一株好氧反硝化细菌的分离鉴定及反硝化特性研究

通过对采集水样进行富集培养,利用溴百里酚蓝( BTB)选择性培养基初筛和活性测定复筛得到一株好氧反硝化细菌N22’,发现该菌在好氧条件下能有效去除培养液中的NO3--N.硝酸盐氮初始浓度为125 mg/L,培养40h后硝酸盐氮去除率达86.39％;扫描电镜照片显示,菌株N22’为短杆菌,无鞭毛,大小约为(0.75-1.25)μm×(0.5-0.75) μm范围内,菌落表面呈乳白色.通过形态、生理生化特征及16S rRNA基因序列分析,初步判断菌株N22’为不动杆菌属Acinetobacter sp..反硝化性能测试结果表明,该菌反硝化作用的最适温度为25-30℃,pH值7.0.     

基于响应面法对一株好氧反硝化菌脱氮效能优化

【目的】水体富营养化是当今我国水环境面临的重大水域环境问题,氮素超标排放是主要的引发因素之一。好氧反硝化菌构建同步硝化反硝化工艺比传统脱氮工艺优势更大。获得高效的好氧反硝化菌株并通过生长因子优化使脱氮效率达到最高。【方法】经过序批式生物反应器(Sequencing batch reactor,SBR)的定向驯化,筛选获得高效好氧反硝化菌株,采用响应面法优化好氧反硝化过程影响总氮去除效率的关键因子(碳氮、溶解氧、pH、温度)。【结果】从运行稳定的SBR反应器中定向筛选高效好氧反硝化菌株Pseudomonas T13,采用响应面法对碳氮比、pH和溶解氧关键因子综合优化获得在18 h内最高硝酸盐去除率95%,总氮去除率90%。该菌株的高效反硝化效果的适宜温度范围为25?30 °C;最适pH为中性偏碱;适宜的COD/NO3?-N为4:1以上;最佳溶解氧浓度在2.5 mg/L。【结论】从长期稳定运行的SBR反应器中筛选获得一株高效好氧反硝化菌Pseudomonas T13,硝酸盐还原酶比例占脱氮酶基因的30%以上,通过运行条件优化获得硝氮去除率达到90%以上,对强化废水脱氮工艺具有良好应用价值。     

一株好氧反硝化菌的分离及特性研究

从土壤中分离得到一株好氧反硝化细菌CY1, 该菌株在厌氧和好氧条件下均具有反硝化能力。硝酸盐氮初始浓度为137.25 mg/L, 30 h内硝酸盐氮去除率分别为99.98%(厌氧)和60.16%(好氧)。通过形态学特征、生理生化特性及16S rDNA同源性比较对菌株CY1进行鉴定, 初步判断CY1为泛养副球菌(Paracoccus pantotrophus)。     

好氧反硝化菌代谢机制及其与重金属相互作用的代谢特征

好氧反硝化是在好氧条件下将NO3--N最终转化为N2的过程.好氧反硝化菌不仅表现出优秀的脱氮性能,可在许多极端条件下生存,还拥有多种重金属耐受性.本文总结了不同重金属Cr(Ⅵ)、Cu(Ⅱ)和Cd(Ⅱ)对好氧反硝化菌脱氮效率的影响,同时整理了好氧反硝化菌对不同重金属的耐受或去除机制.分析了好氧反硝化菌在工业废水处理中的应...     

好氧反硝化菌的筛选及其脱氮除磷性质的研究

利用富集培养基, 从用生活污水驯化后的活性污泥中筛选得到一株具有好氧反硝化兼具除磷功能的细菌。通过形态学及生理生化指标鉴定其为假单胞菌属。利用此好氧反硝化菌处理模拟废水及生活废水, 通过监测总氮、无机磷及CODcr变化确定在C/N摩尔比为3:1、接种量为10%、pH 6.8、30°C条件下处理2 d, 该菌株脱氮、除磷及去除有机物的效果最佳, 活性污泥经此好氧反硝化菌强化后, 对生活废水的处理能力得到明显提升。     

好氧反硝化微生物学机理与应用研究进展

近年来,关于好氧反硝化过程的研究主要集中在三个方面:分别是好氧反硝化菌株的分离和脱氮性能表征,好氧反硝化微生物的应用潜力分析,以及好氧反硝化过程的机理研究。好氧反硝化菌株分布范围广泛,可从多种环境中分离得到,种属以Pseudomonas sp.、Alcaligenes sp.和Paracoccus sp.为主。好氧反硝化菌株及菌群在实验室条件下表现出优良的耐冷、耐盐特性,并具有可降解毒性有机物及N_2O减排的潜力。关于好氧反硝化过程的机理研究表明,虽然硝酸盐作为电子受体的竞争力比氧气弱,但反硝化作为辅助电子传递途径,可提高产能效率,防止NAD(P)H的过量积累。因此,硝酸盐可与氧气同时参与微生物的新陈代谢,即发生好氧反硝化现象。未来除了继续分离更新更好的好氧反硝化菌株外,应加强对好氧反硝化机理及实际生物强化方面的研究。     

好氧反硝化菌Defluvibacter lusatiensis str.DN7的分离鉴定和异养硝化性能

从稳定运行处理竹子加工废水的生物接触氧化反应器中分离得到一株好氧反硝化菌DN7,其72 h NO3-降解率达99.4％.细胞显微镜观察显示,菌株为革兰氏阴性小杆菌,大小为0.5 μm×1.5 μm,菌落为乳白色.通过生理生化特性及16S rDNA同源性分析,初步推断该菌株为根瘤菌中的Defluvibacter lusatiensis str.碳源、C/N、硝酸盐初始浓度、溶解氧(DO)、pH对DN7反硝化性能影响的结果表明:菌株对柠檬酸钠、葡萄糖等小分子有机物的利用较好;C/N为9时,脱氮率达99.0％;硝酸盐浓度低于138.48 mg·L-1情况下,DN7脱氮率在96％以上,且亚硝酸盐浓度均在1.0mg·L-1以下;菌株DN7对DO不敏感,中性偏碱性环境有利于DN7反硝化反应的进行;DN7具有良好的异养硝化性能,72 h铵氮降解率达84.7％.     

不同氮源下好氧反硝化菌Defluvibacter lusatiensis str.DN7的脱氮特性

研究了不同氮源下好氧反硝化菌Defluvibacter lusatiensis str.DN7的脱氮特性。结果表明:菌株均能以硝酸盐和亚硝酸盐为唯一氮源进行好氧反硝化作用。反应4 h,NO-3-N和NO-2-N的去除率分别达83.35%和85.72%。亚硝酸盐完全还原比硝酸盐提前42 h。硝酸盐还原过程中基本无亚硝酸盐积累,而亚硝酸盐还原过程中则检测到明显的硝酸盐积累,反应4 h,NO-3-N积累量达到21.83 mg/L。培养液中同时存在硝酸盐和亚硝酸盐时,菌株优先选择硝酸盐作电子受体。亚硝酸盐共存对硝酸盐还原无显著影响,但培养液中残留的NO-2-N随亚硝酸盐比例上升而增加,当亚硝酸盐比例从10%升至50%时,NO-2-N残留量由3.38 mg/L增至7.60 mg/L。少量硝酸盐的加入对亚硝酸盐的还原产生抑制作用。当硝酸盐比例为10%时,72 h NO-2-N的去除率仅为74.79%,远低于以亚硝酸盐为唯一氮源情况(去除率100%)。以氨氮为唯一氮源时,菌株同时进行异养硝化和好氧反硝化反应,72 h,NH+4-N去除率达85.66%,且基本无硝酸盐或亚硝酸盐积累。少量氨氮共存(氨氮比例<30%)有利于促进菌株的好氧反硝化作用,反之亦然。     

好氧反硝化细菌及其在微污染水源水修复中的应用研究进展

相比于氨氮,天然水体中的硝酸盐氮通常更稳定,导致更难将其从水中去除。由于好氧反硝化可以在有氧环境下进行反硝化作用去除硝酸盐氮,该过程对含有较高溶解氧的天然水体中硝酸盐氮处理有重要作用。本文综述了好氧反硝化菌的分离纯化现状、微生物代谢机制和环境影响因子,并介绍了功能菌群在微污染饮用水源水生物修复的应用研究进展。与一般的厌氧反硝化类似,好氧反硝化菌的种属分布较广,常见的如假单胞菌属(Pseudomoas)、产碱杆菌属(Alcaligenes)、副球菌属(Paracoccus)和芽孢杆菌属(Bacillus)等所属部分微生物均有好氧反硝化能力。大部分好氧反硝化菌株在最佳生长条件下(25–37℃、溶解氧浓度为3–5mg/L、pH为7–8、碳氮比为5–10)具有高效的脱氮效率。但目前好氧反硝化作用在微污染饮用水源水的生物修复方面的应用仍有着脱氮性能不稳定、菌剂流失等不足。此外,目前较少相关中试及实际工程应用的研究,需要进一步的深入探究。     

一株海水异养硝化-好氧反硝化菌系统发育及脱氮特性

【目的】确定一株分离自海水的异养硝化-好氧反硝化菌的系统发育地位并探索其脱氮特性和机理,以期为解释异养硝化-好氧反硝化机理以及改进海水养殖及废水的生物脱氮工艺提供理论依据。【方法】通过形态观察、生理生化实验和16S rRNA基因序列分析,鉴定该菌株;通过测定菌株在不同无机氮源降解测试液中的生长和脱氮效率,分析其异养硝化和好氧反硝化性能。【结果】经鉴定该菌株属于盐单胞菌属(Halomonas);最适生长条件为盐度3%、pH 8.5、温度28℃、碳氮比10:1,在盐度为15%的培养液中仍能生长;可以同时去除氨氮、亚硝酸氮和硝酸氮,24 h时对NH4+-N、NO2--N、和NO3--N的去除率可分别达到98.29%、99.07%、96.48%,3种形态无机氮同时存在时,会优先利用NH4+-N,且总无机氮去除率较单一存在时更高,说明该菌株可实现同步硝化反硝化。【结论】该分离自海水的异养硝化-好氧反硝化菌属于盐单胞菌属(Halomonas),在高盐环境中仍能生长,同时具有高效的异养硝化和好氧反硝化能力,能够独立完成脱氮的全部过程。     

Enhanced denitrifying phosphorous removal in a novel anaerobic/aerobic/anoxic (AOA) process with the diversion of internal carbon source

A novel anaerobic/aerobic/anoxic (AOA) process is proposed to realize denitrifying phosphorous removal in this study, and the characteristic of the AOA process is transferring part of the anaerobic mixed liquor to the post-anoxic zone for providing the carbon source needed for denitrification. The AOA process was operated for 3 months, and the average removal efficiencies of NH4+-N, TN and PO4(3-)-P were 93.0±3.1%, 70.3±2.9% and 87.3±11.8%, respectively. A mass balance analysis indicated that 0.49±0.02 g VSS(-1) d(-1) of PO4(3-)-P and 0.23±0.04 g VSS(-1) d(-1) of NO3--N were simultaneously removed in the anoxic zone, and it is speculated that denitrifying phosphorous removal occurred in the AOA process. Furthermore, 0.24±0.06 g VSS(-1) d(-1) of TN was removed in the aerobic zone via simultaneous nitrification and denitrification (SND). The results demonstrate that the multi-zone structure of the AOA process favors the enhancement of denitrifying phosphorous removal and SND for municipal wastewater treatment.     

Pseudomonas alcaliphila AD-28的脱氮性能及其关键酶活性

【背景】异养硝化-好氧反硝化菌由于能够同时实现硝化反硝化作用而备受关注,但由于菌的种类不同,其脱氮途径不尽相同,研究菌株脱氮关键酶的种类及其活性可以推测菌株的脱氮途径,从而为菌株在生产上的应用提供技术支撑。【目的】研究Pseudomonas alcaliphila AD-28的脱氮性能及其关键酶的活性,为菌株脱氮分子机理研究奠定基础。【方法】以柠檬酸钠为碳源,以硫酸铵、亚硝酸钠、硝酸钾为氮源,研究菌株AD-28的脱氮性能并检测其关键酶氨单加氧酶(AMO)、羟胺氧化还原酶(HAO)、亚硝酸盐还原酶(NIR)、硝酸盐还原酶(NAR)的酶活性。【结果】菌株AD-28培养24h的菌密度(OD600)可达1.971,对初始浓度为18.85mg/L的氨氮、26.13mg/L的硝酸盐氮、19.47mg/L的亚硝酸盐氮、66.11 mg/L的总氮去除率均达到96%以上;关键酶AMO、HAO、NIR和NAR的比活力分别为0.028、0.003、0.011、0.027 U/mg。【结论】Pseudomonas alcaliphila AD-28能同时进行异养硝化-好养反硝化作用,该菌在AMO作用下将NH4+-N氧化为羟胺,然后由HAO氧化为NO2--N,NO2--N和NO3--N在NIR、NAR等酶的催化作用下脱氮。     

An effective way to select slow-growing nitrifying bacteria by providing a dynamic environment

In this study, two laboratory scale sequencing batch reactors (SBRs) were conducted to study the stability of aerobic granules. The strategy was involved in stepwise increase in ammonium (NH4⁺-N) concentration in the influent. Results showed that the activity of nitrifying bacteria and diameter of the aerobic granules significantly increased with gradually increasing NH4⁺-N, which reached persistently new balances by homeostasis. As a result, the stability of aerobic granules was remarkably enhanced. The value of sludge volume index (SVI) was below 25 ml/g, the mean settling velocity was excellent up to 107 m/h. The NH4⁺-N removal efficiency averaged above 99% and total nitrogen (TN) removal was greatly enhanced and could reach 68%. Besides dissolved oxygen, the granules size was also a dominant factor to influence denitrification, which could gradually increase in variable conditions through homeostasis. Stable, dense and well-settling nitrifying granules can be developed for simultaneous nitrification and denitrification removal.     

基于好氧反硝化及反硝化聚磷菌强化的低温低碳氮比生活污水生物处理中试研究

【背景】低碳氮比生活污水很难达标处理,多级A/O工艺、生物强化技术及生物膜技术的有机结合可有效解决这一问题。【目的】开发出一种泥膜共生多级A/O工艺并进行中试研究,驯化出高效脱氮除磷菌剂并对系统进行生物强化。【方法】通过测定中试设备出水及污水处理厂出水化学需氧量(Chemical oxygen demand,COD)、氨氮(NH_4~+-N)、硝氮(NO_3~--N)、总氮(Total nitrogen,TN)、总磷(Total phosphorus,TP)对比分析两种工艺的污染物去除效能,利用高通量测序技术对比生物强化技术对系统微生物群落结构的影响。【结果】中试设备对COD、NH_4~+-N、NO_3~--N、TN、TP的去除效果均优于污水处理厂的处理工艺;驯化的低温好氧反硝化菌TN去除率最大值可达84.21%,驯化的低温反硝化聚磷菌群对磷的去除率最高可达85.75%;利用驯化菌群对中试设备进行生物强化后较好地改善了系统NH_4~+-N、NO_3~--N、TN、TP的去除效果;经生物强化后,具有好氧反硝化和反硝化聚磷功能的Pseudomonas菌群明显增多。【结论】泥膜共生多级A/O工艺对于低碳氮比生活污水的处理具有很好的效果,利用生物强化技术可有效提高低温条件下系统污染物去除效能。     

降氨除臭芽孢杆菌的筛选鉴定及其氮素迁移过程

【目的】分离和鉴定一株高效降氨除臭芽孢杆菌,并研究其氮素迁移过程。【方法】采用自行设计的筛选平台,根据菌落形态、生理生化特征及16S rRNA基因序列的系统进化树分析进行菌株鉴定;在好氧和厌氧条件下,以NH4+-N为唯一氮源,通过检测NH4+-N、NO2?-N、NO3?-N和产生的气体浓度,明确菌株在降氨过程中氮素的迁移过程及特点。【结果】筛选出一株高效降氨除臭芽孢杆菌,经生化与分子鉴定为凝结芽孢杆菌;其在好氧条件下将NH4+-N降解为NO3?-N,降解率为98%;同时少量NO3?-N经好氧反硝化作用还原为N2;在厌氧条件下进行了硝化作用,但NH4+-N降解率仅为23.7%,且反硝化过程不明显。【结论】筛选得到的高效降氨除臭凝结芽孢杆菌在好氧和厌氧条件下皆具有异养硝化作用,但厌氧条件下反硝化作用不显著,好氧反硝化作用产生的含氮气体为氮气,其在农业和环保领域具有巨大的产业化潜力。     

Redox control bioreactor: a unique biological water processor

The redox control bioreactor (RCB) is a new hollow fiber membrane bioreactor (HFMBR) design in which oxygen and hydrogen gases are provided simultaneously through separate arrays of juxtaposed hollow fiber (HF) membranes. This study applied the RCB for completely autotrophic conversion of ammonia to N(2) through nitrification with O(2) and denitrification using hydrogen as an electron donor (i.e., autohydrogentrophic denitrification). The hypothesis of this research was that efficient biofilm utilization of O(2) and H(2) at respective HFs would limit transport of these gases to bulk fluid, thereby enabling completely autotrophic ammonia conversion to N(2) through the co-occurrence of ammonia oxidation (O(2)-HF biofilms) and autohydrogenotrophic denitrification (H(2)-HF biofilms). A prototype RCB was fabricated and operated for 215 days on a synthetic, organic-free feedstream containing 217 mg L(-1) NH(4)(+)-N. When O(2) and H(2) were simultaneously supplied, the RCB achieved a steady NH(4)(+)-N removal flux of 5.8 g m(-2) day(-1) normalized to O(2)-HF surface area with a concomitant removal flux of 4.4 g m(-2) day(-1) (NO(3)(-))+NO(2)(-))-N based on H(2)-HF surface area. The significance of H(2) supply was confirmed by an increase in effluent NO(3)(-)-N when H(2) supply was discontinued and a decline in NO(3)(-)-N when H(2) supply was restarted. Increases in H(2) pressure caused decreased ammonia utilization, suggesting that excess H(2) interfered with nitrification. Microprobe profiling across radial transects revealed significant gradients in dissolved O(2) on spatial scales of 1 mm or less. Physiological and molecular analysis of biofilms confirmed that structurally and functionally distinct biofilms developed on adjacent, juxtaposed fibers.     

In situ simultaneous organics and nitrogen removal from recycled landfill leachate using an anaerobic-aerobic process

An anaerobic-aerobic process including a fresh refuse landfill reactor as denitrifying reactor, a well-decomposed refuse reactor as methanogenesis reactor and an aerobic activated sludge reactor as nitrifying reactor was operated by leachate recirculation to remove organic and nitrogen simultaneously. The results indicated that denitrification and methanogenesis were carried out successfully in the fresh refuse and well-decomposed landfill reactors, respectively, while the nitrification of NH(4)(+)-N was performed in the aerobic reactor. The maximum organic removal rate was 1.78 kg COD/m(3)d in the well-decomposed refuse landfill reactor while the NH(4)(+)-N removal rate was 0.18 kg NH(4)(+)-N/m(3)d in the aerobic reactor. The biogas from fresh refuse reactors and well-decomposed refuse landfill reactors were consisted of mainly carbon dioxide and methane, respectively. The volume fraction of N(2) increased with the increase of NO(3)(-)-N concentration and decreased with the drop of NO(3)(-)-N concentration. The denitrifying bacteria mustered mainly in middle layer and the denitrifying bacteria population had a good correlation with NO(3)(-)-N concentration.     

Nitrosospira spp. can produce nitrous oxide via a nitrifier denitrification pathway

Nitrous oxide (N(2)O) emission from soils is a major contributor to the atmospheric loading of this potent greenhouse gas. It is thought that autotrophic ammonia oxidizing bacteria (AOB) are a significant source of soil-derived N(2)O and a denitrification pathway (i.e. reduction of NO(2) (-) to NO and N(2)O), so-called nitrifier denitrification, has been demonstrated as a N(2)O production mechanism in Nitrosomonas europaea. It is thought that Nitrosospira spp. are the dominant AOB in soil, but little information is available on their ability to produce N(2)O or on the existence of a nitrifier denitrification pathway in this lineage. This study aims to characterize N(2)O production and nitrifier denitrification in seven strains of AOB representative of clusters 0, 2 and 3 in the cultured Nitrosospira lineage. Nitrosomonas europaea ATCC 19718 and ATCC 25978 were analysed for comparison. The aerobically incubated test strains produced significant (P < 0.001) amounts of N(2)O and total N(2)O production rates ranged from 2.0 amol cell(-1) h(-1), in Nitrosospira tenuis strain NV12, to 58.0 amol cell(-1) h(-1), in N. europaea ATCC 19718. Nitrosomonas europaea ATCC 19718 was atypical in that it produced four times more N(2)O than the next highest producing strain. All AOB tested were able to carry out nitrifier denitrification under aerobic conditions, as determined by production of (15)N-N(2)O from applied (15)N-NO(2) (-). Up to 13.5% of the N(2)O produced was derived from the exogenously applied (15)N-NO(2) (-). The results suggest that nitrifier denitrification could be a universal trait in the betaproteobacterial AOB and its potential ecological significance is discussed.