好氧活性污泥中的产甲烷菌

通过最可能数(MPN)计数试验,发现在四种好氧活性污泥中存在产甲烷菌,数量在10~3—10~9/gVSS,其中有利用H_2/CO_2的氢营养型产甲烷菌和既能利用乙酸盐、又能利用H_2/CO_2的混合营养型产甲烷菌,可能还有利用乙酸盐的乙酸盐营养型产甲烷菌。活性污泥中存在产甲烷菌可能与污泥絮体内存在厌氧核心和某些产甲烷菌的耐氧性有关。     

ABR启动期运行效能及互营产甲烷菌群的分布特征

为探讨厌氧折流板反应器（ABR）启动期运行效能和互营产甲烷菌群的空间分布特征,考察了ABR反应器处理制糖废水启动期的运行特征,并采用聚合酶链式反应-变性梯度凝胶电泳（PCR-DGGE）技术分析了互营产甲烷菌群在ABR各格室的分布规律.结果表明,在污泥驯化阶段,ABR的COD去除率为61.5%,出水挥发酸总量高达1808mg/L.经过2个阶段的调控运行后,ABR出水挥发酸明显降低,甲烷含量增加至55%以上,COD去除率达到了94.8%.而且ABR第2~4格室形成了沉降性能良好的颗粒污泥.PCR-DGGE检测结果表明,该ABR系统中的主要产氢产乙酸菌为Syntrophobacter和Pelotomaculum,主要分布在ABR系统第3,4格室.ABR第1,2格室的产甲烷菌主要为耐酸的氢营养型产甲烷菌（Methanoregula和Methanosphaerula）,而乙酸营养型产甲烷菌（Methanosaeta和Methanothrix）主要分布在第3,4格室.ABR系统中产甲烷菌的多样性要明显高于产氢产乙酸菌,说明当系统受到冲击时,产氢产乙酸作用比产甲烷作用更易成为限速步骤.     

qPCR揭示丙酸降解菌群随OLR提高的演替规律

为探讨有机负荷率（OLR）对升流式厌氧污泥床（UASB）反应器运行效能的影响及互营丙酸降解菌群的响应,以稀释的制糖废水为底物,考察了OLR升高对UASB处理效能的影响,并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群随OLR提高的演替规律.结果表明,在OLR为6.0~54.0kgCOD/（m³·d）的范围内,UASB处理制糖废水取得了良好的效果,其COD去除率为92.0%以上.qPCR检测结果表明,至少有3种已鉴定的丙酸氧化菌（Pelotomaculum schinkii,P.propionicum和Syntrophobacter sulfatireducens）存在于UASB反应器中.其中,S.sulfatireducens是主要的丙酸氧化菌,其数量为126~1.2×10³ 16S rRNA基因拷贝数/ng DNA,约占检测到丙酸氧化菌总数的47.9%~58.6%.OLR从6.0提高至54.0kgCOD/（m³·d）导致所有丙酸氧化菌数量显著减少.Methanospirillum hungatei和Methanosaeta concilii是该UASB系统中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌.与丙酸氧化菌的变化趋势相反,这两种产甲烷菌的数量均随OLR的提高而显著增加,并在OLR54.0kgCOD/（m³·d）条件下达到最大值.     

海洋油气田沉积物产甲烷活性及微生物生态

海洋产甲烷古菌是与海洋中甲烷的产生、释放及天然气水合物的形成等密切相关的微生物类群.以产甲烷菌可能利用的底物为碳源,评价了海洋油气田沉积物的产甲烷活性.结果表明,海洋油气田沉积物对于H2/CO2、甲醇、一甲胺、三甲胺,在25℃和37℃两种温度条件下都具有较高的产甲烷活性,少数样品只在37℃对乙酸有产甲烷活性,说明在海洋油气田环境下,主要有氢营养型及甲基营养型发酵途径产生天然气甲烷.利用厌氧培养法对产甲烷菌进行了多样性解析,16S rRNA基因测序显示,优势产甲烷菌主要属于Methanosarcinales目的 Methanosarcinaceae科及Methanomicrobiales目的 Methanomicrobiaceae科,其中Methanococcoides、Methanogenium和Methanosarcina为油气田沉积物的主要菌属.     

Methanogene Bakterien

Methanogenic bacteria area diverse group of anaerobic procaryotes that ferment CO₂ plus H₂ to CH₄. Besides their unusual energy metabolism they are unique in that their cell walls do not contain murein, and in that their cell membranes are composed of isoprenoid lipids. Coenzymes occur which are not found in any other living organism. The translation apparatus differs, e.g., in not being affected by antibiotics known to be inhibitors of procaryotic protein synthesis. Most of the methanogens can grow on CO₂ as sole carbon source; autotrophic CO₂ fixation does not, however, proceed via reactions of the Calvin cycle. Molecular genealogical analysis has revealed that methanogenic bacteria constitute a grouping phylogenetically distinct from most other procaryotes.     

Microbial community structures in an integrated two-phase anaerobic bioreactor fed by fruit vegetable wastes and wheat straw

The microbial community structures in an integrated two-phase anaerobic reactor（ITPAR）were investigated by 16 S r DNA clone library technology. The 75 L reactor was designed with a 25 L rotating acidogenic unit at the top and a 50 L conventional upflow methanogenic unit at the bottom, with a recirculation connected to the two units. The reactor had been operated for 21 stages to co-digest fruit/vegetable wastes and wheat straw, which showed a very good biogas production and decomposition of cellulosic materials. The results showed that many kinds of cellulose and glycan decomposition bacteria related with Bacteroidales,Clostridiales and Syntrophobacterales were dominated in the reactor, with more bacteria community diversities in the acidogenic unit. The methanogens were mostly related with Methanosaeta, Methanosarcina, Methanoculleus, Methanospirillum and Methanobacterium; the predominating genus Methanosaeta, accounting for 40.5%, 54.2%, 73.6% and 78.7% in four samples from top to bottom, indicated a major methanogenesis pathway by acetoclastic methanogenesis in the methanogenic unit. The beta diversity indexes illustrated a more similar distribution of bacterial communities than that of methanogens between acidogenic unit and methanogenic unit. The differentiation of methanogenic community composition in two phases, as well as pH values and volatile fatty acid（VFA） concentrations confirmed the phase separation of the ITPAR. Overall, the results of this study demonstrated that the special designing of ITPAR maintained a sufficient number of methanogens, more diverse communities and stronger syntrophic associations among microorganisms, which made two phase anaerobic digestion of cellulosic materials more efficient.     

乙酸驯化对厌氧污泥微生物群落结构及发酵特性的影响

采用乙酸对厌氧污泥进行逐步驯化,以富集乙酸营养型产甲烷菌群,解决厌氧发酵过程中的酸抑制问题.对驯化前后污泥中的微生物群落结构及其在高酸浓度和低p H值条件下的发酵特性进行了研究.结果表明:驯化后污泥中乙酸营养型产甲烷菌中的甲烷八叠球菌属(Methanosarcina)得到了明显富集,其相对丰度由原始的4.2%提高到58.1%,成为耐酸污泥中的主导优势古菌群;氢营养型产甲烷菌属的丰度则都有不同程度的下降.污泥中产甲烷菌群由氢营养型为主导转为乙酸营养型和氢营养型共同主导.驯化前后污泥中细菌的优势菌门均为主要降解纤维素和半纤维素的厚壁菌门(Firmicutes)和降解蛋白质的拟杆菌门(Bacteroidetes),其中驯化后Firmicutes的丰度由48.8%提高到61.7%,而Bacteroidetes的丰度则由30.1%降低至16.9%.驯化后的污泥对高VFA浓度和低pH值的耐受性均有较大程度的提高,其在VFA浓度为7500 mg·L~(-1)及pH 6.0条件下仍可以快速产气.     

PCR-DGGE研究青海农村户用沼气池微生物群落结构

采用变性梯度凝胶电泳(DGGE)分析技术,对青海农村户用沼气池内细菌及古菌群落结构进行分析.结果表明,沼气池含有丰富的细菌及古菌类群,且泥样间的细菌和古菌的群落结构存在差异.4个户用沼气池发酵系统中,细菌分属于5个门,优势类群为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria).在属分类水平上,属于24个类群,最优势类群为理研菌科佩特里单胞菌属(Petrimonas)、假单胞菌属(Pseudomona)、泰氏菌属(Tissierella)和梭菌属(Clostridium).同时,沼气池发酵系统中古菌主要包括热丝菌属(Thermofilum)、甲烷短杆菌属(Methanobrevibacter)、甲烷囊菌属(Methanoculleus)、产甲烷菌属(Methanogenium),其中,Methanobrevibacter和Methanogenium是沼气池内最优势的产甲烷菌.说明沼气池的产甲烷途径主要是氢营养代谢类型,水解、酸化过程主要由来自动物消化系统内的细菌完成.     

厨余垃圾厌氧发酵失稳调控及微生物群落分析

针对厨余垃圾厌氧发酵过程中容易积累丙酸和丁酸导致反应体系酸化失稳的问题,驯化了富集耐丙酸和耐丁酸厌氧发酵菌群的接种菌泥,探究利用其对厨余垃圾干式厌氧发酵酸化失稳体系进行调控后对甲烷产量和微生物群落的影响.酸化失稳厌氧体系中添加耐丙酸菌泥调控后,与空白对照组相比反应体系中丙酸浓度削减6900.81mg/L,累积甲烷产量提...     

UASB启动运行特征及互营丙酸氧化菌定量分析

为揭示升流式厌氧污泥床（UASB）反应器启动运行效能与互营丙酸降解菌群数量之间的关系,以稀释的玉米淀粉生产废水为底物,考察了UASB启动期的运行特征,并采用实时荧光定量PCR技术（qPCR）分析了互营丙酸降解菌群（丙酸氧化菌和产甲烷菌）的演替规律.结果表明,在进水COD 2000mg/L和水力停留时间（HRT）24h条件下,经过38d的连续运行,COD去除率达到了91.9%.当HRT分阶段缩短至8h时,比产甲烷速率达到了315LCH₄/（kg COD·d）,且形成了沉降性能良好的颗粒污泥.qPCR检测结果表明,至少有5种已鉴定的丙酸氧化菌存在于UASB反应器中.Pelotomaculum propionicum为接种污泥中的主要丙酸氧化菌,约占检测到丙酸氧化菌总数的45.7%.它的数量随着HRT缩短不断减少.而Syntrophobacter sulfatireducens和S.wolinii的数量随着HRT缩短不断增加,并在启动完成时达到最大值,分别为1.3×10³,5.5×10³个16S rRNA基因拷贝数/ng DNA,演替成为成熟颗粒污泥中的优势丙酸氧化菌群.Methanobacterium和Methanosarcina为接种污泥中的主要氢营养型产甲烷菌和乙酸营养型产甲烷菌,其数量随着HRT的缩短而逐渐减少,而Methanospirillum和Methanosaeta的数量随HRT的缩短逐渐增加,成为成熟颗粒污泥中的优势产甲烷菌群.     

产甲烷微生物研究概况

甲烷是仅次于CO2的第二大温室气体,因此环境中甲烷来源的研究在环境保护方面具有重要意义.大气中甲烷的浓度(体积分数)约为1.7×10-6,其中约有75%来源于产甲烷菌的代谢.产甲烷菌是一类厌氧古生菌,其分类主要依据为16S rRNA以及其他生化指标.产甲烷菌主要以乙酸、H2和CO2及甲基类化合物为底物并以甲烷为终产物.产甲烷菌生命活动过程深受自然环境的影响.本文从产甲烷菌的发现、形态、分类、代谢机制、生态学研究方面介绍产甲烷菌的研究概况.     

An advanced anaerobic biofilter with effluent recirculation for phenol removal and methane production in treatment of coal gasification wastewater

An advanced anaerobic biofilter (AF) was introduced for the treatment of coal gasification wastewater (CGW), and effluent recirculation was adopted to enhance phenol removal and methane production. The results indicated that AF was reliable in treating diluted CGW, while its efficiency and stability were seriously reduced when directly treating raw CGW. However, its performance could be greatly enhanced by effluent recirculation. Under optimal effluent recirculation of 0.5 to the influent, concentrations of chemical oxygen demand (COD) and total phenol in the effluent could reach as low as 234.0 and 14.2 mg/L, respectively. Also, the rate of methane production reached 169.0 mL CH₄/L/day. Though CGW seemed to restrain the growth of anaerobic microorganisms, especially methanogens, the inhibition was temporary and reversible, and anaerobic bacteria presented strong tolerance. The activities of methanogens cultivated in CGW could quickly recover on feeding with glucose wastewater (GW). However, the adaptability of anaerobic bacteria to the CGW was very poor and the activity of methanogens could not be improved by long-term domestication. By analysis using the Haldane model, it was further confirmed that high effluent recirculation could result in high activity for hydrolytic bacteria and substrate affinity for toxic matters, but only suitable effluent recirculation could result in high methanogenic activity.     

污水处理系统中硝化菌的菌群结构和动态变化

研究分析了4种不同工艺类型的城市污水处理厂中氨氧化细菌(AOB)和亚硝酸盐氧化细菌(NOB)的丰度及菌群结构.实时定量PCR结果表明4种工艺中AOB菌群的丰度范围为8.56×106~4.46×107cells/gMLSS;NOB菌群的丰度为3.37×108~1.53×109cells/gMLSS.每个工艺中Nitrospira都是优势NOB,占NOB菌群的88% 以上. A2O工艺冬季AOB和Nitrospira丰度比夏季均有所降低,这是导致冬季生物脱氮效果变差的主要原因.基于 amoA基因的系统发育分析结果显示所有的序列属于Nitrosomonas,其中Nitrosomonas oligotropha cluster 占克隆文库的60.1%,是AOB 种群中的优势菌属,Nitrosomonas-like cluster和 Nitrosomonas europaea cluster次之,分别占克隆文库的29.6%和9.1%.N. europaea cluster只在A2O工艺中出现,且在A2O工艺夏季污泥样品克隆文库中达到44.7%.低DO运行使N. europaea cluster成为优势AOB是A2O工艺夏季出现较高亚硝酸盐积累率的主要原因.研究结果证实了城市污水处理厂中优势AOB和NOB分别为Nitrosomonas和Nitrospira,硝化菌群占总菌群的1%~7%,其丰度、相对含量和菌群结构是影响硝化效果的主要因素.     

Eubacteria and Archaea community of simultaneous methanogenesis and denitrification granular sludge

Based on the successful performance of a lab-scale upflow anaerobic sludge blanket (UASB) reactor with the capacity of simultaneous methanogenesis and denitrification (SMD), the specific phylogenetic groups and community structure of microbes in the SMD granule in the UASB reactor were investigated by the construction of the Eubacteria and Archaea 16S rDNA clone libraries, fragment length polymorphism, and sequence blast. Real time quantitative-polymerase chain reaction (RTQ-PCR) technique was used to quantify the contents of Eubacteria and Archaea in the SMD granule. The contents of some special predominant methanogens were also investigated. The results indicated that the Methanosaeta and Methanobacteria were the predominant methanogens in all Archaea in the SMD granule, with contents of 71. 59% and 22. 73% in all 88 random Archaea clones, respectively. The diversity of Eubacteria was much more complex than that of Archaea. The low GC positive gram bacteria and Б-Protebacteria were the main predominant Eubacteria species in SMD granule, their contents were 49. 62% and 12. 03% in all 133 random Eubacteria clones respectively. The results of RTQ-PCR indicated that the content of Archaea was less than Eubacteria, the Archaea content in total microorganisms in SMD granule was about 27. 6%.     

浑河底泥产甲烷古菌多样性空间分布特征

为了深入探究影响河流甲烷排放的关键因素,采用PCR-RFLP(限制性片段长度多态性聚合酶链反应)技术及测序分析对浑河底泥产甲烷古菌的多样性及空间分布进行了研究.结果表明,浑河底泥产甲烷古菌划分为4大类群:甲烷杆菌目(Methanobacteriales)、甲烷微菌目(Methanomirobiales)、甲烷胞菌目(Methanocellales)和甲烷八叠球菌目(Methanosarcinales).从河流上游到下游,产甲烷古菌的群落结构呈现出空间变异的特征.河流上游占优势的产甲烷古菌菌属为Methanosarcina和Methanospirillum,分别约占46.2%和20.8%;中游主要菌属为Methanosarcina、Methanobacterium和Methanomethylovorans,分别约占40.9%、20.7%和15.2%;下游主要菌属为Methanosarcina和Methanobacterium,分别约占46.7%和22.1%.浑河底泥中Methanosarcina为优势菌属.Shannon指数(H')和Simpson多样性指数(D)计算结果表明,河流上游(H'=1.56,D=0.33)和中游(H'=1.79,D=0.26)产甲烷古菌的多样性与下游(H'=1.65,D=0.32)均较为接近.     

UASB反应器处理含蛋白质废水颗粒污泥形成的研究

以含蛋白质废水为基质,UASB反应器内培养颗粒污泥的试验结果表明,控制反应器出水 pH在7.2—7.5之间,出水丙酸浓度不超过300mg/L条件下,污泥负荷大于0.67kg COD/kgVSS·d时反应器内形成了颗粒污泥.MPN法计数发酵性细菌、丙酸分解菌、丁酸分解菌、乙酸裂解产甲烷菌和甲酸/H_2+CO_2,产甲烷菌的数量,只有当各类群细菌数量达到一定水平并且有合适的比例时才能形成颗粒污泥,颗粒污泥成熟后其组成相对稳定.颗粒污泥同接种污泥相比,其最大比产甲烷活性提高较大,是细菌数量增加的缘故。     

产氢产乙酸和产甲烷反应对厌氧消化的限速作用

为明晰厌氧消化过程的主要限速步骤,分别以丁酸、乙酸、H₂/CO₂为基质,在37℃和pH 5.00~9.00条件下对厌氧活性污泥进行培养,依据Shelford耐受定律对食丁酸产氢产乙酸菌（SBOB）、乙酸营养型产甲烷菌（ACM）和氢营养型产甲烷菌（HTM）的pH值生态幅及基质转化速率进行分析.结果表明,SBOB、ACM和HTM的pH值生态幅分别为6.19~8.59、5.50~7.74和4.39~9.23,其代谢最适pH值分别为7.39、6.62和6.81.在最适pH值条件下,厌氧活性污泥对丁酸、乙酸、H₂/CO₂的转化速率分别为0.86、1.04和1.09gCOD_equ/（gMLVSS·d）.可见,与产甲烷菌相比,产氢产乙酸菌的pH值生态幅更窄,基质转化速率更慢,对厌氧消化过程具有更为显著的限制作用.     

新乡市镉污染土壤细菌群落组成及其对镉固定效果

重金属污染土壤中具有丰富的微生物群落组成,为生物修复提供了微生物资源.本研究以新乡市某电池厂周边Cd污染土壤为研究对象,采用高通量测序和平板分离方法分析其细菌群落组成.传统培养方法表明新乡市重金属污染土壤细菌由厚壁菌门、放线菌门、变形菌门和拟杆菌门这4个门,芽孢杆菌属、节杆菌属和根瘤菌属等30个属组成;高通量测序表明,其由变形菌门、放线菌门和酸杆菌门等25门及400属组成.相较于培养方法,高通量测序群落组成更为丰富.基于高通量测序的分子生态网路分析表明其关键细菌分别为Arthrobacter、Marmoricola、Nocardioides、Ferruginibacter、Flavitalea、Nitrospira和Lysobacter等组成.对分离的159株可培养菌株进行Cd摇瓶吸附实验,结果表明Aneurinibacillus、Arthrobacter和Bacillus等11个属的30株菌具有较好地固定效果.效果验证实验表明,Ochrobactrum sp. 1-6、Bacillus sp.2-11和Pseudomonas sp.1-9等6株高效菌株能提高青菜(鸡毛菜)生物量、降低青菜不同组织中的Cd含量.本研究为新乡市重金属污染土壤修复提供菌种资源,同时为重金属污染土壤细菌群落和功能提供参考依据.     

南京市4个污水处理厂的活性污泥中细菌的分离鉴定和抗生素耐药性分析

通过16S rDNA序列分析对南京CN、CE、JN和JM这4个污水处理厂的活性污泥中分离的细菌进行鉴定,采用Kirby-Bauer纸片琼脂扩散法分析细菌的抗生素耐药性,目的是阐明该地区污水处理厂活性污泥中细菌抗生素耐药性现状,探索污水及污泥的潜在环境风险.4个污水处理厂分别分离到7、9、8和11株菌落形态不同的细菌,上述35株细菌分属25个种,17个属.抗生素耐药性分析显示,97.1%的菌株具有抗生素耐药性,80%菌株具有多重耐药性.分离菌株对氨苄西林、卡那霉素、氯霉素、链霉素、庆大霉素、四环素、红霉素和大观霉素的耐药率分别为71.4%、37.1%、37.1%、57.1%、34.3%、68.6%、94.3%和65.7%.结果表明活性污泥中细菌耐药性严重;不同菌株间的耐药性分析显示,危害水产养殖业的病原菌气单胞菌具有严重的多重耐药性,所有芽孢杆菌对氯霉素、链霉素和庆大霉素敏感;污水处理厂应加强出水的消杀工作,避免二次污染.