Determination of the archaeal and bacterial communities in two-phase and single-stage anaerobic systems by 454 pyrosequencing

2-Phase anaerobic digestion (AD), where the acidogenic phase was operated at 2 day hydraulic retention time (HRT) and the methanogenic phase at 10 days HRT, had been evaluated to determine if it could provide higher organic reduction and methane production than the conventional single-stage AD (also operated at 12 days HRT). 454 pyrosequencing was performed to determine and compare the microbial communities. The acidogenic reactor of the 2-phase system yielded a unique bacterial community of the lowest richness and diversity, while bacterial profiles of the methanogenic reactor closely followed the single-stage reactor. All reactors were predominated by hydrogenotrophic methanogens, mainly Methanolinea. Unusually, the acidogenic reactor contributed up to 24% of total methane production in the 2-phase system. This could be explained by the presence of Methanosarcina and Methanobrevibacter, and their activities could also help regulate reactor alkalinity during high loading conditions through carbon dioxide production. The enrichment of hydrolytic and acidogenic Porphyromonadaceae, Prevotellaceae, Ruminococcaceae and unclassified Bacteroidetes in the acidogenic reactor would have contributed to the improved sludge volatile solids degradation, and ultimately the overall 2-phase system''s performance. Syntrophic acetogenic microorganisms were absent in the acidogenic reactor but present in the downstream methanogenic reactor, indicating the retention of various metabolic pathways also found in a single-stage system. The determination of key microorganisms further expands our understanding of the complex biological functions in AD process.     

Performance and microbial diversity of an expanded granular sludge bed reactor for high sulfate and nitrate waste brine treatment

The disposal of waste brines has become a major challenge that hinders the wide application of ion- exchange resins in the water industry in recent decades. In this study, high sulfate removal efficiency （80%-90%） was achieved at the influent sulfate concentration of 3600 mg/L and 3% NaC1 after 145 days in an expanded granular sludge bed （EGSB） reactor. Furthermore, the feasibility of treating synthetic waste brine containing high levels of sulfate and nitrate was investigated in a single EGSB reactor during an operation period of 261 days. The highest nitrate and sulfate loading rate reached 6.38 and 5.78 kg/（m3-day） at SO42--S/NO3-N mass ratio of 4/3, and the corresponding removal efficiency was 99.97% and 82.26% at 3% NaC1, respectively. Meanwhile, 454-pyrosequencing technology was used to analyze the bacterial diversity of the sludge on the 240th day for stable operation of phase X. Results showed that a total of 9194 sequences were obtained, which could be affiliated to 14 phyla, including Proteobacteria, Firmicutes, Chlorobi, Bacteroidetes, Synergistetes and so on. Proteobacteria （77.66%） was the dominant microbial population, followed by Firmicutes （12.23%） and Chlorobi （2.71%）.     

城市污水管网中产甲烷菌的分布特性规律

实验通过一套1 200 m的PVC管式反应器来模拟城市污水管网,利用气相色谱法、液相色谱法和454高通量测序等手段,研究了城市污水管网中产甲烷过程中的物质变化和产甲烷菌分布特性规律.结果表明,管网中甲烷含量沿程升高,说明管网中存在产甲烷菌;产甲烷菌主要包含甲烷八叠球菌属(Methanosarcina)、广古菌门中的菌属(Euryarchaeota_unclassified)和甲烷杆菌科中的菌属(Methanobacteriaceae_unclassified)这3种优势菌属,且在管网800~1 000 m处有广古菌门中的菌属(Euryarchaeota_unclassified)取代甲烷八叠球菌属(Methanosarcina)成为第一优势菌属的演替现象;管网中产甲烷可利用基质有甲酸、甲醇、甲胺、乙酸,其中乙酸为主要基质,这些基质在管网中先增加后降低的变化趋势导致了管网中产甲烷菌演替现象的发生.     

Effects of river sediment addition to the beach microbial communities

During the processes of claiming land from the sea, river sediments are used to fill and transform the sea area along the margin of islands and lands into new lands. These activities would probably affect microbial ecosystems of the beach sediment. However, little is known about these effects. In this study, a simulation test was conducted to evaluate these effects. Pyrosequencing technique was employed to assess the effects of river sediment addition to the beach bacterial communities. The used river sediments were collected from different rivers. The results indicated that river sediment addition greatly impacted microbial ecosystems of the beach and caused a clear shift in the beach bacterial community composition. These processes remarkably increased toxic metals and decreased the bacterial diversity in the beach sediment, mainly including the phyla of Bacteroidetes, Cyanobacteria, Proteobacteria, and Spirochaetes. River sediment addition caused an increase in potentially pathogenic bacterial genera of the beach sediment. Bacterial phylotype richness in the beach without river sediment addition was higher than that in the beach with river sediment input. There were significant differences in bacterial communities between beach sediments with and without river sediment addition, and the most dominant classes were Gammaproteobacteria and Flavobacteria.     

Metagenomic assessment of the microbial diversity in ground pork products from markets in the North Central Region of South Korea

The purpose of this study was to characterize the microbial community in ground pork using molecular approaches. Forty six ground pork products were purchased from local stores in the north central area of South Korea. Aerobic plate counts varied 4.23 ± 5.14 × 10⁵ CFU/g with the range between 5.00 × 10³ and 1.85 × 10⁶ CFU/g for ground pork samples. Four ground meat samples were further processed for metagenomic analysis. Pseudomonas species was the most relative abundant with a wide range occurring (1.72 to 77.7%) as part of the microbial genera in ground pork. Bacteria such as Carnobacterium, Yersinia, Photobacterium were also identified in ground pork. Despite the prominence of certain genera across all samples there was still extensive microbial diversity among ground pork products that originated from different slaughter houses and were processed in different markets. Such diversity indicates that designing interventions to extend shelf life may be hampered by the extensive variability in the microbial consortia associated with pork products. However, this diversity may be useful for developing microbial traceability signatures unique to a slaughter house or a particular market.     

454焦磷酸测序技术分析A+OSA污泥减量工艺真核生物特征

以缺氧-好氧(AO)工艺为参照,利用454焦磷酸测序技术研究了缺氧-好氧-沉淀-厌氧(A+ OSA)污泥减量工艺真核生物分布特征.实验结果表明,A+ OSA污泥减量工艺真核生物丰富度与多样性均低于AO参照工艺,两工艺主要真核生物门为环节动物门Annelida,纤毛虫门Intramacronucleata和SAR超类群(不等鞭毛生物Stramenopiles,囊泡虫Alveolates,有孔虫Rhizaria),Annelida及SAR相对含量在减量工艺中明显减低.纲水平分类结果表明,前口纲Prostomatea在减量工艺中消失,寡膜纲Oligohymenophorea在减量工艺贮泥池中成为优势真核生物.A+OSA污泥减量工艺贮泥池中选择性富集真核生物Oligohymenophorea表明微型生物捕食作用存在该工艺中,对减量工艺的污泥减量具有贡献.     

焦化废水活性污泥中降解硫氰化物细菌种群多样性分析

硫氰化物(SCN-)是焦化废水中COD的主要来源之一,其在生物处理工艺好氧段的去除效果直接影响出水的达标排放,活性污泥中的微生物种群在SCN-生物处理中发挥重要作用.以SCN-为唯一碳源和能源驯化活性污泥,研究其对100、300和600 mg·L-1SCN-浓度的去除降解效果,并利用454测序技术解析污泥中降解SCN-的细菌多样性.结果表明,驯化污泥能有效去除100~600 mg·L-1SCN-,SCN-浓度越高,去除速率越高,然而细菌群落多样指数越低;原始污泥和驯化污泥的细菌门类群主要为Proteobacteria、Bacteroidetes、Chlorobi、Planctomycetes、Acidobacteria、Nitrospira、Firmicutes和Unclassified,其中Proteobacteria和Bacteroidetes门占主导地位;Thiobacillus是主要的SCN-降解菌,在3个污泥样品中的丰度分别为3.07%、8.63%和0.27%.Thiobacillus是浓度小于300 mg·L-1SCN-时焦化废水中主要的SCN-降解菌,而在600 mg·L~(-1) SCN-高浓度时低丰度的SCN-降解菌群可能发挥协同降解作用.这些结果为揭示焦化废水处理SCN-污染物的去除机制提供了基础.     

滆湖底泥细菌群落结构及多样性

2015年11月中旬采集常州滆湖底泥及水样,在滆湖水体及底泥现状分析的基础上,采用高通量测序技术对底泥细菌的16S rRNA基因进行序列测定,对底泥细菌群落结构及多样性进行研究.结果显示:滆湖水质整体呈富营养化状态,殷村港、湖北区为轻度富营养化,繁保区、塘门沟为中度富营养化.底泥细菌测得总OTUs(Operational Taxonomic Units)数为6157,多样性高.滆湖底泥细菌隶属26门38纲141属,其中以Proteobacteria、Chloroflexi、Deltaproteobacteria、Betaproteobacteria和Deltaproteobacteriawei为主,并含有少量丰度的Planctomycetacia、Alphaproteobacteria、Thiobacillus、Polynucleobacter和Geobacter等.研究发现,Firmicutes和Alphaproteobacteria丰度与富营养化指数呈显著正相关,而Betaproteobacteria、Actinobacteria和Bacteroidetes丰度与富营养化指数呈显著负相关,即富营养化程度越高,Firmicutes和Alphaproteobacteria丰度也越大,Betaproteobacteria、Bacteroidete和Actinobacterias丰度则越小.     

水源切换对水厂出水细菌群落的影响

针对水源切换可能造成水厂出水微生物风险的问题,以北京某水厂由本地水源切换为河北水源期间原水和出厂水为研究对象,采用焦磷酸测序技术对水中的微生物种群结构和潜在致病菌进行分析.结果显示,出厂水的细菌多样性显著低于原水,原水和出厂水中的优势菌均为变形菌门(Proteobacteria),所占比例为11.99%~95.48%,其中包括α,β和γ变形菌纲(α, β, γ-Proteobacteria),但相对丰度有较大差异.水源切换后的原水中优势菌为蓝藻门(Cyanobacteria),且该菌在切换后的出厂水中也存在.出厂水中检测到部分潜在致病菌,优势菌包括不动杆菌(Acinetobacter)和代尔夫特菌(Delftia),增加了饮用水的微生物安全风险.PCoA结果显示,水源切换前后原水中细菌群落结构变化较大,但改变水源对出厂水的微生物群落影响较小,水厂能够维持稳定的运行.     

印染废水接触氧化池中悬浮污泥和生物膜的微生物群落比较分析

为了揭示接触氧化池中悬浮污泥和生物膜菌群群落结构的异同,提取基因组DNA,采用PCR扩增与454高通量测序技术对两者菌群测序并进行了操作单元(OTU)聚类分析、多样性分析和分类学分析。结果表明,悬浮污泥和生物膜菌群的高通量测序分析分别得到优化序列8 256条和10 592条,测序覆盖深度都在80%左右,经过97%相似度归并后分别得到570个OTUs和694个OTUs,菌群多样性分析显示悬浮污泥内菌群的丰度和多样性都低于生物膜,悬浮污泥有356个属的细菌构成,而生物膜内则有387个,都归属于21个门。悬浮污泥和生物膜内不仅存在共有菌种,也含有各自的特定菌种,说明不同的微环境使其有了相对应的优势群落。通过这种差异的比较分析,更能准确地了解接触氧化池中微生物的群落组成情况,有利于分析其与系统功能的关系。