现代分子生物技术在废水菌群监测中的应用

荧光原位杂交、DNA指纹等现代分子生物技术在废水治理过程中得到了广泛的应用。对现代分子技术的分类及其在废水菌群监测中的应用进行了简要的论述,并通过各类技术间的比较,提出其潜在的问题及应用前景。     

Comparison of beach bacterial water quality indicator measurement methods

Three methods (membrane filtration, multiple tube fermentation, and chromogenic substrate technology kits manufactured by IDEXX Laboratories, Inc.) are routinely used to measure indicator bacteria for beach water quality. To assess comparability of these methods, quantify within-laboratory variability for each method, and place that variability into context of variability among laboratories using the same method, 22 southern California laboratories participated in a series of intercalibration exercises. Each laboratory processed three to five replicates from thirteen samples, with total coliforms, fecal coliforms or enterococci measured depending on the sample. Results were generally comparable among methods, though membrane filtration appeared to underestimate the other two methods for fecal coliforms, possibly due to clumping. Variability was greatest for the multiple tube fermentation method. For all three methods, within laboratory variability was greater than among laboratories variability.     

Seasonal Variation in Bacterial Flora of the Wastewater and Soil in the Vicinity of Industrial Area

Environmental pollution is one of the major problems being facedtoday due to the advent of extensive industrialization. Heavy metals are the most important contaminants in wastewater that are present in abundance and are toxic. Heavy metal contentsof sewage in the industrial estate of Aligarh (U.P.) have beendetermined by atomic absorption spectrophotometry. The analysisof samples collected from six different locations revealedsignificantly high levels of Fe, Zn, Cu, Cr and Ni. Certainbacteriological (Total bacterial count, Total coliform, Fecal coliform, and Fecal Streptococci) parameters of domestic and industrial sewage as well as soils were monitored from March1990 to January 1993. Total bacterial count, total coliform,fecal coliform and fecal streptococci were found to be lowestin all the samples of industrial wastewater compared to thosein domestic sewage and soil systems. The soil however, contained highest total culturable bacterial population. In view of the common practice of the application of sewage to agricultural land in the neighbouring area, the discharge ofindustrial wastewater without proper treatment into public sewers should be strictly prohibited.     

An Italian Study on Cryptosporidium and Giardia in Wastewater, Fresh Water and Treated Water

Cryptosporidium oocysts and Giardia cysts has been isolated from waters worldwide. In Italy, studies on these parasites in the environment are still limited due to absence of epidemiological evidence and difficulty of adequate methodologies of sampling and analysis. The new Drinking Water Directive 98/83/CE states that Cryptosporidium has to be determined in water intended for human consumption if Clostridium perfringens is detected. This investigation contributes to the knowledge of both Cryptosporidium and Giardia occurrences in Italian aquatic environments through a two-year monitoring program. In addition, indicator bacteria and Clostridium perfringens were monitored in sewage, surface waters, drinking water, and swimming pools and possible correlations were calculated among all the selected parameters. Cysts and oocysts were detected in sewage and surface water and Giardia numbers always prevailed over Cryptosporidium. The parasites were not detected in drinking water, while a positive sample was obtained from the analysis of swimming pools. Pearsons correlation coefficients evidenced a reciprocal correlation between both the protozoa and the Enterococci counts.     

底泥中红霉素耐受菌群的多样性分析

为了正确评估抗生素残留的环境风险,了解长期受低浓度红霉素污染条件下,水体底泥中红霉素耐受菌群结构的变化特点,采用传统的微生物培养法和分子生物学方法对长期受低浓度红霉素污染的水体底泥中红霉素耐受菌群结构的多样性进行了分析.结果表明:采用传统的培养方法,从底泥中可分离筛选出3株对红霉素有耐受能力的菌株,根据其形态学特征及16S rDNA序列分析,初步鉴定为赖氨酸芽孢杆菌(Lysinibacillussp.)、土壤芽孢杆菌(Solibacillus silvestris)以及蜡样芽孢杆菌(Bacillus cereus),其中敏感菌蜡样芽孢杆菌经低浓度红霉素诱导对红霉素表现出一定的耐药性.进一步构建底泥耐药菌群16S rDNA克隆文库发现,底泥中红霉素耐受菌群可分为三大类群,其中未获培养的细菌(Uncultured bacterium)在整个文库中比例最大,占65.06%,其次为芽孢杆菌纲(Bacilli)和梭菌纲(Clostridia),分别占文库比例33.73%和1.20%.文库中可培养的耐药菌优势类群为芽孢杆菌纲,与传统培养方法得到的结果相一致.上述研究表明,在长期受低浓度红霉素污染的环境中,红霉素耐药菌的存在具有一定的广泛性和潜在性,将可能威胁人类健康和生态系统,应当重视其生态风险评价与管理.     

能源植物修复土壤镉污染过程中细菌群落分析

选取油脂类能源植物大豆和碳水化合物类能源植物玉米,采用高通量测序方法研究大豆、玉米修复Cd污染土壤过程中根际土壤细菌群落组成.结果表明,100 mg·kg-1Cd的添加会抑制玉米、大豆生长,其中,大豆生物量降低比玉米高.不同组织中根部Cd积累量最高,转移系数TF分别为0.56(玉米)和0.14(大豆).基于Mi Seq的群落分析表明,大豆、玉米根际土壤细菌主要包括Proteobacteria(变形菌门)、Acidobacteria(酸杆菌门)、Gemmatimonadetes(芽单胞菌门)、Actinobacteria(放线菌门)、Bacteroidetes(拟杆菌门)等33个门.细菌群落的PCo A和UPGMA分析表明,Cd的添加和能源植物种植均能对细菌群落结构产生影响,其中,Cd的添加影响最大.Gemmatimonas、Flavisolibacter、Flexibacter、Ramlibacter、Ohtaekwangia、Flavitalea等细菌在Cd胁迫条件或大豆、玉米种植条件下相对丰度有所变化,分析其可能在大豆、玉米耐受Cd污染中起作用.     

涠洲采油废水处理系统运行效果及微生物群落分析

涠洲终端处理厂选用ABR+SBR联合工艺处理采油废水,该系统运行稳定,处理效果好。进水ρ(COD)、ρ(石油类)分别为215~731,9~52 mg/L,系统处理后出水浓度为30~87,2~8 mg/L,去除率为83%~94%,78%~92%。废水中其余指标如S2-、SS和NH3-N去除率分别为99%、94%和70%~90%。利用分子分析法对微生物群落结构研究,表明进水较出水有更高的细菌丰度,出水较进水有更高的真菌丰度。推测活性污泥中Marinobacterium、Marinobacter和Thiomicrospira是系统中采油废水主要降解细菌。此外,真菌群落分布均匀主要为子囊菌门、担子菌门、接合菌门,兼性菌如Aspergillus、Alternaria、Fusarium、Blastobotrys及Meyerozyma在活性污泥中较为丰富,Aspergillus、Alternaria可能是潜在的降解真菌。     

饮用水净化工艺中磷的去除研究

利用一种新的微生物学分析方法,研究了原水中微生物可利用磷(MAP)以及总磷(TP)、溶解性正磷酸盐(SRP)在净水工艺中的去除情况.结果表明,生物预处理、生物活性炭及常规的混凝沉淀砂滤工艺均使水中的MAP、TP及SRP大大降低;生物预处理和生物活性炭对水中MAP的去除效率高于对TP的去除效率;常规处理对原水中MAP的去除率超过90%,TP的去除率在80%以上.臭氧氧化对水中TP和SRP的影响不大,但是使MAP增加.试验原水经过净水处理后,水中可供细菌利用的磷源降低到很低的水平,说明处理后的水中磷源可能成为水中细菌生长的限制因子.     

促生剂投量对菌剂-促生剂协同修复沉积物的影响

采用5个110 L的模拟河道反应器,在投加菌剂的基础上(底泥稳定后向底泥和水中分别注射浓度为0.09%和0.03%的菌剂),生物促生剂投量分别设计为0(空白对照实验)、0.08、0.09、0.10和0.11 g·L~(-1),通过为期115 d的修复实验研究菌剂与促生剂协同作用时底泥微生物群落特征变化规律,进而分析其对底泥修复效果的影响.实验表明,投加促生剂后,115 d时Chloroflexi、Proteobacteria、Firmicutes、Betaproteobacteria及Bacteroidetes等主要功能菌群相对丰度增加,脲酶活性与蛋白酶活性后期时总体上低于单独投加菌剂组.促生剂投量为0.10 g·L~(-1)时,上覆水COD_(Cr)稳定浓度为16.82 mg·L~(-1),低于其余各组;底泥TOC含量由初始的0.808%下降至第115 d时的0.687%,去除率为14.9%,显著高于其余各组;促生剂投量为0.11 g·L~(-1)时,底泥全氮去除率最高为14.8%.生物促生剂促使微生物群落向更适宜降解去除氮素及有机质的方向演替,有效改善底泥环境.     

抗番茄青枯病复合菌剂的筛选构建及其防效

通过土壤浸出液培养基和菌间相互拮抗试验,筛选并构建出由能拮抗土传病原菌的拮抗菌系和与之协同、快速繁殖的营养菌系组成的复合菌剂.复合菌剂在25～40 ℃,pH=6.0～8.0条件下生长良好.对番茄青枯病的平板拮抗试验的结果表明,复合菌剂对番茄青枯病病原菌、病土及番茄青枯病株中的微生物均有明显拮抗作用.盆栽试验结果显示,施入复合菌剂,可延缓病土的青枯病发病时间8～19 d并减少发病株数2～3株,防效明显.