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1.
Objective To investigate the nitrifying characteristics of both suspended- and attachedbiomass in a hybrid bioreactor. Methods The hybrid biological reactor was developed by introducing porous ceramic particles into the reactor to provide the surface for biomass attachment.Microorganisms immobilized on the ceramics were observed using scanning electron microscopy (SEM). All chemical analyses were performed in accordance with standard methods. Results The suspended- and attached-biomass had approximately the same nitrification activity. The nitrifying kinetic was independent of the initial biomass concentration, and the attached-biomass had a stronger ability to resist the nitrification inhibitor. Conclusion The attached biomass is superior to suspended-biomass for nitrifying wastewater, especially that containing toxic organic compounds. The hybrid biological reactor consisting of suspended- and attached-biomass is advantageous in such cases.  相似文献   

2.
Objective To study the possibility of removing nitrogen, phosphorus, and organic pollutants using seeding type immobilized microorganisms. Methods Lakes P and M in Wuhan were chosen as the objects to study the removal of nitrogen, phosphorus, and organic pollutants with the seeding type immobilized microorganisms. Correlations between the quantity of heterotrophic bacteria and the total nitrogen (TN), total phosphorus (TP), and total organic carbon (TOC) in the two lakes were studied. The dominant bacteria were detected, inoculated to the sludge and acclimated by increasing nitrogen, phosphorus and decreasing carbon source in an intermittent, time-controlled and fixed-quantity way. The bacteria were then used to prepare the seeding type immobilized microorganisms, selecting diatomite as the adsorbent cartier. The ability and influence factors of removing nitrogen, phosphorus, and organic pollutant from water samples by the seeding type immobilized microorganisms were studied. Results The coefficients of the heterotrophic bacterial quantity correlated with TOC, TP, and TN were 0.9143, 0.8229, 0.7954 in Lake P and 0.9168, 0.7187, 0.6022 in Lake M. Ten strains of dominant heterotrophic bacteria belonging to Pseudomonas, Coccus, Aeromonas, Bacillus, and Enterobateriaceae, separately, were isolated. The appropriate conditions for the seeding type immobilized microorgansims in purifying the water sample were exposure time=24 h, pH=7.0-8.0, and quantity of the immobilized microorganisms=0.75-1g/50 mL. The removal rates of TOC, TP, and TN under the above conditions were 80.2%, 81.6%, and 86.8%, respectively. Conclusion The amount of heterotrophic bacteria in the two lakes was correlated with TOC, TP, and TN. These bacteria could be acclimatized and prepared for the immobilized microorganisms which could effectively remove nitrogen, phosphorus, and mixed organic pollutants in the water sample.  相似文献   

3.
Objective To purify a low-temperature hydroxylamine oxidase(HAO) from a heterotrophic nitrifying bacterium Acinetobacter sp.Y16 and investigate the enzyme property.Methods A HAO was purified by an anion-exchange and gel-filtration chromatography from strain Y16.The purity and molecular mass were determined by RP-HPLC and SDS-PAGE.The HAO activity was detected by monitoring the reduction of potassium ferricyanide using hydroxylamine as substrate and ferricyanide as electron acceptor.The partial amino acid sequence was determined by mass spectrometry.Results The low-temperature HAO with a molecular mass of 61 kDa was purified from strain Y16 by an anion-exchange and gel-filtration chromatography.The enzyme exhibited an ability to oxidize hydroxylamine in wide temperature range(4-40 ℃) in vitro using hydroxylamine as substrate and ferricyanide as electron acceptor.It was stable in the temperature range of 4 to 15 ℃ and pH range of6.0 to 8.5 with less than 30%change in its activity.The optimal temperature and pH were 15 ℃ and 7.5,respectively.Three peptides were determined by mass spectrometry which were shown to be not identical to other reported HAOs.Conclusion This is the first study to purify a low-temperature HAO from a heterotrophic nitrifier Acinetobacter sp.It differs from other reported HAOs in molecular mass and enzyme properties.The findings of the present study have suggested that the strain Y16 passes through a hydroxylamine-oxidizing process catalyzed by a low-temperature HAO for ammonium removal.  相似文献   

4.
Objective In order to use facultative gut bacteria as an alternate to animals for the initial gastrointestinal toxicity screening of heavy metals, a comparative study on rat intestinal epithelial cells and resident gut bacteria was undertaken. Methods in vitro growth rate of four gut bacteria, dehydrogenase (DHA) and esterase (EA) activity test, intestinal epithelial and bacterial cell membrane enzymes and in situ effect of arsenite were analysed. Results Growth profile of mixed resident population of gut bacteria and pure isolates of Escherichia coli, Pseudomonas sp., Lactobacillus sp., and Staphylococcus sp. revealed an arsenite (2-20 ppm) concentration-dependent inhibition. The viability pattern of epithelial cells also showed similar changes. DHA and EA tests revealed significant inhibition (40%-72%) with arsenite exposure of 5 and 10 ppm in isolated gut bacteria and epithelial cells. Decrease in membrane alkaline phosphatase and Ca^2+-Mg^2+-ATPase activities was in the range of 33%-55% in four bacteria at the arsenite exposure of 10 ppm, whereas it was 60%-65% in intestinal epithelial villus cells, in situ incubation of arsenite using intestinal loops also showed more or less similar changes in membrane enzymes of resident gut bacterial population and epithelial cells. Conclusion The results indicate that facultative gut bacteria can be used as suitable in vitro model for the preliminary screening of arsenical gastrointestinal cytotoxic effects.  相似文献   

5.
Objective To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant.Methods Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria.Flocculating activity was used as a measure of the flocculating capability of the bioflocculant.Results A novel bioflocculant-producing bacterium was isolated,which was identified to belong to genus Aeromonas and named as Aeromonas sp.N11.Flocculating activity increased in the presence of K ,Na ,or Ca2 .The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges,and optimum pHs for it were 3.0,4.0,and 5.0 with 1 mmol/L K ,Ca ,and Na present,respectively.The highest flocculating activities for soil suspension were observed at pH 8.0.The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mg·L-1,and its activity in kaolin suspension was decreased by only 9.2% after heating at 100℃ for 60 min.Conclusion The bioflocculant produced by Aeromonas sp.N11 has strong flocculating activity and high stability,which affords high possibility of its practical use.  相似文献   

6.
Objective To identify the bacteria tolerating chlorinated anilines and to study the biodegradability of o-chloroaniline and its coexistent compounds. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicant. Biodegradability of chlorinated anilines was determined using domesticated complex bacteria as an inoculum by shaking-flask test. Results The complex bacteria were identified,consisting of Xanthomonas,Bacillus alcaligenes,Acinetobacter,Pseudomonas,and Actinomycetaceae nocardia. The obtained complex bacteria were more tolerant to o-chloroaniline than mixture bacteria in natural river waters. The effects of exposure concentration and inoculum size on the biodegradability of o-chloroaniline were analyzed,and the biodegradation characteristics of single o-chloroaniline and 2,4-dichloroaniline were compared with the coexistent compounds. Conclusion The biodegradation rates can be improved by decreasing concentration of compounds and increasing inoculum size of complex bacteria. When o-chloroaniline coexists with aniline,the latter is biodegraded prior to the former,and as a consequence the metabolic efficiency of o-chloroaniline is improved with the increase of aniline concentration. Meanwhile,when o-chloroaniline coexists with 2,4-dichloroaniline,the metabolic efficiency of 2,4-dichloroaniline is markedly improved.  相似文献   

7.
Objective To isolate, incubate, and identify 4-chlorophenol-degrading complex bacteria, determine the tolerance of these bacteria to phenolic derivatives and study their synergetic metabolism as well as the aboriginal microbes and co-metabolic degradation of mixed chlorophenols in river water. Methods Microbial community of complex bacteria was identified by plate culture observation techniques and Gram stain method. Bacterial growth inhibition test was used to determine the tolerance of complex bacteria to toxicants. Biodegradability of phenolic derivatives was determined by adding 4-chlorophenol-degrading bacteria in river water. Results The complex bacteria were identified as Mycopiana, Alcaligenes, Pseudomonas, and Flavobacterium. The domesticated complex bacteria were more tolerant to phenolic derivatives than the aboriginal bacteria from Qinhuai River. The biodegradability of chlorophenols, dihydroxybenzenes and nitrophenols under various aquatic conditions was determined and compared. The complex bacteria exhibited a higher metabolic efficiency on chemicals than the aboriginal microbes, and the final removal rate of phenolic derivatives was increased at least by 55% when the complex bacteria were added into river water. The metabolic relationship between dominant mixed bacteria and river bacteria was studied. Conclusion The complex bacteria domesticated by 4-chlorophenol can grow and be metabolized to take other chlorophenols, dihydroxybenzenes and nitrophenols as the sole carbon and energy source. There is a synergetic metabolism of most compounds between the aboriginal microbes in river water and the domesticated complex bacteria, 4- chlorophenol-degrading bacteria can co-metabolize various chlorophenols in fiver water.  相似文献   

8.
Objective To analyze the structure of bacteria in drinking water by molecular biological techniques, Methods DNA of bacteria in drinking water was directly extracted without culture. 16S ribosomal DNA fragments, including V-6, -7, and -8 regions, were amplified with universal primers (EUBf933CJC and EUBr1387) and analyzed by DGGE. Results DGGE indicated that amplification products could be separated, The results showed that DGGE could be used in the separation of different microbial 16SrRNA genes extracted from drinkng water. Though there were special bacteria in different water samples, the predominant bacteria were essentially the same. Three sequences of the reclaimed specific bands were obtained, and phylogenetic tree of these bands was made. Conclusion Bacterial diversity in drinking water is identified by molecular biological techniques.  相似文献   

9.

Background  Bioreactors are pivotal tools for generating mechanical stimulation in functional tissue engineering study. This study aimed to create a bioreactor that can simulate urinary bladder mechanical properties, and to investigate the effects of a mechanically stimulated culture on urothelial cells and bladder smooth muscle cells.

Methods  We designed a bioreactor to simulate the mechanical properties of bladder. A pressure-record system was used to evaluate the mechanical properties of the bioreactor by measuring the pressure in culture chambers. To test the biocompatibility of the bioreactor, viabilities of urothelial cells and smooth muscle cells cultured in the bioreactor under static and mechanically changed conditions were measured after 7-day culture. To evaluate the effect of mechanical stimulations on the vital cells, urethral cells and smooth muscle cells were cultured in the simulated mechanical conditions. After that, the viability and the distribution pattern of the cells were observed and compared with cells cultured in non-mechanical stimulated condition.

Results  The bioreactor system successfully generated waveforms similar to the intended programmed model while maintaining a cell-seeded elastic membrane between the chambers. There were no differences between viabilities of urothelial cells ((91.90±1.22)% vs. (93.14±1.78)%, P >0.05) and bladder smooth muscle cells ((93.41±1.49)% vs. (92.61±1.34)%, P >0.05). The viability of cells and tissue structure observation after cultured in simulated condition showed that mechanical stimulation was the only factor affected cells in the bioreactor and improved the arrangement of cells on silastic membrane.

Conclusions  This bioreactor can effectively simulate the physiological and mechanical properties of the bladder. Mechanical stimulation is the only factor that affected the viability of cells cultured in the bioreactor. The bioreactor can change the growth behavior of urothelial cells and bladder smooth muscle cells, resulting in the cells undergoing adaptive changes in mechanically-stimulated environment.

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10.
Inactivation and microbial regrowth of penicillin-, ampicillin-, cefalexin-, tetracycline-, chloramphenicol-, and rifampicin-resistant bacteria were studied to explore risks associated with selection and regrowth of antibiotic-resistant bacteria after PAA disinfection. The results showed that after exposure to 20 mg/L PAA for 10 min, inactivation of ampicillin-resistant bacteria reached 2.3-1og, which was significantly higher than that of total heterotrophic bacteria with a decrease of 2.0-log. In contrast, inactivation of tetracycline- resistant bacteria was significantly less efficient, reaching only 1.1-1og. Chloramphenicol-and tetracycline-resistant bacteria, as well as total heterotrophic bacteria regrew more than 10 fold compared to those in the untreated wastewater sample with 22 h stilling culture after exposure to 2 or 5 mg/L PAA as for 10 min.  相似文献   

11.
活性污泥中硝化细菌16S rDNA鉴定方法研究   总被引:3,自引:0,他引:3  
目的 以活性污泥为材料,研究其中硝化细菌的分离及16Sr DNA鉴定方法。方法 采用氨氧化细菌与亚硝酸氧化细菌富集、分离技术从武汉某啤酒厂曝气池活性污泥中分离得到2株纯培养菌株N。和Nz。分别提取2株细菌的总DNA,利用氨氧化细菌与亚硝酸氧化细菌的16Sr DNA特异性引物进行多聚酶链反应(PCR)扩增;扩增产物经2%琼脂糖凝胶电泳和Sanger末端终止法测序分析,用NCBI-Blast软件将测序结果在GenbAnk等数据库中进行同源性检索。结果 N1和N2的DNA扩增产物片断大小分别为526 bp和391 bp,测序结果经检索证实N1、N2分别与标准菌株Nitrosomonas sp、DYS317和Nitrobacter sp.R6的保守性片段有99%、100%的同源性。结论 可以判定所分离得到的N1和N2菌株分别为亚硝化单胞菌属和硝化杆菌属。  相似文献   

12.
目的在成功筛选出异养硝化细菌USTB05的基础上,本文重点在USTB05的发酵培养和活性进行了研究。结果表明,采用乙醇和氨氮分别作为碳源和氮源,发酵培养1天可以获得OD680nm38.0的高异养硝化菌生物量。培养出的菌细胞去除氨氮活性高达50mg/g/h,产生亚硝酸氮的活性达到9.6mg/g/h,在高效去除氨氮方面具有重要意义和应用价值。  相似文献   

13.
目的:从中国东海分离筛选抗菌活性微生物,确定活性菌株的分类地位。方法:随机挑选30株本室保存的分离自中国东海的细菌,利用抗大肠杆菌模型进行活性筛选。对活性菌株进行形态特征、生化特征、盐需求测试及16S rDNA序列分析,并将所测得的序列在NCBI数据库进行相似性搜索,选取其中具有代表性的序列以邻接法构建系统进化树,将菌株鉴定到属。结果:筛选出活性菌株F81612和F201721,它们的最适生长盐浓度分别为10%和7.5%,菌株形态特征、生化性质与Bacillus sp.相符,菌株F81612和F201721的16S rDNA序列分别与Bacillus subtilis和Bacillus amyloliquefaciens相似程度最大。结论:利用抗大肠杆菌模型筛选到两株产大环内酯Macrolactin S的细菌,均为中等嗜盐的海洋Bacillus sp.。  相似文献   

14.
段群欢 《海南医学》2012,23(16):124-126
目的探讨胆道感染致病菌的分布特点及药敏情况,为临床合理使用抗生素提供依据。方法 464例胆道手术患者于手术中抽取胆汁行细菌培养与药敏试验,分析其实验结果。结果 464例患者中,胆汁培养阳性114例,共培养出细菌123株,其中革兰氏阴性菌91株(74.0%),革兰氏阳性菌32株(26.0%),主要致病菌为大肠埃希菌、肠球菌、肺炎克雷伯杆菌、阴沟杆菌、铜绿假单胞菌。碳青霉烯类抗菌药物对革兰氏阴性菌敏感性较好,万古霉素对革兰氏阳性菌敏感性较好。结论胆汁培养阳性率与胆道疾病严重程度存在密切的联系。治疗胆道感染首选对大肠埃希菌耐药率低的广谱抗菌药物,必要时可加用抗革兰氏阳性菌药物。  相似文献   

15.
李皇 《右江医学》2000,28(5):365-367
目的 :了解产ESBLs细菌在我院的分离情况及其耐药性 ,以利于临床对细菌感染的监控与治疗。方法 :采用Vitek32型全自动细菌鉴定系统GNS 5 0 6药敏卡进行产ESBLs菌的检测和抗生素敏感性试验。结果 :192株大肠埃希氏菌、114株肺炎克雷伯氏菌、38株阴沟肠杆菌产ESBLs菌的检出率分别为 17.7% (34 / 192 )、16 .7% (19/ 114)、5 .3% (2 / 2 8)。 5 7株绿脓杆菌、2 4株变形杆菌、19株枸橼酸杆菌均未检出产ESBLs阳性株 ;产ESBLs菌以亚胺培南最敏感 ,其次为头孢西丁。结论 :产ESELs菌感染的治疗以亚胺培南最佳 ,其次为头孢西丁。  相似文献   

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