氮源对克雷伯氏菌NⅢ2分泌絮凝剂特性的影响

实验研究了蔗糖为碳源,硝酸钠、脲、蛋白胨、硫酸铵和氯化铵等氮源对NⅢ2发酵产絮凝剂的影响。结果表明,发酵液起始pH值为7.50,以硝酸钠为氮源,发酵液pH会上升,升至7.60～8.34时,NⅢ2菌株开始大量分泌微生物絮凝剂,发酵72 h,产量可达7.5 g/L,该产量是目前报道的克雷伯氏菌产絮凝剂的最高值。脲为氮源,pH则下降,降至5.04～6.49时,大量分泌絮凝剂,发酵72 h产量达5.2 g/L。蛋白胨、氯化铵和硫酸铵等为氮源时,pH下降十分明显,pH小于3.71时有絮凝剂分泌,发酵72 h产量约2.0 g/L或更小。以硝酸钠和脲为氮源时,发酵液中有黄色物质分泌,该黄色物质出现或黄色逐渐加深,是NⅢ2菌高产絮凝剂的标志。除硫酸铵外,其他氮源发酵所产絮凝剂为O-糖蛋白。当以硝酸钠、脲、蛋白胨、硫酸铵和氯化铵为氮源时,絮凝剂中蛋白的含量分别为9.55%、33.28%、19.39%、13.81%和15.51%,且蛋白含量越高,絮凝剂活性越大。     

Mg2+对克雷伯氏菌NIII2及其诱变菌产絮凝剂特性的影响

研究了Mg2+对克雷伯氏菌NIII2及其诱变株NIII2-1、NIII2-2发酵产絮凝剂特性的影响作用。实验表明,发酵液未外加或投加较少量Mg2+时,3菌株均不分泌黄色物质,且易产酸,致使絮凝剂产量低,小于1.5 g/L。发酵液中加入Mg2+的浓度在0.5~0.7 mmol/L范围,絮凝剂产生时,伴随黄色分泌物出现,发酵液p H稳定在7.5左右,同时絮凝剂产量大大提高,可达9.7 g/L。未投加Mg2+,3菌株所产絮凝剂Zeta电位负值较大,分别为-59.2、-56.6、-52.1 m V,且蛋白质与糖含量比值小于0.5,絮凝活性低;而投加Mg2+所产絮凝剂Zeta电位值可升至-48.0 m V,3菌株所产絮凝剂中蛋白和糖含量比值分别可提高到1.87、3.29、2.03,对高岭土所产生的SS去除率均大于93%。未投加Mg2+时,诱变株NIII2-1、NIII2-2所产絮凝剂含有相当多的O-链接和N-链接的结构,而其他情况下所产絮凝剂则主要是O-链接结构。     

微生物絮凝剂产生菌的筛选及其培养条件优化的研究

采用常规的细菌分离纯化方法从土壤中分离出絮凝剂产生菌菌株,经过驯化培养后,以发酵液对高岭土混悬液的絮凝效果为指标,筛选出2株高效絮凝剂产生菌.采用单因素试验方法和正交试验设计方法,分析了影响絮凝效果的主要因素,对2个菌株的最佳培养条件进行了优化研究.结果表明:菌株S3产絮凝剂的最佳培养条件是碳源为葡萄糖(20g/L),氮源为酵母膏(2.5 g/L),培养温度为28℃,初始pH值为8,通气量为50 r/min;菌株S21产絮凝剂的最佳培养条件是乙醇(15 g/L),氮源为复合氮源(酵母膏 脲 硫酸铵)(1.6 g/L),培养温度为28℃,初始pH值为9,通气量为200r/min.     

培养基对菌产微生物絮凝剂的影响研究

研究了培养基成分种类及其用量对菌产微生物絮凝剂的影响。结果表明,较高的C/N比对菌产絮凝剂有利,碳源中的蔗糖是菌株Aeromonassp.N11产絮凝剂的良好碳源,氮源以采用复合氮源为佳。培养基中加入酵母膏有利于絮凝剂的产生。NaCl能够促进所产絮凝剂的絮凝活性,碳源蔗糖和氮源脲对菌产絮凝剂的影响最大。利用正交实验得出产絮凝剂培养基的最佳配比为蔗糖20g/L,酵母膏08g/L,脲05g/L,硫酸胺05g/L,NaCl7g/L。     

微生物絮凝剂的制备及其对城市污水厂污泥的脱水

研究利用甘蔗渣作为廉价原材料制备微生物絮凝剂并探讨其对城市污泥的脱水性能。按0.5%最佳接种量接种,并利用发酵罐进行批式发酵培养,培养60 h后的发酵液具有最佳絮凝效果,投加量为5.0 mg/L时较优,污泥脱水率从75.60%提高到84.2%,污泥含水率从95.82%降至76.21%。此时絮凝剂粗产量为1.16 g/L。培养108 h后,发酵液仍具有显著的絮凝效果,能使污泥含水率维持在76.81%左右。补料发酵实验表明,恒pH培养会抑制微生物分泌絮凝剂,最佳絮凝效果为72 h的发酵液,投加量5.0 mg/L,污泥含水率降至76.47%。通过补料以及不控制pH后,发酵液絮凝效果迅速上升,投加不同量的发酵液使污泥的含水率保持在76.22%~75.60%之间。综合来说,补料在能减少原料浪费的同时也可以有效地提高絮凝剂的絮凝效果。     

含硫无机物对克雷伯氏菌NIII2产絮凝剂特性的影响

研究了含硫无机物对克雷伯氏菌NIII2发酵产絮凝剂特性的影响作用。结果表明:未外加硫或投加足量硫化钠时,NIII2菌,因易产酸,絮凝剂产量低,约2.14 g·L~(-1);而投加足够(16 mg·L~(-1),以硫元素计)硫代硫酸钠和硫酸钠时,絮凝剂产量提高,最高可达9.03 g·L~(-1)。与未外加硫相比,外加足够硫酸钠或硫代硫酸钠,能使絮凝剂中蛋白质相对含量分别提高29.8%和25%,并提高絮凝剂中总巯基、二硫键含量以及Zeta电位,致使絮凝剂粒径可广泛分布于0.5~3.3μm范围内,且大粒径分子所占比例提高,聚合度增大,从而稳定絮凝剂活性和性能。投加8.0 mg·L~(-1)絮凝剂,2 g·L~(-1)高岭土所产生的SS去除率达93%左右。NIII2菌所产絮凝剂为糖蛋白类,未投加含硫无机物或投加硫化钠时所产絮凝剂为O-糖苷键相连的糖蛋白,而投加硫代硫酸钠、硫酸钠时所产絮凝剂则为絮凝剂为非O-糖苷键糖蛋白。     

絮凝剂产生菌B-7的培养条件优化及生长动力学研究

从成都市土壤中筛选分离了1株具有稳定高效的微生物絮凝剂产生菌B-7。考察了碳源、氮源、温度、培养时间、pH等多种因素对絮凝剂（MBF-7）絮凝效果的影响。实验结果表明,该菌株产絮凝剂的最佳培养条件为：碳源为淀粉,氮源为硫酸铵,培养时间为72 h,初始pH为7.0,温度为30℃,对0.4%高岭土悬浊液的絮凝率达到91.3...     

培养基对菌产微生物絮凝剂的影响研究

研究了培养基成分种类及其用量对菌产微生物絮凝剂的影响。结果表明，较高的C／N比对菌产絮凝剂有利，碳源中的蔗糖是菌株Aeromonns sp．N11产絮凝剂的良好碳源，氮源以采用复合氮源为佳。培养基中加入酵母膏有利于絮凝剂的产生。NaCl能够促进所产絮凝剂的絮凝活性，碳源蔗糖和氮源脲对菌产絮凝剂的影响最大。利用正交实验得出产絮凝剂培养基的最佳配比为：蔗糖20g／L，酵母膏0．8g／L，脲0．5g／L，硫酸胺0．5g／L，NaCl7g／L。     

生物絮凝剂产生菌群发酵特性及动力学

从土壤中分离、筛选得到2株具有协同发酵的微生物絮凝剂产生菌。通过单因素实验考察了碳源、氮源、不同C/N等多种发酵条件对复合菌株产絮的影响,并对复合菌株的生长动力学进行了研究。当碳源为蔗糖、氮源为草酸铵、C/N为30∶1,pH=7.0、在30℃,160 r/min的摇床速度下培养24 h,其发酵液对4 g/L的高岭土的悬浊液的絮凝率达到99.3%。根据Logistic方程,得到复合型生物絮凝剂产生菌群的生长动力学模型与实验数据能较好地拟合,基本反映了复合菌群生长的动力学特征。     

简单芽孢杆菌产高效微生物絮凝剂

通过从绿化植物根际土壤和污水处理厂的活性污泥中分离筛选絮凝剂产生菌,得到一株稳定高效的微生物絮凝剂产生菌PS1,根据形态学特征、生理生化实验以及16S rDNA序列分析将其鉴定为简单芽孢杆菌(Bacillus simplex)。对菌株PS1产生絮凝剂的最佳培养时间、絮凝活性分布以及pH、CaCl2、絮凝剂投量对絮凝效果的影响进行了研究,并考察了其对实际废水的絮凝效果。结果表明,菌株PS1产絮凝剂的最佳培养时间为36 h,产生的絮凝活性物质全部存在于发酵液离心后的上清液中;当pH为7.0～8.5、CaC12投量为0.25～0.35 g/L、发酵液投加量的体积分数为1.5%～2.5%时,菌株PS1发酵液对4 g/L的高岭土悬浊液的絮凝效果最佳,絮凝率达到97%。菌株PS1所产絮凝剂对城市污水、啤酒废水、淀粉废水、医院废水的絮凝率可达90%以上。     

Effects of Mn(II) and Fe(II) on microbial removal of arsenic (III)

Goal, scope, and background  Arsenic contamination in groundwater creates severe health problems in the world. There are many physiochemical and biological methods available for remediation of arsenic from groundwater. Among them, microbial remediation could be taken as one of the least expensive methods, though it takes longer treatment time. The main objective of this research was to study the improvement on remediation by addition of some essential ion salts such as Mn and Fe. Materials and methods   Staphylococcus aureus, Bacillus subtilis, Klebsiella oxytoca, and Escherichia coli were taken as model microbes from Dhulikhel, 30 km east from Kathmandu, Nepal. Results and discussion  Microbes used in this study showed different abilities in their removal of As(III) with and without addition of Mn and Fe salts. The trend of remediation increased with time. S. aureus was found to be the best among the microbes used. It showed almost 100% removal after 48-h culture, both with and without Fe and Mn salts. Rate of removal of As increased with addition of Fe and Mn for all microbes. Removal efficiency was found to increase by about 32% on average after addition of salts in 24-h cultures of S. aureus.     

Bioindicators for toxicity assesment of effluents from a wastewater treatment plant

The discharge of effluents and toxic compounds into aquatic systems represents a growing environmental problem involving an impact on water ecology and potential effect on human health. Most municipal wastewaters are complex mixtures; their complexity led as to carry out a hazard assessment using chemical analyses and biological tests.This study investigates biochemical alteratiobns in two sentinel organisms, the Anodonta cygnea mussel and the Xenopus laevis frog exposed for different lengths of time to various concentrartion of wastewater of the S. Antonino Ticino treatment plant. The results point out the long-life of toxic compounds.     

Patterns of volatile metabolites and nonvolatile trichothecenes produced by isolates of <Emphasis Type="Italic">Stachybotrys,Fusarium, Trichoderma,Trichothecium</Emphasis> and <Emphasis Type="Italic">Memnoniella</Emphasis>

We reported previously that trichodiene, a volatile trichothecene derivative, was produced by a Stachybotrys isolate, also known to produce highly cytotoxic, non-volatile, macrocyclic trichothecenes (satrotoxins). We investigated the relationship between the production of trichodiene and various non-volatile trichothecenes for several molds. Volatile metabolites were concentrated by adsorption on Tenax TA and analyzed by GC/MS, while non-volatile metabolites were separated by HPLC, derivatized and analyzed by GC/MS. Stachybotrys chartarum isolates producing macrocyclic trichothecenes secreted significantly larger amounts of trichodiene and other sesquiterpenes than isolates which only produced simple trichothecenes. The amounts of secreted trichodiene were relatively small in all cases. With the exception of Memnoniella, which excreted small amounts of sesquiterpenes, the other isolates produced varying amounts of sesquiterpenes, including trichodiene, as well as simple tricothecenes, no detectable trichodiene, but large amounts of griseofulvin derivatives. In Stachybotrys there is apparently a correlation between trichodiene and macrocyclic trichothecene production. In the remaining isolates, there was no simple relationship between trichodiene and non-volatile trichothecene synthesis. Trichodiene is produced in larger amounts by Stachybotrys isolates, which also produce satratoxins, but it will be difficult to utilize this metabolite to detect toxic isolates in buildings due to the relatively small amounts excreted.     

氧化亚铁硫杆菌浸铜作用研究

为研究氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.f)对铜浸出的作用,从某煤堆积水中分离得到A.f菌,利用该菌对铜进行浸出实验,设置3个处理,3个处理的浸出液分别为9 K培养基(简称S),成熟菌液(简称MS)和过滤除菌液(简称FS)。结果表明,3个处理中铜都得到了浸出,浸出铜浓度按S、FS和MS依次递增分别为4 433、5 377和6 296 mg/L;浸出初期,MS中的铜,浸出速度最快,过滤除菌液中次之,而培养基中的速度比较稳定,比前两者均慢,24 h后三者浸铜速度趋近一致;三者中pH、Eh变化相似,pH均先升高至3.4左右保持相对稳定,Eh均先迅速下降至280 mV后保持稳定。由实验可知,氧化亚铁硫杆菌主要在浸出初期促进了铜的浸出,且菌液中溶解氧氧化Fe2+以及酸性条件下氧化Cu0对铜的浸出作用不容忽视。     

利用发光菌和大型蚤对北方某城市再生水急性毒性的调查

利用发光菌和大型蚤作为受试生物测定了北方某城市5个再生水原水(城市污水厂二级出水)和2个再生水处理系统的各工艺出水的急性毒性.结果表明,各再生水原水对大型蚤和发光菌具有不同程度的毒性效应,其中工业废水占较大比例的K和B厂再生水原水的大型蚤48 h总抑制率分别高达90%和100%,发光菌发光抑制率分别达到74.2%和46...     

不同质量浓度黄菖蒲和狭叶香蒲对铜绿微囊藻的化感作用简

分别采用黄菖蒲（Iris pseudacorus L.）、狭叶香蒲（Typha angustifolia L.）和铜绿微囊藻（Microcystis aeruginosa）共生培养的实验方法研究了不同质量浓度黄菖蒲、狭叶香蒲对铜绿微囊藻的化感作用。结果表明，黄菖蒲在质量浓度大于10 g/L时对初始密度为1.0×10⁷ ind/mL的铜绿微囊藻具有较好的抑制作用，表现为黄菖蒲质量浓度为10、20和40 g/L时，第15天对铜绿微囊藻的抑制率分别为30.1%、51.8%和84.0%；狭叶香蒲在质量浓度大于20 g/L时对铜绿微囊藻有明显的抑制作用，表现为狭叶香蒲质量浓度为20 g/L和40 g/L时，第15天对铜绿微囊藻的抑制率分别为34.2%和77.7%，实验过程中，铜绿微囊藻叶绿素a含量逐渐减少，而藻密度、SOD活性及MDA含量先增加后逐渐降低，表明经过一段时间持续地化感胁迫，黄菖蒲和狭叶香蒲可以诱导铜绿微囊藻产生氧化胁迫，导致细胞结构严重损伤和叶绿素大量分解，从而强烈抑制铜绿微囊藻的生长。     

Inductive potency of TCDD, TBDD and three 2,3,7,8-mixed-halogenated dioxins in liver microsomes of male rats. Enzyme kinetic considerations

The enzyme inducing potency of single doses of three 2,3,7,8-substituted mixed halogenated dibenzo-p-dioxins was investigated and compared with 2,3,7,8-TCDD and 2,3,7,8-TBDD. All substances showed a quite similar potency for EROD induction. The use of a substrate concentration of 0.5 μM ethoxyresorufin is strongly recommended.     

隐孢子虫3种检测方法比较

为建立一套行之有效的隐孢子虫灭活效果评价方法，在构建鸡源隐孢子虫C. baileyi动物模型的基础上，选用3种检测方法（抗酸染色、饱和蔗糖悬浮镜检和荧光检测），对鸡源隐孢子虫进行镜检、数量统计，并比较3种方法的优劣及适用范围。结果显示：荧光染色法具有最佳的检测效率（检出数量为改良抗酸染色法，饱和蔗糖悬浮镜检法的2.1和2.6倍；检测时间为120 min），并能够进行隐孢子虫的活性鉴定，可以作为饮用水消毒剂灭活隐孢子虫的评定方法，是一种高效、简便、较为廉价，并具有较大发展前景的检测方法。     

Physical-chemical and ecotoxicological evaluation of water based drilling fluids used in Italian off-shore

In order to evaluate the effects on the marine ecosystem caused by an eventual discharge into sea of water based drilling fluids, as current legislation allows, chemical and ecotoxicological analyses were performed on the most common drilling muds and products used in Italian off-shore activities. The chemical analysis on drilling fluids involved the leaching test and the measurement of total content of heavy metals, whereas biodegradation tests were performed on the products used in mud's formulations. As for ecotoxicological evaluation, two marine organisms, the crustacean Artemia salina and the diatom Phaeodactylum tricornutum, were selected to determine the LC₅₀ and the EC₅₀ respectively.     

耐寒人工湿地植物石龙芮和酸模联用研究

为了提高人工湿地在寒冷季节的运行效率，对2种非夏季植物作为湿地植物处理生活污水的可行性进行了研究。结果表明,在本实验条件下2种植物对N、P元素都具有很好的去除效果，对COD的去除也达到45%～50%。通过单一植物系统和复合植物系统的处理效果比较，发现石龙芮酸模复合植物系统对污水中的P元素和COD的去除率更高。研究表明，石龙芮和酸模作为人工湿地植物具有可行性，与常规植物互补使用能在一定程度上延长人工湿地的运行时间。