污水库底泥微生物对六六六降解的研究

污水库底泥对六六六具有自然净化能力,其中微生物起着重要作用。在嫌气条件下(25—30℃)对六六六降解较快,20天可降解所加18—20ppm六六六的90％。从底泥筛选出30多株可以降解六六六的细菌,其中一株短芽孢杆菌(Bacillus brcvis)可将丙体六六六降解为间二氯苯和转化成少量甲体六六六,在25—30℃条件和增加适当营养物质、中性和微碱性以及驯化均可加速污水库底泥微生物对六六六的降解。以上结果为了解六六六在环境中的消失和利用污水库降解六六六,净化水质提供了依据。     

污水库底泥微生物对六六六降解的研究

污水库底泥对六六六具有自然净化能力,其中微生物起着重要作用。在嫌气条件下(25—30℃)对六六六降解较快,20天可降解所加18—20ppm六六六的90％。从底泥筛选出30多株可以降解六六六的细菌,其中一株短芽孢杆菌(Bacillus brcvis)可将丙体六六六降解为间二氧苯和转化成少量甲体六六六,在25—30℃条件和增加适当营养物质,中性和微碱性以及驯化均可加蓬污水库底泥微生物对六六六的降解。以上结果为了解六六六在环境中的消失和利用污水库降解六六六,净化水质提供了依据。     

静态强磁场对枯草芽胞杆菌的影响研究

目的:研究静态强磁场下微生物的生物学效应.方法:以超导磁体产生的静态强磁场为基础,枯草芽孢杆菌为模式生物,通过测定生长曲线、芽胞生成率、蛋白酶表达量、蛋白酶活力等研究静态强磁场条件下微生物性状的变化.结果:强磁场可以影响枯草芽胞杆菌的芽胞形成速率,抑制营养体的死亡;测定菌体生长过程中蛋白酶的含量以及碱性蛋白酶和中性蛋白酶的酶活力,发现磁场处理前后蛋白酶的含量没有发生显著性变化,处理组碱性蛋白酶的酶活力明显高于对照组,而中性蛋白酶酶活力则低于对照组.结论:强磁场可以延长枯草芽孢杆菌的世代周期,降低菌体死亡率,对细菌酶活性的影响因酶的种类不同而异.     

细菌麦芽糖淀粉酶在枯草芽孢杆菌中的诱导型异源表达

【目的】实现地衣芽孢杆菌麦芽糖淀粉酶在枯草芽孢杆菌中的高效异源表达,并研究该重组酶的酶学性质。【方法】克隆巨大芽孢杆菌木糖异构酶基因的启动子区域及其调控蛋白,构建一个大肠杆菌/芽孢杆菌穿梭型诱导表达质粒,使用该诱导型启动子介导麦芽糖淀粉酶编码基因,实现其在枯草芽孢杆菌中的功能表达。对重组枯草芽孢杆菌的诱导条件进行优化,提高麦芽糖淀粉酶的产量。【结果】获得了诱导表达麦芽糖淀粉酶基因的重组枯草芽孢杆菌菌株。最适诱导温度为45°C,最适诱导剂添加浓度为1%,最适添加诱导剂时间为接种培养9 h后。重组酶蛋白分子量大小为67 k D,对该酶的酶学性质研究发现,以可溶性淀粉为底物,反应生成麦芽糖和葡萄糖,其中麦芽糖含量为60.42%。重组酶最适作用温度为45°C,最适作用p H为6.5,Ca2+、Co2+、EDTA对该重组麦芽糖淀粉酶具有激活作用。【结论】通过木糖诱导表达系统可以实现麦芽糖淀粉酶在枯草芽孢杆菌中的高效诱导型表达,酶活最高可达296.64 U/m L发酵液,在工业上有着较好的应用前景。     

一株枯草芽孢杆菌的生长特性及抑藻效果研究

溶藻微生物能引起水华蓝藻的快速消亡,从而达到控制水华之目的。为了探讨枯草芽孢杆菌(Bacillus subtilis)对铜绿微囊藻(Microcystis aeruginosa)及小球藻(Chlorell)的抑制效果,在实验室条件下研究了枯草芽孢杆菌对两种藻类生长的影响、抑制藻类生长的作用方式以及发酵液处理下铜绿微囊藻丙二醛(MDA)及谷胱甘肽(GSH)含量、超氧化物歧化酶(SOD)及过氧化氢酶(CAT)活性。试验结果表明,筛选出的菌株具有较好的环境适应性和抑制藻类生长的能力,其抑制效果是通过分泌胞外物质实现的。经过枯草芽孢杆菌处理后,铜绿微囊藻的叶绿素a及藻体蛋白含量均显著低于对照组,而胞内MDA及GSH含量显著升高,SOD及CAT活性也有增高的趋势。     

巨大芽孢杆菌β-淀粉酶在枯草芽孢杆菌中诱导表达及碳代谢去阻遏

【背景】β-淀粉酶在食品和医疗领域应用广泛。目前工业上使用的β-淀粉酶主要从植物中提取,生产成本高,限制了β-淀粉酶的应用。微生物生产的β-淀粉酶尽管早有报道,但由于产酶水平低下,因而一直未能实现工业化。【目的】实现巨大芽孢杆菌β-淀粉酶在枯草芽孢杆菌中的高效诱导表达,缓解碳分解代谢物阻遏(Carbon catabolite repression,CCR)对该重组酶表达的影响,并研究其酶学性质。【方法】克隆枯草芽孢杆菌木糖诱导启动子,构建木糖诱导表达载体以介导巨大芽孢杆菌1514的β-淀粉酶编码基因amyM在枯草芽孢杆菌中的异源表达。定点突变位于amyM信号肽编码区的分解代谢物响应元件(Catabolite responsive element,CRE),降低碳源代谢对重组β-淀粉酶施加的阻遏。【结果】构建了诱导表达β-淀粉酶基因的重组枯草芽孢杆菌菌株。同义替换amyM-CRE保守碱基在不同程度上缓解了碳源所施加的CCR效应,重组酶的表达水平得到显著提高。重组酶的分子量为57 kD,水解可溶性淀粉主要生成麦芽糖和少量葡萄糖,其中麦芽糖含量为72%。该酶最适作用温度为50°C,最适反应pH为6.0。Co2+、Ca2+对重组β-淀粉酶具有激活作用。【结论】通过木糖诱导表达系统和碳代谢去阻遏实现了β-淀粉酶在枯草芽孢杆菌中的高效表达,酶活最高可达97.16 U/mL发酵液,比amyM基因来源菌巨大芽孢杆菌1514的β-淀粉酶产量提高了440倍,为β-淀粉酶发酵生产的工业化提供了支撑。     

高效羽毛降解菌株的鉴定及发酵条件的优化

通过前期研究筛选获得一株高效降解羽毛的菌株BS8,该菌株在48 h内可将完整羽毛全部降解。研究其对不同动物毛发的降解能力发现,该菌株对羽毛类硬蛋白降解效果最明显。通过形态学、生理生化特性及16S r DNA分析,结果表明该菌株为枯草芽孢杆菌(Bacillus subtilis)。对菌株的最适培养条件进行了单因素试验优化,同时将显著因素进行正交试验。试验结果表明,枯草芽孢杆菌BS8液体发酵的最适培养条件为:起始p H 8.0,发酵温度37℃,接种量2%,羽毛含量1%,转速180 r/min,摇床培养48 h。在上述条件下测得其角蛋白酶活力为23.6 U/m L,相对于优化前18.2 U/m L提高了29.7%。废弃羽毛经枯草芽孢杆菌BS8发酵酶解不仅有利于环境保护,其发酵产物可广泛用于饲料蛋白源及有机肥料。     

两株微生物菌株对阿维菌素降解性能的研究CSCD

抗生素滥用问题给环境带来严重的影响,寻求一种处理环境中残余抗生素的方法至关重要。本文采用单因素法与多因素法结合的方法,测试枯草芽孢杆菌和志贺氏菌对阿维菌素的降解性能,两株细菌表现出良好的阿维菌素降解性能。随后,利用Box-Behnken design软件对实验结果进行响应面分析,继而对阿维菌素的降解条件进行优化。枯草芽孢杆菌降解阿维菌素的优化条件为温度35.43℃、装样量57.56 mL、菌种液量3.85%,此时可达到理论最大降解率59.15%;志贺氏菌降解阿维菌素的优化条件为温度30.45℃、装样量60.24 mL、菌种液量3.56%,此时可达到理论最大降解率65.34%。结果表明,枯草芽孢杆菌及志贺氏菌是降解阿维菌素的性能优良的菌株,其响应面模型确定系数均在90%以上。因此,该模型可用于分析微生物菌株对阿维菌素的降解效果,为实际中微生物菌株降解阿维菌素提供理论依据。     

耐高温亚硝酸盐降解菌的分离、鉴定及降低雪茄烟叶亚硝胺的应用

【背景】烟草特有亚硝胺(tobacco-specific nitrosamines, TSNAs)是烟草于调制和发酵阶段产生的一类致癌物质,由烟草生物碱与氮氧化物发生亚硝化反应生成,生物碱和亚硝酸盐是TSNAs的直接前体物质。【目的】发掘适用雪茄高温发酵且显著降低TSNAs形成与积累的微生物。【方法】以TSNAs前体物质亚硝酸盐的高效降解为目标,对从雪茄烟叶分离得到的烟草源微生物菌株进行高温培养、亚硝酸盐降解及亚硝酸盐耐受能力研究,得到可于50℃高效降解亚硝酸盐及耐受高浓度亚硝酸盐的微生物菌株,将菌株应用于雪茄烟叶高温发酵35 d,对发酵前后亚硝酸盐、TSNAs、常规化学成分和中性香味成分含量进行测定,分析菌株在雪茄烟叶发酵中对TSNAs含量及烟叶品质的影响。【结果】获得了3株于50℃高效降解亚硝酸盐的菌株NY7、NY8和NY9,分别鉴定为莫海威芽孢杆菌(Bacillus mojavensis) NY7、耐盐芽孢杆菌(Bacillus halotolerans) NY8和枯草芽孢杆菌(Bacillus subtilis) NY9,其中B. halotolerans NY8亚硝酸盐降解能...     

葡萄糖醛酸木聚糖酶在枯草芽孢杆菌中的表达及发酵条件优化

为了研究葡萄糖醛酸木聚糖酶在枯草芽孢杆菌中异源表达,笔者从枯草芽孢杆菌中克隆得到带有自身信号肽的葡萄糖醛酸木聚糖酶基因,将其构建到大肠杆菌-枯草芽孢杆菌穿梭质粒中,转化入枯草芽孢杆菌WB800,得到重组菌。通过发酵条件以及培养基成分优化,重组菌中葡萄糖醛酸木聚糖酶酶活达到76.0 U/mL,约为优化前产酶量的5.4倍。葡萄糖醛酸木聚糖酶在枯草芽孢杆菌中实现高效异源表达,为其进一步的实际应用奠定了基础。     

Synchronous anaerobic and aerobic degradation of DDT by an immobilized mixed culture system

Summary For the investigation of a mixed anaerobic and aerobic degradation of xenobiotics the reductive dechlorination of 1,1,1-trichloro-2,2-bis (4-chlorophenyl)ethane (DDT) to 1,1-dichloro-2,2-bis (4-chlorophenyl)ethane (DDD) and the oxidative degradation of the DDT-conversion product 4,4-dichlorodiphenylmethane (DDM) were studied. Enrichments from digested sewage sludge led to the isolation of an Enterobacter cloacae-strain which is able to reductive dechlorination of DDT during the fermentation of lactose. From fresh sewage sludge 11 bacterial strains were isolated in batch-culture and in continuous culture utilizing diphenylmethane, a non chlorinated structural analogon of DDM, as sole source of carbon and energy. One of these isolates, Alcaliaenes sp. cometabolizes DDM during the aerobic growth with diphenylmethane. By coimmobilization of Alcaligenes sp. and Enterobacter cloacae in Ca-alginate a system could be established, in which the reductive dechlorination of DDT and the oxidative degradation of DDM and diphenylmethane proceeds simultaneously in one reactor vessel.     

城市污泥土地利用研究

通过培养试验、盆栽试验和田间试验系统地研究了污泥的组分特征、性质及其农地和城市园林绿化地利用对作物或绿化灌木、土壤肥力及其环境的影响,结果表明,污泥富含有机质和氮磷养分,且养分当季有效性介于化肥农家肥之间。施用污泥将明显提高土壤肥力,表现改善土壤物理性质;增加土壤肥机质和氮磷水平,并增加土壤生物活性,因此施用污泥的处理作物产量较高,并有利于后茬作物的稳健生长。但污泥施用也存在重金属、病原物等污染     

Critical review of the influences of nanoparticles on biological wastewater treatment and sludge digestion

Nanoparticles (NPs), with at least one dimension less than 100?nm, are substantially employed in consumer and industrial products due to their specific physical and chemical properties. The wide uses of engineered NPs inevitably cause their release into the environment, especially wastewater treatment plants. Therefore, it is essential to systematically assess their potential impact on biological wastewater treatment and subsequent sewage sludge digestion. This review aims to provide such support. First, this paper reviews the recent advances on the analytical developments and nano–bio interface of NPs in wastewater and sewage sludge treatment. The effects of NPs on biological wastewater treatment and sewage sludge digestion and related mechanisms are discussed in detail. Finally, the key questions that need to be answered in the future are pointed out, which include on-line revelation of the changes of NPs in sewage and sludge environments, in situ assessment of the variations of microorganisms involved in these biological systems after they are exposed to NPs. Differentiation of the contribution of individual toxicity mechanisms to these systems, and the identification of under what conditions the nanoparticle-induced toxicity will be increased or decreased are also considered.     

Fate of Cryptosporidium oocysts, Giardia cysts, and microbial indicators during wastewater treatment and anaerobic sludge digestion.

The extent of reduction in selected microorganisms was tested during both aerobic wastewater treatment and anaerobic digestion of sludge at the wastewater treatment plant in Ottawa to compare the removal of two encysted pathogenic protozoa with that of microbial indicators. Samples collected included the raw wastewater, the primary effluent, the treated wastewater, the mixed sludge, the decanted liquor, and the cake. All of the raw sewage samples were positive for Cryptosporidium oocysts and Giardia cysts, as well as for the other microorganisms tested. During aerobic wastewater treatment (excluding the anaerobic sludge digestion), Cryptosporidium and Giardia were reduced by 2.96 log10 and 1.40 log10, respectively. Clostridium perfringens spores, Clostridium perfringens total counts, somatic coliphages, and heterotrophic bacteria were reduced by approximately 0.89 log10, 0.96 log10, 1.58 log10, and 2.02 log10, respectively. All of the other microorganisms were reduced by at least 3.53 log10. Sludge samples from the plant were found to contain variable densities of microorganisms. Variability in microbial concentrations was sometimes great between samples, stressing the importance of collecting a large number of samples over a long period of time. In all cases, the bacterial concentrations in the cake (dewatered biosolids) samples were high even if reductions in numbers were observed with some bacteria. During anaerobic sludge digestion, no statistically significant reduction was observed for Clostridium perfringens, Enterococcus sp., Cryptosporidium oocysts, and Giardia cysts. A 1-2 log10 reduction was observed with fecal coliforms and heterotrophic bacteria. However, the method utilized to detect the protozoan parasites does not differentiate between viable and nonviable organisms. On the other hand, total coliforms and somatic coliphages were reduced by 0.35 log10 and 0.09 log10, respectively. These results demonstrate the relative persistence of the protozoa in sewage sludge during wastewater treatment.     

Anaerobic storage as a pretreatment for enhanced biodegradability of dewatered sewage sludge

Dewatered sewage sludge is often stored still before further processing and final disposal. This study showed that anaerobic storage of dewatered sewage sludge could hydrolyze organic matter from the sludge matrix, and increase soluble organic acid content from 90 to 2400 mg/L and soluble organic carbon content from 220 to 1650 mg/L. Correspondingly, the contents of proteins, celluloses and hemicelluloses were reduced by 2-9%. Applying anaerobic storage markedly enhanced the efficiency of the subsequent bio-drying process on stored sludge. Correspondingly, biogas and odor gas were produced immediately after commencing the sludge storage. Anaerobic storage with odor control can be applied as a pretreatment process for dewatered sewage sludge in wastewater treatment plants.     

Performance of a commercial inoculum for the aerobic biodegradation of a high fat content dairy wastewater

The effectiveness of a commercial inoculum for degrading a dairy wastewater with high fat content was evaluated, and compared with an activated sludge inoculum from a dairy wastewater treatment pond. Both inocula reached similar chemical oxygen demand removal in batch experiments. The population dynamics was also studied by determining heterotrophic counts. Predominant microorganisms were differentiated by colony morphology and genomic fingerprinting (BOX-PCR) analysis. The higher population diversity and the wider range of CO2 production rate observed in batch reactors inoculated with activated-sludge, indicated that microorganisms from this inoculum were well adapted and may have had synergic activity for the degradation of the dairy effluent. When the bioreactor was operated with the commercial inoculum in continuous mode, according to its microbial growth kinetics, other microorganisms became predominant. These results showed that inoculated microorganisms did not persist in the open system and periodic addition of microorganisms may be needed to achieve a high performance treatment.     

Biological Degradation of Crude Oil Refinery Sludge with Commercial Surfactant and Sewage Sludge by Co-Composting

This study determined the potential of surfactant and sewage sludge in enhancing degradation of oil sludge. A mixture of oil sludge, surfactant, and sewage sludge was co-composted for 24 weeks in the laboratory. Physical and chemical parameters in the compost were measured every four weeks. Isolated microorganisms were characterized by molecular techniques. The pH in all experiments remained between 8 and 6.4. CO₂ evolution reached 5503 µg/dwt/day by the twenty-fourth week. The dominant bacterial species were Acinectobacter, Rodococcus, mycobacterium, Pseudomonas, Bacillus, Arthrobacter, and Staphylococcus species and fungi were Pleurotus, Penicillium, and Aspergillus sp. TPH was reduced by 92% in the sewage sludge and surfactant treatment, 75 and 81% in other treatments, and 44.2% in the control. PAH concentrations were reduced by between 75 and 100%. The results indicate that a careful application of surfactant and sewage sludge could enhance oil sludge degradation in a compost system.     

Metagenomic analyses reveal phylogenetic diversity of carboxypeptidase gene sequences in activated sludge of a wastewater treatment plant in Shanghai,China

Activated sludge of wastewater treatment plants carries a diverse microflora. However, up to 80–90 % of microorganisms in activated sludge cannot be cultured by current laboratory techniques, leaving an enzyme reservoir largely unexplored. In this study, we investigated carboxypeptidase diversity in activated sludge of a wastewater treatment plant in Shanghai, China, by a culture-independent metagenomic approach. Three sets of consensus degenerate hybrid oligonucleotide primers (CODEHOPs) targeting conserved domains of public carboxypeptidases have been designed to amplify carboxypeptidase gene sequences in the metagenomic DNA of activated sludge by PCR. The desired amplicons were evaluated by carboxypeptidase sequence clone libraries and phylogenetic analyses. We uncovered a significant diversity of carboxypeptidases present in the activated sludge. Deduced carboxypeptidase amino acid sequences (127–208 amino acids) were classified into three distinct clusters, α, β, and γ. Sequences belonging to clusters α and β shared 58–97 % identity to known carboxypeptidase sequences from diverse species, whereas sequences in the cluster γ were remarkably less related to public carboxypeptidase homologous in the GenBank database, strongly suggesting that novel carboxypeptidase families or microbial niches exist in the activated sludge. We also observed numerous carboxypeptidase sequences that were much closer to those from representative strains present in industrial and sewage treatment and bioremediation. Thermostable and halotolerant carboxypeptidase sequences were also detected in clusters α and β. Coexistence of various carboxypeptidases is evidence of a diverse microflora in the activated sludge, a feature suggesting a valuable gene resource to be further explored for biotechnology application.     

Magnetization of activated sludge by an external magnetic field

Magnetization of acclimated activated sludge with the application of an external magnetic field was observed using a magnetic force microscope and can be expressed as the visual magnetic flux density graph. FeCl₃ addition up to 0.1% (w/v) into the sludge, which was acclimated with synthetic sewage wastewater, enhanced the magnetization. Such magnetization was also observed in the activated sludge obtained from the practical wastewater treatment plants of a food processing plant and sewage wastewater. FeCl₃ addition also enhanced the sludge magnetization. The possibility is suggested that this magnetization causes the flock to enlarge and enhance sedimentation of the activated sludge on application of an external magnetic field.     

污水处理过程中微生物群落多样性及其对环境因子响应的研究进展

污水生物处理系统的性能和稳定性与微生物群落结构和动态密切相关。通过深入了解活性污泥中微生物群落结构及其影响因素,有助于提高污水厂污染物的去除效果。在不同污水活性污泥处理系统中细菌群落主要以变形菌、绿弯菌、放线菌、厚壁菌和拟杆菌为功能菌群;活性污泥中寄居的大多数真菌来自于子囊菌门,还有少量担子菌门;古菌以产甲烷菌为主;而病毒中分布最广的噬菌体和致病性病毒是最主要的关注点。本文通过对相关文献分析及总结,综述了进水组成、不同处理工艺、参数(理化参数和运行参数)、地理位置和气候条件等环境因子对活性污泥中细菌、真菌、古菌以及病毒群落组成的影响,尽可能全面地介绍污水厂微生物群落多样性及其对环境因子的响应。同时,对未来研究方向进行探讨,以期能够为活性污泥中功能微生物的应用及调控提供理论和应用基础。