一株PVA降解菌的筛选及其降解条件的优化

从被PVA直接污染的环境中筛选获得一株能高效降解聚乙烯醇的微生物菌株Z5。对其生长过程及PVA降解过程进行研究,发现该菌株在48 h内可降解79.24%的聚乙烯醇(PVA)。同时研究了Z5菌株的降解特性,结果表明,该菌株降解PVA最适条件为:温度30℃、pH6.2、装液量30 mL;牛肉膏、蛋白胨、NaCl、PVA浓度分别为:0.05 g/L、0.1 g/L、2 g/L和2 g/L。     

盐单胞菌H17降解苯酚的响应面法优化及动力学

为获得盐单胞菌(Halomonas sp.)H17降解苯酚的最优条件,在单因素试验的基础上,通过Box-Behnken设计试验与响应面法,考察温度、pH、葡萄糖浓度对H17降解苯酚的影响,并通过动力学模型探究该菌株的生长和苯酚降解特性。结果表明,H17降解苯酚的最优条件为30℃、pH=8.0、葡萄糖质量浓度0.8g/L,在此条件下,苯酚降解率预测值为74.39%,实际值为73.92%,表明该模型可靠。该菌株降解苯酚动力学模型符合Haldane模型,其最大比降解速率、饱和常数和抑制常数分别为0.35h~(-1)、165.91mg/L和460.13mg/L。响应面法优化得到的生物降解条件准确,可为高盐含酚废水处理提供依据。     

一株对硝基苯酚降解菌的筛选鉴定及其降解特性

从受甲基对硫磷污染的土壤中分离筛选得到一株能够以对硝基苯酚(PNP)作为唯一碳源、氮源生长的菌株,命名为TM.经16S rDNA序列分析初步鉴定该菌株为节杆菌(Arthrobacter).考察了该菌株在PNP浓度、盐度(NaCl)、pH、外加碳源(葡萄糖)、外加氮源等因素下对PNP降解特性的影响.结果表明:该菌株对PNP的最大耐受质量浓度为300 mg/L,并在降解的过程中生成NO2-该菌株的耐盐能力可达0.30％(质量分数),其最佳pH为8.在此pH下,200 mg/L的PNP在16h时即可被完全降解,添加0.30％(质量分数)的葡萄糖可使生物量和降解速率达到最大,牛肉膏作为外加氮源最有利于该菌株对PNP的降解.     

好氧反硝化苯酚降解菌的分离鉴定及动力学

从驯化菌群中分离筛选出一株好氧反硝化苯酚降解细菌,经生理生化反应及16S rDNA测序,鉴定为Diaphorobacter属细菌。在好氧条件下,该菌株以苯酚为唯一碳源和能源,利用NO-3-N作为反硝化电子受体,其生长与反硝化特性研究表明:在接种量5%(体积分数),30℃,180 r/min振荡培养条件下,菌株降酚能力可达1 400 mg/L,同时,能有效去除初始浓度为165 mg/L的硝酸盐氮,60 h其去除率为91.5%,高含量苯酚对菌体生长有一定的抑制作用。应用Haldane方程对其生长过程进行动力学模拟,拟合曲线与实验测定值相关性良好,各参数分别为μmax(最大比增长率)0.324 h-1,Ks(半饱和常数)9.36 mg/L,Ki(抑制常数)146.72 mg/L,通过理论分析及实验验证得,该菌株苯酚降解动力学与其生长动力学表现出相似的趋势。     

TiO2薄膜光催化降解双酚A的研究

采用sol-gel法制备TiO2薄膜.以该薄膜为催化剂,研究了在H2O2存在的条件下,对内分泌干扰物质双酚A的光催化降解反应.分别讨论了pH值、H2O2的加入量、双酚A的初始浓度以及光照时间对降解反应的影响.结果表明,在pH=4,30 mg/L的H2O2中对初始浓度为50 mg/L的双酚A溶液光照180 min有较好的降解效果.     

酸性媒介黄GG生物降解性能的试验研究

通过试验研究酸性媒介黄GG染料在厌氧、好氧条件下的生物降解机理、降解能力及共代谢降解效果.试验结果表明,厌氧菌能够通过葡萄糖共代谢作用很快降解酸性媒介黄GG;而好氧条件下经驯化活性污泥不能降解酸性媒介黄GG,经过较长时间驯化活性污泥能降解酸性媒介黄GG,但降解效果很差.葡萄糖浓度的升高对提高酸性媒介黄GG厌氧生物降解率有利,当葡萄糖浓度为2000 mg/L时,40mg/L酸性媒介黄GG的12和60 h厌氧生物降解率分别达到81.5%和93.5%.酸性媒介黄GG浓度对厌氧菌的生物降解能力也有影响.当葡萄糖浓度为2000 mg/L,酸性媒介黄GG(浓度为20～100 mg/L)的厌氧降解率最好,降解效率达到了94%,说明厌氧菌对酸性媒介黄GG的降解能力较好.     

畜禽养殖污水中高效氨氮降解菌的筛选、鉴定及生长条件研究

从养殖污水中分离纯化得到1株高效氨氮降解菌,对其进行形态特征、生理生化、16S rDNA序列分析以及最佳生长条件研究,并将菌株投入养殖污水降解污水中的氨氮。结果表明：AN4菌株在NH4＋-N初始质量浓度为50 mg/L的条件下,24 h内的氨氮降解率为92.5%;初步鉴定该菌株为苍白杆菌属（Ochrobactrum sp.）,菌株的16S rDNA序列在Gen-Bank的登录号为GU345782;AN4菌株在装液量为60.64 mL,pH为7.06,葡萄糖为6.0 g/L的条件下培养,菌株的降解率可以达到94.28%;菌株对养殖污水中氨氮的降解率为12.3%。苍白杆菌菌属能够降畜禽养殖污水中的氨氮还未见报道,AN4菌株的筛选获得为生物降解养殖污水中的氨氮又提供了一种新型菌株。     

四溴双酚A对土壤酶活性的影响

采用室内模拟试验方法,研究了四溴双酚A对土壤多酚氧化酶、过氧化氢酶和脱氢酶活性的影响.结果表明,四溴双酚A对土壤多酚氧化酶和过氧化氢酶有一定的激活效应,这可能是土壤微生物在受到外源四溴双酚A胁迫时产生了应激反应,通过增加多酚氧化酶和过氧化氢酶的产生量来降低四溴双酚A及其代谢、中间产物对其产生的危害;同时,四溴双酚A对土壤脱氢酶产生一定的抑制效应,表明其对土壤微生物活性具有一定的抑制作用,但在试验设置的四溴双酚A浓度范围内基本未达到显著水平(P>0.05).     

Fe/AC非均相Fenton体系降解BPA

采用常规浸渍法制备和超声浸渍法制备活性炭载铁催化剂,作为非均相Fenton反应的催化剂。采用电镜扫描和能谱分析对催化剂的形貌特性进行分析,以双酚A为目标降解物,考察催化剂的降解性能。结果表明,超声浸渍法制备的催化剂,活性组分含量高,在载体表面负载均匀,催化剂性能稳定。催化剂用量为2 g/L,H2O2浓度为0.06 mol/L,p H值为6的条件下,催化降解BPA的效率达90%。     

涤纶碱减量废水中对苯二甲酸的好氧生物降解性能研究

采用城市污水处理厂的活性污泥做菌源,在实验室条件下研究了对苯二甲酸(TA)和乙二醇(EG)的好氧生物降解性能,着重考察了EG对TA好氧生物降解性能的影响.试验结果表明,微生物以TA、EG作为惟一的碳源需要一定的驯化时间,EG作为惟一碳源的驯化时间比TA的驯化时间长.但微生物一旦被驯化,EG比TA具有较快的降解速度,当TA为1100mg/L时,其平均降解速率为27.5 mg COD/g MLSS·h,而EG为1200mg/L时,其平均降解速率达到36.7 mg COD/g MLSS·h.在相同污泥负荷条件下,TA降解的滞后期受TA浓度影响不大,TA的好氧降解不存在明显的抑制浓度.EG不会抑制TA的初级生物降解,但会抑制TA的最终生物降解.     

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.     

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.     

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...     

污泥堆肥施用于草坪草栽培:Zn和Cu的分布特征简

为了探索污泥堆肥中重金属在土壤-植物系统中的积累与转移特性，通过温室盆栽实验，分析了污泥堆肥对草坪草高羊茅、黑麦草和白三叶生物量积累的情况，研究了污泥堆肥中Zn和Cu在植物和土壤中的分布特征。结果表明，污泥堆肥施用可以有效促进3种草坪草的积累生物量，在0~6 kg/m²的污泥堆肥施用量范围内，草坪草的生物量积累随着施用量的增加而提高。土壤中Zn和Cu的含量随污泥堆肥施加量的增加而增大，85%以上的Zn和Cu残留在土壤中。污泥堆肥中的Zn和Cu均可以被植物吸收，随着污泥堆肥施用量的增加，草坪草对Zn和Cu的吸收量增大，但当污泥堆肥施用量超过一定阈值时，草坪草吸收Zn和Cu不再增加，甚至减少；对于不同的草坪草，这一阈值有所不同。植物对Zn和Cu的吸收量只占土壤中Zn和Cu减少量的5%左右。根据生物富集系数（BCF）的计算结果推测，污泥堆肥的施用对土壤环境的影响大于对植物体内累积Zn和Cu的影响。     

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。     

不同水温下鲴鱼对铜绿微囊藻的控制作用及对水质的影响

在室内受控模拟条件下开展实验,研究了在19、23、27、31、35℃5个水温梯度下鲴鱼对铜绿微囊藻和水质的影响。研究结果表明,在不同水温下,鲴鱼对铜绿微囊藻具有较强的控制作用,实验结束时铜绿微囊藻密度减少至初始密度的18%~30%,摄食率和消化率分别为6.83×104~8.32×104cells/(g·d)、93%~98%;叶绿素a的去除率为68%~88%;实验组TP、TN去除率分别为22%~25%、20%~38%,对照组的分别为80%~94%、28%~40%。对照组NH+4-N浓度变化很小(0.071~0.073 mg/L),而实验组氨氮浓度显著增大(2.222~3.645 mg/L),分别为初始值的31、34、42、51和46倍。     

Marine macroalgal community structure, metal content and reproductive function near an acid mine drainage outflow

Marine macroalgal communities were examined near the outflow of acid mine drainage (AMD) from the Britannia Mine, British Columbia, Canada. No marine algae were present within 100 m of the mouth of Britannia Creek, which carries the AMD into the marine environment. At greater distances (300-700 m) from this Creek, mean summer cover of filamentous green algae, mostly Enteromorpha intestinalis, was >60%, which was significantly higher than at nearby reference stations. At still greater distances (600-1000 m) from Britannia Creek, Fucus gardneri dominated algal communities that were similar to those at reference stations. No consistent differences were detected in mean plant length, mean per cent cover or mean oocyte production between F. gardneri near Britannia Creek and those at reference stations. Cu body burden in F. gardneri near Britannia Creek was five to 17 times higher than in reference plants.     

全氟辛烷磺酸盐(PFOS)在藻渣/小球藻上的吸附行为及机理

为了开发新型廉价生物吸附剂,以高效吸附去除水体中全氟辛烷磺酸盐(PFOS),对小球藻提取生物柴油后的藻渣吸附酸性水体中的PFOS进行了吸附行为及机理的研究。小球藻提取生物质柴油后,比表面积、孔容、孔径几乎没有变化;等电点由3.3降低至2.7;蛋白质含量由51.45%提高到57.35%。在酸性条件下(pH≤3),小球藻和藻渣对PFOS的吸附率均达到99%以上;随着pH值增加至7,二者的吸附去除率迅速降低,但仍保持在22%~26%。小球藻和藻渣对PFOS的最大吸附容量分别为353.69 mg/g和444.83 mg/g。Freundlich模型能较好地拟合二者对PFOS的吸附数据,表明为多层吸附,即小球藻以静电吸引的形式吸附PFOS阴离子,并疏水分配至所含蛋白质中;而藻渣中含量较高的蛋白质对PFOS的疏水性分配作用是导致藻渣吸附量增高的主要原因。