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目的:在脱氮副球菌PD1222中表达山梨糖脱氢酶(SDH)。方法:从质粒pMD-18T上复制氨苄西林抗性基因Ampr,从酮古龙酸菌中复制SDH基因sdh,先后酶切连接到pIND4质粒上,构建pIND4-Ampr-sdh穿梭质粒;再把pIND4-Ampr-sdh电转入大肠杆菌S17-1λpir作为供体菌,脱氮副球菌PD1222为受体菌进行双亲本接合转移;挑取壮观霉素和氨苄西林双抗平板上的接合子进行培养,菌液PCR复筛接合子,测序鉴定,通过DCIP法和非变性聚丙烯酰胺凝胶电泳法检测阳性克隆的SDH活性。结果:构建的质粒pIND4-Ampr-sdh成功转入脱氮副球菌PD1222中,SDH获得表达并检测到其蛋白活性。结论:实现了SDH在脱氮副球菌中的表达,为在脱氮副球菌中研究SDH的下游电子传递链奠定了基础。 相似文献
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为了探讨实验室筛选获得的氨氧化细菌CM-NRO14和反硝化细菌CM-NRD3联合去除市政废水中氮素的应用价值,采用了两级A/O工艺进行菌株去除废水中氮素的小试实验,最后将菌株用于废水脱氮工程中。结果表明,脱氮功能菌实现了短程硝化-反硝化,氨氮去除率在98%以上,总氮去除率在75%以上, COD (化学需氧量)去除率大于90%,出水各项指标均低于城镇污水处理厂污染物排放一级(A)标准。脱氮功能菌在去除市政废水中氮素方面有很高的应用价值,可用于城镇污水处理厂提标改造等。 相似文献
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从沈阳市南部污水处理厂活性污泥中分离获得同时具备异养硝化和好氧反硝化能力的新型菌株,研究其脱氮特性,为改善污水厂的脱氮处理工艺奠定基础。对菌株进行形态学观察和16S rRNA基因鉴定;分别以NH4Cl、NaNO2、KNO3为唯一氮源探究菌株的脱氮能力;以碳源、C/N比、pH值、温度、转速、接种量(V∶V)等因素对菌株脱氮效果的影响进行研究。获得一株新型异养硝化-好氧反硝化菌株,经16S rRNA基因序列比对为副球菌属(Paracoccus),命名为Paracoccus sp. QD-19。菌株对初始氨氮浓度在300 mg/L以下的低浓度氨氮去除率能够达到100%,去除速率为8.707 mg/(L·h)且在脱氮过程中几乎没有亚硝态氮和硝态氮的积累。以亚硝态氮和硝态氮作为唯一氮源时,对此两种氮源的去除率36 h内均能达到99%,去除速率分别为4.944和5.666mg/(L·h)。确定了去除氨氮的最佳脱氮条件:琥珀酸钠为碳源,C/N比为10,pH值为7,接种量(V:V)为1%,温度为30℃,转速为140 r/min。菌株Pa... 相似文献
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脱氮是大部分污水处理系统中不可缺少的一环。由于具有经济高效、工艺简单和无二次污染等显著优势,生物脱氮工艺在最近数十年中备受关注。根据脱氮微生物的生理特性和脱氮机制不同,文中分类综述了近年来生物脱氮工艺的研究进展,重点对比分析了硝化菌、反硝化菌和厌氧氨氧化菌以及以这些菌为基础的不同生物脱氮工艺的优缺点,为复杂污水环境的脱氮工艺选择提供参考。基于微生物脱氮机制,通过合成生物学技术开发高效脱氮菌株,结合不同工艺优点并应用自动化模拟最佳条件,从而建立经济高效的脱氮工艺将是未来发展的重要方向。 相似文献
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Cd1-型亚硝酸盐还原酶脱氮工程菌的构建与表达 总被引:1,自引:0,他引:1
目的用基因工程技术将铜绿假单胞菌PAO1中nirS基因定向克隆至表达载体pQE-30上,使nirS基因得到高效表达。方法根据GenBank公布的nirS碱基序列和表达载体pQE-30的多克隆位点设计引物,以铜绿假单胞菌PAO1的基因组DNA为模板,应用PCR技术扩增目的片段nirS;之后经过BamH I和HindⅢ双酶切,定向克隆到pQE-30上,化学转化DH5α,构建含有重组质粒的转化子pQE30-nirS-DH5α;经酶切和测序鉴定,扩增产物的碱基序列与GenBank公布的序列完全吻合,再将重组质粒pQE30-nirS转化表达菌株SG13009构建脱氮基因工程菌pQE30-nirS-SG-13009(PNS)。最后用SDS-PAGE(IPTG浓度:0.05mmol/L;诱导温度:25℃;诱导时间:2~3h)和His-tag in-gel Stain鉴定cd1-型亚硝酸盐还原酶的分子量与特异性。结果构建了高效表达cd1-型亚硝酸盐还原酶的脱氮基因工程菌PNS。结论Cd1-型亚硝酸盐还原酶能够在脱氮基因工程菌PNS中得到正确和高效的表达。 相似文献
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对捷径生物脱氮的机理、运行条件、实验研究及工业应用作了简单的综述和讨论,并指出了捷径生物脱氮技术的特点及应用前景. 相似文献
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Paul A. Nauyalis Michael S. Hindahl Brian J. Wilkinson 《Biochimica et Biophysica Acta (BBA)/General Subjects》1985,840(3):297-308
Sucrose density gradient centrifugation of Paracoccus denitrificans strains ATCC 13543 and ATCC 17741 cell envelopes plus poly-β-hydroxybutyrate, isolated from organisms broken using a French pressure cell, revealed three bands of densities: I, 1.16 g/ml; II, 1.19 g/ml; III, 1.24 g/ml. On the basis of chemical and enzymatic assays and sodium dodecyl sulfate-polyacrylamide gel electrophoresis the bands were identified as: I, cytoplasmic membrane; II, poly-β-hydroxybutyrate; III, outer membrane plus poly-β-hydroxybutyrate. Poly-β-hydroxybutyrate was removed by increased low-speed centrifugation before deposition of cell envelopes. Density gradient centrifugation of cell envelopes gave a simple pattern of two bands, cytoplasmic and outer membranes. In both strains outer membranes showed a broad protein band at Mr 70 000–83 000 upon SDS-polyacrylamide gel electrophoresis of samples solubilized at 25°C, which was not present in samples solubilized at 100°C, where a single major band was present of Mr 32 000 in strain ATCC 13543 and 35 000 in strain ATCC 17741. The major outer membrane protein stained positively for lipid in both strains, as did an Mr 70 000 protein, which was the second major protein in strain ATCC 17741. The second major outer membrane protein of stain ATCC 13543 had an Mr of 20 000 in unheated samples but 23 000 in heated samples. This protein was not present in strain ATCC 17741. Quantitative data on the polar lipid compositions of cell envelope fractions are presented. 相似文献
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The replicator region of a low-copy-number plasmid, pALC1, of Paracoccus alcaliphilus JCM 7364 was cloned in a form of the minireplicon pALC100 (3.6 kb). The host range of the minireplicon embraces several species of genus Paracoccus, as well as Agrobacterium tumefaciens, Rhizobium leguminosarum, and Rhodobacter sphaeroides (all belonging to alpha-Proteobacteria), but not Escherichia coli. The complete nucleotide sequence of the replicator region (2276 bp) revealed the presence of one complete open reading frame coding for the 28.4-kDa protein (RepA) with similarity to replication proteins of plasmid pSW500 of Erwinia stewartii and pVS1 of Pseudomonas fluorescens. The iteron-like region was identified upstream of the repA gene and consisted of two clusters of repeated sequences (17 bp long) separated by a putative DnaA box. Analysis of the predicted amino acid sequence of two adjacent incomplete ORFs suggests the localization of repA between genes involved in conjugation (traG) and partitioning (parA) within the pALC1 genome. 相似文献
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A study is presented on the EPR characteristics of the paramagnetic groups in the respiratory chain present in membrane particles of Paracoccus denitrificans, the respiratory system of which is very similar to that in submitochondrial particles from beef heart. All paramagnetic prosthetic groups of the mitochondrial system are also found in the bacterial plasma membrane. Their properties suggest that the respiratory groups are embedded in very similar protein environments in the two systems. 相似文献
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Sofia Andersson Gunnel Dalhammar Carl Johan Land Gunaratna Kuttuva Rajarao 《Applied microbiology and biotechnology》2009,82(3):535-543
Extracellular polymeric substances (EPS) play an important role in the formation and activity of biofilms in wastewater treatment
(WWT). The EPS of the denitrifying biomarker Comamonas denitrificans strain 110, produced in different culture media and growth modes, were characterized. The EPS mainly contained protein (3–37%),
nucleic acids (9–50%), and carbohydrates (3–21%). The extracellular DNA was found to be important for initial biofilm formation
since biofilm, but not planktonic growth, was inhibited in the presence of DNase. The polysaccharide fraction appeared to
consist of at least two distinct polymers, one branched fraction (A) made up of glucose and mannose with a molecular weight
around 100 kDa. The other fraction (B) was larger and consisted of ribose, mannose, glucose, rhamnose, arabinose, galactose,
and N-acetylglucosamine. Fraction B polysaccharides were mainly found in capsular EPS which was the dominant type in biofilms and
agar-grown colonies. Fraction A was abundant in the released EPS, the dominant type in planktonic cultures. Biofilm and agar-grown
EPS displayed similar overall properties while planktonic EPS showed clear compositional disparity. This study presents results
on the physiology of a key WWT organism, which may be useful in the future development of improved biofilm techniques for
WWT purposes. 相似文献
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【背景】目前缺少具有高效脱氮能力、较高生物安全性、能处理高碱含氮污水的好氧反硝化菌株,难以使用生物方法处理高碱性的工业、养殖废水。【目的】对前期于佛山市一水产养殖池塘底泥中分离得到的耐碱高效好氧反硝化细菌ZY-3进行研究,期望获得一株能用于不同酸碱环境脱氮的高效、安全的好氧反硝化细菌。【方法】通过形态学、生理生化试验及16S rRNA基因序列分析方法对菌株种属进行鉴定,采用抗生素试验及斑马鱼攻毒试验进行菌株的环境生物安全性评估,利用3种含不同氮素的含氮模拟废水进行脱氮能力的测定。【结果】确定ZY-3为假单胞菌属变形假单胞菌(Pseudomonas plecoglossicida),其对多种临床常用抗生素敏感,对水生生物的毒性低,该菌株在高浓度含氮模拟废水中以28℃、180 r/min振荡培养时,其对数期出现在4—12 h,在12 h时NH4+-N、NO3--N和NO2--N的去除率分别达到94.87%、81.44%和98.02%,其pH耐受范围为6.0—10.0。【结论】得到一株安全、高效、具有广泛pH适应范围的耐碱好氧反硝化细菌P. plecoglossicida ZY-3,其在有氧条件下对3种氮素(NH4+-N、NO3–-N、NO2–-N)具有快速去除能力。 相似文献
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Tonči Rezić Božidar Šantek Srđan Novak Vladimir Marić 《World journal of microbiology & biotechnology》2007,23(7):987-996
In this work, the heterotrophic cultivation of bacterium Paracoccus denitrificans has been studied in a horizontal rotating tubular bioreactor (HRTB). After development of a microbial biofilm on the inner
surface of the HRTB, conditions for one-step removal of acetate and ammonium ion were created. The effect of bioreactor process
parameters [medium inflow rate (F) and bioreactor rotation speed (n)] on the bioprocess dynamics in the HRTB was studied. Nitrite and nitrogen oxides (NO and N2O) were detected as intermediates of ammonium ion degradation. The biofilm thickness and the nitrite concentration were gradually
reduced with increase of bioreactor rotation speed when the medium inflow rate was in the range of 0.5–1.5 l h−1. Further increase of inflow rate (2.0–2.5 l h−1) did not have a significant effect on the biofilm thickness and nitrite concentration along the HRTB. Complete acetate consumption
was observed when the inflow rate was in the range of 0.5–1.5 l h−1 at all bioreactor rotation speeds. Significant pH gradient (cca 1 pH unit) along the HRTB was only observed at the highest
inflow rate (2.5 l h−1). The results have clearly shown that acetate and ammonium ion removal by P. denitificans can be successfully conducted in a HRTB as a one-step process. 相似文献