粒污泥中的优势菌群主要分布于变形菌门(Proteobacteria),其中假单胞菌(Pseudomonas)是Proteobacteria中的主要菌属。     

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     

Effect of carbendazim and pencycuron on soil bacterial community

Soil bacterial composition is used as one of the important indicators of negative effects of the use of pesticides in agriculture. Very little is known on the effects of fungicides, particularly carbendazim and pencycuron on soil bacterial community. In this study, laboratory experiments were conducted to examine the effects of various concentrations of carbendazim and pencycuron on diversity of bacterial community in soils collected from strawberry field and incubated at different temperature conditions. The degradation rate of fungicides both in sterile and non-sterile soils were also investigated. Residues of fungicides were measured using high performance liquid chromatography (HPLC) and the change in bacterial community was examined by comparing the 16S rDNA bands on patterns by denaturing gradient gel electrophoresis (DGGE). The dissipation of carbendazim was affected by concentration applied, whereas that of pencycuron was affected by both concentration applied and incubation temperature. The microbial community could recover to its previous composition after 126 days of cultivation with the application of 10 mg/kg of carbendazim but not with the application of a high concentration, 100 mg/kg, of pencycuron. From cluster analysis, the bacterial community structure showed approximately 50% similarity throughout the experimental period, which indicated that the soil microbiota composition was not stable throughout the 120 cultivation days.     

Comparison of planktonic and reed biofilm bacteria in different riverine water bodies of river Danube

As the submerged shoot parts of common reed (Phragmites australis) can provide large surfaces for biofilm‐forming bacteria, extensive reed stands can effectively contribute to the self‐purification in the littoral zones of freshwaters. However, bacterial biofilm developed on reed surfaces have been studied only in still waters. In the present study, comparative examinations were performed on the planktonic and reed biofilm bacterial communities from two different riverine water bodies. Water and reed biofilm samples were taken at the beginning and end of the vegetation period from (a) a regulated side arm and (b) a separated oxbow of River Danube. Besides measuring physical and chemical environmental variables, planktonic bacterial cell numbers were detected by 4′,6‐diamidino‐2‐phenylindole staining method, and the bacterial communities were compared by denaturing gradient gel electrophoresis. Our results demonstrated that the structure and composition of bacterial communities correlated with different environmental variables and were different regarding both the habitats (planktonic vs. reed biofilm) and the types of riverine water bodies. The seasonal differences in the bacterial community structures were smaller in the river side arm than in the separated oxbow. In the water column, representatives of widespread and typical freshwater planktonic bacteria (“Candidatus Planktophila,” Limnohabitans, and Polynucleobacter), whereas, in the reed biofilm samples, phototrophic and plant associated bacteria were identified.     

PLFA法和DGGE法分析制曲过程微生物群落变化

同时采用PLFA(Phospholipid fatty acid)谱图分析法和DGGE(Denaturing gradient gel electrophoresis)法分析大曲制曲过程中微生物群落的变化.结果表明:真菌类微生物生物量呈现先下降后上升趋势,发酵第7天各种微生物含量达到极限值,随后呈下降的趋势.通过贮存期...     

Effect of mobilizing agents on mycoremediation and impact on the indigenous microbiota

BACKGROUND: Mobilizing agents (MAs) have been suggested to improve the fungal degradation of polycyclic aromatic hydrocarbons (PAHs) in soil. Three different MAs (Tween 20, Tween 80 and soybean oil) were investigated for their ability to stimulate contaminant degradation by either Phlebia sp. DABAC 9 or Allescheriella sp. DABAC1 in a soil spiked with a mixture of PAHs. RESULTS: Phlebia sp. and Allescheriella sp. markedly differed in their growth capabilities under non‐sterile conditions and without MAs (3.0 versus 0.1 µg ergosterol g^?1 soil, respectively). However, soybean oil led to a 35‐fold increase of Allescheriella sp. growth. Contaminant degradations by Phlebia sp. DABAC 9 and Allescheriella sp. DABAC 1 were best supported by soybean oil and Tween 20, respectively. Enumeration of cultivable bacteria and denaturing gradient gel electrophoresis (DGGE) analysis of PCR‐amplified 16S rRNA showed that microbial density and biodiversity were positively affected by the mycoremediation especially with Allescheriella sp., the use of which led to an evident detoxification. CONCLUSIONS: Allescheriella sp. DABAC 1 appears to be a promising strain in the remediation of PAH‐contaminated soils. The different response of the two fungi to MAs addition confirms the stringent need for a preliminary lab‐scale assessment of fungus/MA combinations prior to application. Copyright © 2009 Society of Chemical Industry     

Effect of grazing intensities on the activity and community structure of methane-oxidizing bacteria of grassland soil in Inner Mongolia

The effects of different grazing intensities on in situ methane flux and the structure and diversity of the methanotrophic community are measured in the typical grassland of Inner Mongolia. Four grazing intensity sites founded in 1989, control (CK), low-intensity grazing (LG), middle-intensity grazing (MG) and heavy-intensity grazing (HG), were selected. Group-specific PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) of 16S rRNA genes for the type I and type II methanotrophs was used to characterize the composition of the methanotrophic community. DGGE patterns were further analyzed using the method of the Shannon-wiener index H and non-metric multi-dimensional scaling (MDS). The results showed that there were no significant differences in methane flux among different sites, yet methanotrophic communities showed significant differences. MDS analysis showed that type I methanotroph community composition at the CK site were significantly different from the three other sites. For type II methanotrophic community composition, it was similar between CK and HG site, and between LG and MG site, while that at the former two sites were significantly different from latter two ones. Additionally Shannon indices of type II methanotrophs were higher at the LG and MG sites than two other sites. Though grazing intensities had an impact on the structure of the methanotrophic community, management-induced changes in the structure of methanotrophic community did not reflect methane consumption capacity across sites. These results suggest that methane consumption is a complex process in soil, and we should be cautious when speculating on the change of methane consumption rates based on a change of methanotrophic community structure.     

Molecular Identification of Microbial Community in Surface and Undersurface Douchi During Postfermentation

To find the reason for fermentation failure of surface Douchi during postfermentation, the microbial communities in undersurface and surface samples were investigated using cell counting method and denaturing gradient gel electrophoresis (DGGE). The results showed that the microbial biomass in surface Douchi was obviously different from that in undersurface Douchi even sampled from the same fermentation tanks, and a 10‐ to 100‐fold reduction of microbial cell counts in undersurface had been observed. The bacterial DGGE profile and principal component analysis (PCA) results indicated that only Lactococcus lacts subsp. lactis and Bacillus thermoamylovorans were detected from surface Douchi, while Lactococcus lacts subsp. lactis, Staphylococcus lentus and 2 uncultured strains occupied the dominant positions in undersurface Douchi; when amplified using Bacillus‐specific primers, Bacillus thermoamylovorans, Bacillus subtilis, and Enterobacter sp. were found in undersurface Douchi, while only Bacillus thermoamylovorans were detected from surface Douchi; compared to the bacteria and Bacillus, the DGGE profiles and PCA plot of fungi indicated that the fungal community between surface and undersurface Douchi was similar and mainly composed by yeasts. In this study, we detected the microbial biomass and species in postfermentation stage of Douchi, and the various microbial diversity in undersurface and surface samples might be the cause of the fermentation failure in surface fermentation tanks.