Analysis of bacterial community structures in two sewage treatment plants with different sludge properties and treatment performance by nested PCR-DGGE method

The bacterial community structures in two sewage treatment plants with different processes and performance were investigated by denaturing gradient gel electrophoresis （DGGE） of nested polymerase chain reaction （nested PCR） amplified 16S rRNA gene fragments with group-specific primers. Samples of raw sewage and treated effluents were amplified using the whole-cell PCR method, and the activated sludge samples were amplified using the extracted genomic DNA before the PCR products were loaded on the same DGGE gel for bacterial community analysis. Ammonia-oxidizing bacterial and actinomycetic community analysis were also carried out to investigate the relationship between specific population structures and system or sludge performance. The two plants demonstrated a similarity in bacterial community structures of raw sewage and activated sludge, but they had different effluent populations. Many dominant bacterial populations of raw sewage did not appear in the activated sludge samples, suggesting that the dominant bacterial populations in raw sewage might not play an important role during wastewater treatment. Although the two plants had different sludge properties in terms of settleability and foam forming ability, they demonstrated similar actinomycetic community structures. For activated sludge with bad settling performance, the treated water presented a similar DGGE pattern with that of activated sludge, indicating the nonselective washout of bacteria from the system. The plant with better ammonium removal efficiency showed higher ammonia-oxidizing bacteria species richness. Analysis of sequencing results showed that the major populations in raw sewage were uncultured bacterium, while in activated sludge the predominant populations were beta proteobacteria.     

Start-up performances of dry anaerobic mesophilic and thermophilic digestions of organic solid wastes

Two dry anaerobic digestions of organic solid wastes were conducted for 6 weeks in a lab-scale batch experiment for investigating the start-up performances under mesophilic and thermophilic conditions. The enzymatic activities, i.e., β-glucosidase, N-α-benzoyl-Largininamide （BAA）-hydrolysing protease, urease and phosphatase activities were analysed. The BAA-hydrolysing protease activity during the first 2-3 weeks was low with low pH, but was enhanced later with the pH increase. β-Glucosidase activity showed the lowest values in weeks 1-2, and recovered with the increase of BAA-hydrolysing protease activity. Acetic acid dominated most of the total VFAs in thermophilic digestion, while propionate and butyrate dominated in mesophilic digestion. Thermophilic digestion was confirmed more feasible for achieving better performance against misbalance, especially during the start-up period in a dry anaerobic digestion process.     

油田硫酸盐还原菌快速定量检测方法

现有油田废水中硫酸盐还原菌检测周期长、检测费用较高,本研究应用聚合酶链式反应(PCR)技术与倍比稀释法(MPN)相结合的DSR-MPN-PCR法,对硫酸盐还原菌进行快速定量检测.从废水中制备了直接用于PCR扩增的菌液,保证了定量准确性;建立以硫酸盐还原菌亚硫酸盐还原酶基因(Dsr)为靶位点的通用探针DSR1F和DSR5R的反应体系和扩增条件.结果表明,该方法检测灵敏度明显比液体稀释培养法高2个数量级,真实地表征了废水中实际的SRB菌数量,整个操作过程需要3～4　h,检测结果非常稳定,降低了检测费用,可以在生产中应用.     

Response of anaerobes to methyl fluoride, 2-bromoethanesulfonate and hydrogen during acetate degradation

To use the selective inhibition method for quantitative analysis of acetate metabolism in methanogenic systems,the responses of microbial communities and metabolic activities,which were involved in anaerobic degradation of acetate,to the addition of methyl fluoride(CH3F),2-bromoethanesulfonate(BES)and hydrogen were investigated in a thermophilic batch experiment.Both the methanogenic inhibitors,i.e.,CH3F and BES,showed their effectiveness on inhibiting CH4 production,whereas acetate metabolism other than acetoclastic methanogenesis was stimulated by BES,as reflected by the fluctuated acetate concentration.Syntrophic acetate oxidation was thermodynamically blocked by hydrogen(H2),while H2-utilizing reactions as hydrogenotrophic methanogenesis and homoacetogenesis were correspondingly promoted.Results of PCR-DGGE fingerprinting showed that,CH3F did not influence the microbial populations significantly.However,the BES and hydrogen notably altered the bacterial community structures and increased the diversity.BES gradually changed the methanogenic community structure by affecting the existence of different populations to different levels,whilst H2 greatly changed the abundance of different methanogenic populations,and induced growth of new species.     

高浓度难降解工业废水菌种筛选及其降解特性

使用富集、稀释涂平板的方法从制药、染料、化工及精细化工、食品等多家工厂的混合高浓度难降解化工废水中筛选到8株细菌,经16S rDNA鉴定为Bacillus aquimaris、Enterobacter、Pseudomonas putida、Microbacterium、Agrobacterium、Alpha proteobacterium、Planococcus rifietoensis,其中两株细菌为Bacillus aquimaris。对各单一菌种生长条件的研究表明,各菌种生长的最适pH为7,最适接种量为15%（v/v）,最适生长温度为37℃,其中Pseudomonas putida的最适生长温度为30℃。在最适生长条件下,研究了各单一菌种及不同组合的混合菌种对废水的降解效果,结果表明在单一菌种中Pseudomonas putida对废水的降解效果最优,混合菌的降解效果优于单一菌种的降解效果,混合菌可将废水COD由1 249 mg/L降至97 mg/L,比普通活性污泥对废水的去除率提高了14.7%。     

缺氧嗜甲烷古菌研究进展

综述了缺氧嗜甲烷古菌的分布、生态位、形态与代谢特征的新发现,并讨论了其与产甲烷菌的关系.在无氧条件下,缺氧嗜甲烷古菌与硫酸盐还原菌互养,氧化甲烷气体以阻止其进入大气.缺氧嗜甲烷古菌主要分布于深海甲烷渗漏区和冷泉区域,在其他多种缺氧环境中也能发现,由于还未获得纯培养,对这类微生物的生态位知之甚少.其细胞呈球状、杆状,有时聚集成球状集合体或连接形成丝状体.缺氧甲烷氧化可能经过"反甲烷合成"、"甲基合成"等路径.嗜甲烷古菌与产甲烷菌有着较近的亲缘关系,并且存在许多相似点.图1表1参37     

碱性介质中还原高浓度Cr(VI)细菌的分离及其特性

目前国内外处理含铬废水的微生物仅局限于酸性或中性环境,且处理Cr(VI)的浓度仅为200mgL-1左右,难以工业化应用,尤其是不可能处理诸如铬渣渗滤液之类的碱性含铬废水及铬渣.本研究从铬渣堆埋场附近取得菌样,经富集、分离、驯化,得到能在碱性介质中高效还原Cr(VI)的无色杆菌属(Achromobactersp.)菌株,该菌为G-,具有周身鞭毛及可运动性.对其生理及还原Cr(VI)的特性进行了研究,结果表明:该菌嗜碱,好氧,耐盐及高Cr(VI),在有氧、pH为10.30、30℃等条件下,含Cr(VI)1570mgL-1的废水经该菌处理16h后浓度降至0.6mgL-1.处理后的沉淀物中铬以Cr(OH)3的非晶形态存在,其中总铬含量为21.44%,Cr(VI)检测不出,具有很大的回收价值.图4表3参16     

3株溶藻细菌溶藻特性的初步研究

对3株溶藻细菌L7、L8和L18溶解水华鱼腥藻(Anabaena flos-aquae FACHB-245)的溶藻方式、溶藻活性代谢产物的溶藻特性进行了研究。3株菌都为间接溶藻,产生具有热稳定性的、对水华鱼腥藻有较强溶藻效果的活性代谢产物。L8的溶藻效果与藻液中投加溶藻活性代谢产物的浓度呈正相关。处于衰减期的L8,其溶藻活性代谢产物的溶藻效果好于对数生长期和稳定期。在不同pH值条件下进行溶藻实验,当pH值为8.5±0.1时,L7溶藻活性代谢产物的去除率达到85.78%;当pH值为10±0.2时,L8和L18溶藻活性代谢产物的去除率分别达到92.84%和78.72%;由7×108cells/mL的L8菌液获得的无菌滤液,当投加量<30%时,对水华鱼腥藻的生长具有促进作用。     

高硫抗生素废水微好氧连续处理系统的进水负荷效应研究

在14~18℃条件下探讨了不同进水负荷对高硫抗生素废水微好氧连续处理系统的处理效果和污泥中细菌、酵母菌含量的影响.结果表明,在低负荷[COD=2 kg.(m3.d)-1]条件下,污泥以细菌为优势菌群(细菌含量为96%),污泥浓度和污泥脱氢酶活性(TF/MLSS.t)分别为300 mg.L-1、4300 mg/(g.h),污泥SVI=35 mL.g-1,COD去除率仅为13%;当升高负荷至初始负荷的5倍和10倍时,污泥中以酵母菌为优势菌(酵母菌含量分别为67%和71%),污泥浓度分别为2300、1500 mg.L-1,污泥DHA活性(TF/MLSS.t)分别为9600、10800 mg/(g.h),污泥SVI值分别为160、110 mL.g-1,COD去除率升高到40%~50%,进水负荷对污泥微生态构成和系统处理效果均具有显著影响.     

一株利用生物柴油废水产氢的光合菌的筛选、鉴定

从37株光合细菌中筛选出1株能够利用甘油做碳源进行有效产氢的菌株(DB803).根据该菌株的形态、生理生化特征、16S rDNA序列和ERIC-PCR结果分析,初步鉴定该菌株为类球红细菌(Rhodobacter sphaeroides).研究了该菌株在30℃, 4000lx光照厌氧条件下利用不同浓度的生物柴油废水产氢的能力,当培养基起始COD浓度为11.5g/L时,其在对数生长期平均产氢速度为38mL/(L·h),同时,废水COD去除率达91.2%.