SBR中SRT对总细菌群落结构的影响研究

为了揭示序批式反应器不同污泥停留时间(SRT)下总细菌群落结构的异同及SRT变化对总细菌群落结构的影响,应用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)进行研究。通过克隆测序发现,不同的SRT条件下生物多样性和种群结构会有所差异,既存在各SRT条件下相同的优势菌群(Escherichia coli和Aeromonas sp.),也存在某些SRT下特有的优势菌群(Uncultured Peptostreptococcaceae),SRT为40 d时检测到以降解硫酸盐获得能源的优势微生物。研究还表明,SRT为40 d时多样性指数取得最大值,各SRT条件下微生物的种群相似性差别较大。     

抗生素菌渣堆肥进程中微生物群落的变化

将青霉素菌渣、林可霉素菌渣与牛粪等原料分别进行好氧堆肥实验,以考察堆肥过程中不同菌渣对微生物群落的影响。在堆制的41d里,根据温度变化分阶段采集堆肥样品,采用稀释倒平板法测定细菌、放线菌和真菌的数量。结果表明,菌渣不同,其堆肥中的微生物群落变化趋势不同。青霉素菌渣堆肥中细菌数量变化趋势为高一低,真菌数量变化趋势为高一低．高,放线菌数量为逐渐增加;林可霉素菌渣堆肥过程中细菌数量变化趋势为低一高一低,放线菌和真菌数量变化趋势为高．低．高。依据真菌菌落形态观察,菌渣堆肥中的真菌种类比对照牛粪堆肥单一,表明两种菌渣对堆肥中的微生物多样性均产生了不利影响。林可霉素菌渣堆肥初始时的细菌数量比对照低1个数量级,放线菌数量在整个堆肥进程中都明显低于对照,堆肥结束时,随着菌渣含量的增加,放线菌数量逐渐下降,高温期真菌数量下降幅度随着菌渣含量增加而加大,表明林可霉素菌渣对细菌、放线菌和真菌均有不同程度的抑制。堆肥化后菌渣中林可霉素残留量的减少表明,在一定条件下堆肥处理可以将抗生素菌渣无害化和资源化。     

超声波-缺氧／好氧污泥消化反应器中氨氧化细菌群落结构的演变

为了揭示超声波-缺氧／好氧污泥消化反应器中氨氧化细菌群落结构多样性的演变过程,采用变性梯度凝胶技术（PCR—DGGE）研究不同运行时期氨氧化细菌群落结构的变化。DGGE分析表明,反应器中氨氧化细菌群落比较丰富。在反应器运行的不同时期,氨氧化细菌的群落结构发生了一定的变化,反映了种群的动态演变。UPGMA聚类分析将DGGE图谱分为3大类群并对应于各自的运行时期。测序结果表明,反应器中的优势种群属于变形菌门（Proteobacteria）,包括α-proteobacteria,β-proteobacteria,γ-proteobacteria和ε-proteobacteria4个纲,其中β-proteobacteria占45％,γ-proteobacteria占40％。在始终保持明显优势地位的种属中,5株为反硝化细菌,它们对提高反应器脱氮效率具有重要作用。     

Short-term impact of olive mill wastewater (OMWW) applications on the physico-chemical and microbiological soil properties of an olive grove in Argentina

The purpose of this work was to investigate the effects of spreading olive oil mill wastewater (OMWW) on soil biochemical parameters and olive production in an organically managed olive orchard. The experiment was carried out with three different doses of OMWW (80, 160 and 500 m³ ha^?1) and a control (untreated soil). Three samplings were done at 10, 30 and 90 days after the administration of the byproduct. OMWW application differentially modified the biochemical properties of the soil analyzed. Organic matter, organic carbon, total nitrogen and extractable phosphorus soil contents increased proportionally with each increasing dose. The values of these parameters decreased gradually with time. Total microbial activity was altered and the OMWW 500 m³ ha^?1 treatment proved to be the most active when compared with the other applied doses. OMWW agricultural application also modified the structure of soil microbial communities, particularly affecting Gram positive and negative bacteria, while fungal biomass did not show consistent changes. Although there was a salinity increase in the treated soil, especially at the highest dose, the productive parameters analyzed (fruit and oil tree^?1) were not affected. In light of the obtained results, we consider that low dose of OMWW could be considered an alternative farming practice for semiarid regions.     

Influence of tetracycline exposure on the growth of wheat seedlings and the rhizosphere microbial community structure in hydroponic culture

In this study, the effects of tetracycline exposure on wheat growth and the microbial community structure in the rhizosphere were investigated under hydroponic culture conditions. Exposure to various concentrations of tetracycline resulted in significant suppression of the growth of wheat roots and shoots, with minimum doses of 0.8 mg L^?1 and 4 mg L^?1 resulting in inhibition rates of 32% and 15.4%, respectively. Complete inhibition of the growth of these two parts of wheat plants was observed in response to treatment with tetracycline at 20 mg L^?1 and 100 mg L^?1, respectively. However, the germination of wheat seeds was not sensitive to exposure to tetracycline. The effects of tetracycline exposure on the microbial community in the wheat rhizosphere were evaluated through traditional cultivation and molecular biological analyses. The cultivation results indicated that bacteria were the dominant population, being present in concentrations of 1× 10⁸–2.45× 10⁹CFUs mL^?1, although 39% to 87% inhibition occurred in response to tetracycline. The concentration of fungi increased in all tetracycline treated samples to 2.5 to 15.8 times that of the control. The highest concentration of fungi (4.27× 10⁸ CFU mL^?1) was observed in response to 60 mg L^?1 tetracycline after 15 days of cultivation. In this stage, a large amount of fungal colonies was observed on the surface of the culture solution, the wheat roots became rotted and the plants became atrophic or even died. Molecular biological analysis indicated that the bacterial community structure was significantly different in samples that were exposed to high levels of tetracycline (over 20 mg L^?1) than in samples that were exposed to lower concentrations. As the concentration of tetracycline increased, the diversity of the bacteria decreased. Additionally, several dominant sensitive species such as Sphingobacterium multivorum were suppressed by tetracycline, while some resistant species such as Acinetobacter sp. appeared or were conserved. The bacteria population tended to stabilize when the drug concentration exceeded 40 mg L^?1.     

Influence of ciprofloxacin on the microbial catabolic diversity in soil

In this study, the effect of ciprofloxacin (CIP) on the catabolic diversity of soil microbial communities was evaluated. Soil samples were spiked with ciprofloxacin (0, 1, 5 and 50 mg?kg^?1) and were incubated for 1, 3, 9, 22 and 40 days. Untreated controls received only water. The functional diversity of the microbial community studied was characterized using a catabolic response profile (CRP). Six substrate groups were tested: carbohydrates, amino acids, carboxylic acids, aromatic chemicals, alcohols and polymers. After 40 days, the CIP concentrations in the soil samples ranged from 25% to 58% of the initial concentrations. Soil respiratory responses to the individual substrates D-glucose, lactose, D-mannose, L-glutamic, Na-citrate, malic acid and inosine were inhibited at the high CIP concentrations (5 and 50 mg·kg^?1) in the soils and were increased at the lowest CIP concentration (1 mg·kg^?1). Soil respiration was inhibited at all of the CIP concentrations after the addition of D-galactose and glycerol. The CIP concentration and incubation time explained 45.3% of the variance of the catabolic responses. The CRP analysis clearly discriminated among the different CIP concentrations. The results suggest that CIP strongly affects the catabolic diversities of soil microbial communities and that its effect is more significant than that of incubation time.     

Ni2＋对活性污泥活性及群落多样性的影响

通过检测活性污泥的电子传递体系活性以及生物多样性,研究Ni2＋对活性污泥微生物活性及群落多样性的影响。结果表明：与对照系统相比,5mg／L的Ni2＋对2,3,5-lriphenylteItrazoliumchloride（TTC．ETS）活性未产生显著的影响;但当Ni2＋的浓度进一步增大到10、20和40mg／L后,其对序批式反应器内活性污泥TTC—ETS活性的抑制率分别达到（36．794-11．14）％、（55．88±13．90）％和（70．97±6．78）％。低浓度Ni2＋．能增强活性污泥微生物对碳源的利用,但高于10mg／L的Ni2＋则显著抑制了活性污泥微生物对碳源的利用。各个SBR系统中微生物群落最常见的物种相近,物种丰富度和均一性则均有所不同,其中群落物种丰富度随着Ni2＋浓度的增加而逐渐减小。TTC—ETS活性、平均每孔颜色变化率、Shan—liOn指数和Simpson指数,与Ni2＋的胁迫浓度之间的显著相关性表明,它们均可有效地表征Ni2＋胁迫对活性污泥微生物活性及群落多样性的影响程度。     

磺胺和四环素类抗生素对活性污泥性能的影响

废水处理工艺中抗生素类污染物的存在可能会对生物处理过程产生长期而深远的影响,为探明此类污染物对废水生物处理主体活性污泥性能等方面的影响,采用间歇培养法研究了活性污泥法处理污水时,抗生素类污染物的存在对活性污泥性能如胞外聚合物（EPS）、污染物处理能力、脱氢酶活性和群落结构的影响。结果表明,抗生素的存在会导致活性污泥的胞外聚合物总量及其主要组分蛋白质和多糖增加,以产生保护屏障;且由于污泥絮体解体,细胞破裂导致EPS中DNA和色氨酸含量增加。同时,由于蛋白质大量增加引起的表面负电荷的增加,使污泥疏水性增强,絮凝性能恶化;污泥絮体解体导致污泥颗粒变小,SVI也随之下降;在活性污泥脱氢酶活性急剧下降的同时,出水TOC迅速升高。此外,抗生素类污染物在抑制活性污泥中大部分细菌的同时,对部分菌群也有刺激生长作用,最终导致活性污泥生物群落结构的改变。四环素类抗生素对活性污泥的EPS和絮凝沉降性能的影响大于磺胺类,而对污水处理能力和群落结构的影响则不如磺胺类。抗生素类污染物的长期存在会对活性污泥沉降性能、絮凝性能、脱氢酶活性以及活性污泥群落结构等产生一系列负面影响,进而影响污染物去除效果,导致出水水质恶化。     

施用城市污泥堆肥对土壤微生物群落结构变化的影响简

在温室条件下进行了15周的盆栽实验,考察了施用城市污泥堆肥后,土壤中养分含量的变化规律,重点研究了施用城市污泥堆肥对土壤微生物群落结构变化的影响。实验发现,污泥堆肥能改善土壤养分,有机质和氮、磷含量得到显著提高。经PCR-DGGE分析,施肥1周后土壤中细菌和真菌的群落结构均发生了较大的变化。随着施肥时间的延长,细菌在富含有机质及氮、磷等养分的土壤环境下大量生长,多样性提高,其优势菌群属于γ变形菌、α变形菌和芽单胞菌;随着有机质的不断消耗,细菌的生长活性受到抑制,最终由于养分的缺乏,细菌种群多样性呈现小幅度的降低,优势菌群变为绿弯菌门、γ变形菌亚纲和厚壁菌门。对于真菌,其多样性指数在堆肥前3周逐渐提升,在第3~12周的监测中呈现相对稳定的变化趋势,优势菌群主要为座囊菌纲和散囊菌纲。     

连续流砂过滤器深度处理市政污水的中试研究

采用好氧/缺氧连续流砂过滤器中试实验研究深度处理北京某污水处理厂二级出水。实验结果表明,当连续流砂过滤器好氧段聚合氯化铝投量为20 mg/L,缺氧段碳源投量为32 mg/L时,COD、NH+4-N、TN和TP的平均去除率分别为34.77%、86.54%、66.94%和84.10%,最终出水均达到北京市新(改、扩)建城镇污水处理厂排放A标准(DB11/890-2012)。克隆文库法分析石英砂表面生物膜中的细菌群落结构表明,其优势菌群为β-proteobacteria,其中大部分能以废水中碳源为电子供体还原硝酸盐。