河岸过滤中氨氮的削减及其浓度对细菌与氨氧化微生物的影响

通过小试滤柱模拟河岸过滤,结合荧光定量PCR和高通量测序等手段研究了河岸过滤对氨氮的削减效能和进水氨氮浓度对细菌与氨氧化微生物的影响.结果表明,低浓度（0.2 mg·L^-1）氨氮未被削减,较高浓度（1.0 mg·L^-1和2.0 mg·L^-1）氨氮的削减率可达70%.进水处细菌丰度随氨氮浓度升高而增加,细菌群落组成随氨氮浓度升高发生规律性变化.出水处氨氧化古菌（Ammonia oxidizing archaea,AOA）丰度与氨氮浓度呈负相关,氨氧化细菌（Ammonia oxidizing bacteria,AOB）丰度与氨氮浓度无显著相关关系;进水处AOA-α多样性与氨氮浓度呈正相关,但AOB-α多样性与氨氮浓度呈负相关;进水处AOA群落组成受氨氮浓度影响,而进、出水处AOB群落组成均受氨氮浓度影响.可见,进水氨氮浓度会影响河岸过滤对氨氮的削减效能,还会影响细菌、氨氧化微生物的丰度及群落结构,AOB对氨氮浓度的变化比AOA更敏感.     

三亚河红树林表层沉积物中好氧氨氧化微生物的分布特征及潜在硝化速率

氨氧化过程是硝化作用的限速步骤,氨氧化细菌(ammonia-oxidizing bacteria, AOB)和氨氧化古菌(ammonia-oxidizing archaea, AOA)是氨氧化作用的主要驱动者,其分布特征及其对硝化作用的相对贡献是氮素循环的研究热点.采用实时荧光定量PCR技术研究了三亚河红树林表层沉积物中好氧氨氧化微生物的分布特征,并通过测定潜在硝化速率分析了AOB和AOA对硝化作用的相对贡献率.结果表明,多数采样点中,AOA amoA基因丰度高于AOB amoA基因丰度; AOB丰度冬季较高,AOA丰度夏季较高,且冬季AOA和AOB丰度的比值较低;溶解氧、pH、总有机碳和硝态氮对AOB和AOA丰度影响较大; AOB和AOA在夏季的潜在硝化速率均高于冬季,冬季AOA对硝化作用的相对贡献率较高而夏季则是AOB在硝化作用中占主导地位,AOB和AOA的潜在硝化速率与amoA基因丰度均不存在显著相关性.     

Microbiological characteristics in a zero-valent iron reactive barrier

Zero-valent iron (Fe⁰)-based permeable reactive barriertreatment has been generating great interest for passivegroundwater remediation, yet few studies have paid particularattention to the microbial activity and characteristics withinand in the vicinity of the Fe⁰-barrier matrix. The presentstudy was undertaken to evaluate the microbial population andcommunity composition in the reducing zone of influence byFe⁰ corrosion in the barrier at the Oak Ridge Y-12 Plantsite. Both phospholipid fatty acids and DNA analyses were usedto determine the total microbial population and microbialfunctional groups, including sulfate-reducing bacteria,denitrifying bacteria, and methanogens, in groundwater andsoil/iron core samples. A diverse microbial community wasidentified in the strongly reducing Fe⁰ environment despitea relatively high pH condition within the Fe⁰ barrier (up topH 10). In comparison with those found in the backgroundsoil/groundwater samples, the enhanced microbial populationranged from 1 to 3 orders of magnitude and appeared to increase from upgradient of the barrier to downgradient soil. Inaddition, microbial community composition appeared to change overtime, and the bacterial types of microorganismsincreased consistently as the barrier aged. DNA analysisindicated the presence of sulfate-reducing and denitrifyingbacteria in the barrier and its surrounding soil. However, theactivity of methanogens was found to be relatively low,presumably as a result of the competition by sulfate/metal-reducing bacteria and denitrifying bacteria because of the unlimited availability of sulfate and nitrate in the site groundwater. Results of this study provide evidenceof a diverse microbial population within and in the vicinity ofthe iron barrier, although the important roles of microbial activity, either beneficially or detrimentally, on the longevityand enduring efficiency of the Fe⁰ barriers are yet to be evaluated.     

木质素降解酶及其调控机理研究的进展

近年来有关木质素降解微生物和木质素降解酶的产与调控机理的研究表明，腐霉和细菌在木质自然降解中起着重要作用，腐霉的降解作用发生在次级代谢阶段，而细菌发生在初级代谢阶段，影响木质素降解酶的产生酶活力高低的因素有碳氮的选择与限制；诱导物的添加；表面活性剂的使用；某些金属离子浓度水平的改变；菌丝的固定化，温度和摇床转速的变换等。     

Distribution characteristics of ammonia-oxidizing bacteria in the Typha latifolia constructed wetlands using fluorescent in situ hybridization(FISH)

A molecular biology method, fluorescent in situ hybridization（FISH）, in which the pre-treatment was improved in allusion to the media of the constructed wetlands（CW）, e.g. the soil and the grit, was used to investigate the vertical distribution characteristics of ammonia-oxidizing bacteria（AOB） quantity and the relation with oxidation-reduction potential（ORP） in the Typha latifolia constructed wetlands under three different Ioadings in summer from May to September. Results showed that the quantity of the AOB decreased in the Typha latifolia CW with the increase of vertical depth. However, the AOB quantity was 2-4 times the quantity of the control in the root area. Additionally, ORP in the rhizosphere was found to be higher than other areas, which showed that Typha latifolia CW was in an aerobic state in summer when using simulated non-point sewage at the rural area of Taihu Lake in China and small town combined sewage.     

影响微生物絮凝剂产生的因素研究

本文通过改变培养基的种类、培养基的碳源、氮源、无机盐离子来选择絮凝剂产生菌“Dfjm-1”高效低廉的培养基 ;通过改变培养基初始 p H值、培养温度、培养过程中的通气量等因素 ,得出“Dfjm-1”菌株产生絮凝剂的最佳条件。Dfjm-1产生絮凝剂的最佳因素为 :培养基初始 p H值为 6.5～ 7.0 ,培养温度为 3 0℃ ,培养时间为 60小时左右 ,通气量为 :早期 :2 50 r/ min;中期 1 50 r/ min;后期 1 0 0～ 1 50 r/ min     

EM菌强化SBR脱氮除磷的试验研究

重点讨论了有效微生物群（EM）在SBR反应器中对生活污水的TP，NH3－N和TN和TN的去除效昆，结果表明，当EM投加量（VEM／V污水）为1／1000－1／1000时，能显著提高SBR工艺对TP，NH3－N和TN的去除率和降解速度，具有节能降耗的优点，当EM投加量（VEM／V污水）在1／1000－5／1000范围内，TN的去除率随EM量的增加而逐渐提高。     

Study on nitrile-degrading microorganisms

Two strains of bacteria were isolated from nitrile polluted soils, and identified as Corynebacterium boffmanii and Arthrobacter flavescens. Acetonitrile, propionitrile, butyronitrile and acrylonitrile were degraded by these bacteria to yield corresponding amides, carboxylic acids and ammonia. The nitrile-degrading abilities of these strains were investigated. The removal rates for the nitrile were nearly 100%, after these bacteria were grown in medium containing 10000 ppm of aceto-, propio-, or butyronitrile at 28 ℃ for 24h. When the reaction mkture consisting of 5000 ppm of above mentioned nitriles or acrylonitrile and 20g (dry cell) /L resting cells of the two strains in 0.06mol/L phosphate buffer (pH7.5) was incubated separately at 25 ℃ with moderate shaking for 15 or 45 min, the nitrile could be degraded completely. The optimum growth conditions for C.hoffmanii and A.flavescens were studied as well.     

强氧化自由基杀灭压载水微生物的模拟试验研究

在强电离电场作用下,H2O、O2分子发生电离、分解电离和电荷交换反应,在分子层次上加工成高浓度羟基溶液。试验是在每小时处理2t压载水的试验系统进行的。把羟基溶液加入压载水输送管道内,仅距加入点4m长度地方取样检测,当压载水的羟基比值浓度达到0 63mg/L时,原生动物、单胞藻、细菌浓度分别从4 4×104/mL、6 0×104/mL、1 9×105/mL均减少到低于检测方法的最低限;剩余羟基药剂分解成H2O、O2等。从试验数据表明,羟基溶液是治理压载水有效、廉价、无残留物的创新方法。