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。     

PVA降解菌的复配组合及其紫外诱变处理的研究

对已筛选出的4株PVA降解菌进行不同的组合后测定PVA降解率,发现Z5与Z8菌株混合后在1周内对PVA的去除率达到了所有组合中的最高值52.07%,比单菌株提高了约22%。采用紫外照射的方法对混合菌进行诱变并利用正交实验研究其特性,结果表明,诱变后的混合菌在1周内降解了91.46%的PVA,并且碳源浓度对酶活的影响最为显著。当pH为7,碳源、氮源含量分别为1.5 g/L、0.6 g/L,NaC l浓度为1.5 g/L时,诱变菌株处于最佳生长状态。     

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。     

润滑油高效降解菌的筛选及降解性能

实验以被石油污染的土壤为出发菌源,以润滑油为唯一碳源,经过筛选分离得到4株对润滑油具有降解能力的菌株。经过形态观察、生理生化实验初步鉴定发现,4株菌株分别为黄单胞菌属(Xanthomonas)、动胶菌属(Azotobac-ter)、假单胞菌属(Pseudomonas)和黄杆菌属(Flavobacterium),其中菌株G4为黄杆菌属,其润滑油降解效率最高。研究菌株G4降解性能的影响因素发现,实验中的各因素对润滑油降解率的影响大小依次为:温度>葡萄糖浓度>硫酸铵浓度>pH值。在温度20～40℃下,菌株G4对润滑油均具有一定的降解能力。在适宜的温度范围中,pH值5.0～9.0范围内,菌株G4的润滑油降解率随pH值的变化很小,且均在80%以上。菌株G4在以润滑油为唯一碳源时的最佳培养条件为:温度30℃,pH值为9.0,硫酸铵浓度为1.0 g/L。在此条件下培养36 h,100 mL的G4培养液对200μL润滑油的降解率可达84.6%。     

三乙胺降解菌SYA-1的分离、降解性能与动力学

从农药废水处理池的活性污泥中分离筛选得到1株高效三乙胺降解菌株SYA-1,根据菌株SYA-1的形态特征、生理生化特性和16S rRNA基因序列同源性分析,此菌株鉴定为Achromobacter sp.。菌株SYA-1能以三乙胺为惟一碳、氮源生长,并在24 h内完全降解200 mg/L的三乙胺。环境因素影响实验表明,在温度30℃,初始pH 7.0,NaCl浓度≤10 g/L条件下,菌株SYA-1生长良好且对三乙胺的降解效率最佳;金属离子对菌株生长和三乙胺降解的抑制程度表现为:Cu2+Co2+Ag+Cd2+Fe3+Pb2+。菌株SYA-1降解三乙胺的动力学过程可用Haldane模型模拟,其参数为μmax=0.123h-1;K s=82 mg/L;K i=215 mg/L。为含三乙胺废水的生物降解提供了理论依据和菌株资源。     

11株白腐真菌对5种偶氮染料脱色效果比较及其脱色条件优化

通过11株白腐真菌对5种偶氮染料脱色效果比较的基础上,从中筛选出一株对偶氮染料酸性铬蓝K脱色效果较好的菌株云芝SG0027,并对其脱色条件进行优化。在单因素和Plackett-Burman实验的基础上,采用Box-Behnken设计方法,以酸性铬蓝K脱色率为响应值,对其降解条件进行优化。结果表明,云芝对偶氮染料酸性铬蓝K的最佳降解条件为:温度29.5℃,接菌量2片(直径为4 mm的菌片),葡萄糖20 g/L,马铃薯40 g/L,装液量30 m L/100 m L,摇床转速150 r/min,初始p H 5.5。优化后,云芝对酸性铬蓝K的脱色率可达95.94%。     

副球菌BW001的生理特性及其对吡啶的降解

从武钢焦化厂废水处理系统的活性污泥中筛选出1株吡啶高效降解菌BW001,经菌株生理特性研究和16S rRNA序列测定,其属于副球菌(Paracoccus sp.).BW001为革兰氏阴性,具有固氮作用,对头孢、卡那霉素和利福平具有抗性.用SDS碱裂解法从该菌株中提取到1个小质粒和2个大质粒,其中2个大质粒可被限制性内切酶EcoR Ⅰ,BamH Ⅰ、Hind Ⅲ单酶切.以吡啶为唯一碳、氮源,在投菌量为0.03 g/L、吡啶初始质量浓度为493.4 mg/L、温度为30℃、pH为6.5的条件下,BW001可在33.0 h内将吡啶完全降解,降解速率为16.16 g/(L·h),吡啶中50%～60%的氮转化为NH4 ,高浓度吡啶对BW001产生一定抑制,但菌株在适应后,对吡啶的降解速率更高;降解吡啶最适温度为30～35℃,最适pH为8.0.     

可用于水体污染控制的氨氮转化菌筛选及部分降解特性的实验研究

从南京禄口水产养殖基地淡水鱼塘取淤泥作为分离菌株的土源,采用选择性富集培养法,从中分离到能以硫酸铵为氮源的菌株7株,对7个菌株进行氨氮降解实验,它们氨氮转化率分别为14.8%、19.7%、53.4%、94.2%、29.1%、63.5%和41.7%,其中AN-4菌株的转化率最高且生长良好。通过AN-4菌株16S rRNA基因序列分析以及生理生化方法,鉴定此菌株为克雷伯氏菌属(Klebsiellasp.)。对菌株AN-4转化氨氮的特性及温度、pH值、氨氮初始浓度和菌株接种量对其氨氮转化率的影响研究,结果表明,菌株AN-4降解氨氮的最适条件为:温度为30℃和pH值为8.0;当氨氮初始浓度为30mg/L时,AN-4菌株在24 h内的氨氮降解率可达85%以上,且能耐受高达200 mg/L的氨氮浓度;AN-4活化菌液浓度为108cfu/mL,当接种量为3×106cfu/mL时,AN-4菌株在24 h内的氨氮降解率为87.75%。综合上述结果,符合淡水养殖水环境条件,说明AN-4菌株适合在水产养殖中应用,为将菌株AN-4应用于水产养殖环境修复提供了理论依据。     

耐盐性毒死蜱降解混合菌的构建及其降解特性

为明确蜡状芽孢杆菌(Bacillus cereus)混合菌株对毒死蜱的降解效果,采用正交实验的方法构建混合菌。以混合菌对毒死蜱的降解率和菌株的生长量为依据,利用单一因素实验考察了不同因素对混合菌降解毒死蜱的影响。结果表明:构建的混合菌中三菌株的体积比为1∶1∶3。在含80 mg/L毒死蜱的反应体系中,最适接菌量为8%(V/V),最适pH为7。在实验浓度下,混合菌对毒死蜱的降解符合一级动力学方程。混合菌对盐分有较高的耐受度,当反应液中氯化钠浓度在20～100 g/L之间时,混合菌对80 mg/L毒死蜱的降解率最高达61%。     

纤维素降解菌的筛选及其产酶特性

纤维素降解菌在纤维素类物质降解的过程中起着重要作用。通过滤纸条崩解和液态产酶实验,从腐烂的树叶中筛选出1株对纤维素有较强降解能力的菌株SY2,通过形态学特征以及生理生化反应,初步鉴定该菌株为荧光假单胞菌(Pseudomonas fluorescent)。产酶培养基及培养条件优化的实验结果表明:SY2的最佳产酶培养基为麸皮与秸秆粉的质量比1∶4、(NH4)2SO41%、pH8、固液比1∶2;最佳产酶条件为培养温度30℃、接种量7.5%、培养时间72 h;在酶液中添加Fe2+和VB12可使纤维素酶活力分别达到174.89μmol/(g.min)和165.99μmol/(g.min),提高了33.5%和26.3%。SY2对麸皮、滤纸的降解效果较好,降解率分别达到45.0%和33.3%。     

Modeling the spill in the Songhua River after the explosion in the petrochemical plant in Jilin

An explosion in a petrochemical plant in Jilin in the northeast of China on 13 November 2005 was responsible for the discharge of large quantities of benzene and nitrobenzene into Songhua River. This endangered the water supply of Harbin city and influenced the daily life for millions of people. The dispersion-advection equation was solved analytically and numerically and used to simulate the concentration of benzene and nitrobenzene in the Songhua River after the accident. Both solutions gave practically identical results. The main elimination process for both compounds was volatilization. The model results are quite close to the results obtained by measurements at monitoring stations. Arrival time of the pollutant wave, peak concentrations and end of the pollutant wave at Harbin and along the river were predicted successfully. The peak concentrations of nitrobenzene at Harbin were more than 30 times above the permissible limits for drinking water.     

焦化废水中细菌质粒的研究

细菌质粒中常带有一些可编码降解特殊有毒物质酶的基因,为了研究质粒对有毒物质CN^-的降解的意义,主要调查了焦化废水中好氧异养菌的质粒分布特点。从山西省焦化企业公司生化站、太原煤气公司焦化厂生化站中筛选出53株细菌,利用琼脂糖凝胶电泳法,采用GDS-8000型凝胶电泳分析仪进行拍照,同时测定各菌株降氰、降酚能力,CN^-采用异烟酸-毗唑啉酮法,酚采用4-氨基安替比林法测定。结果表明,质粒的存在与降氰力有一定的关系,但对降酚力的影响差异不显著。同时,通过对其中11^*号菌株进行了质粒转化和消除实验,证明质粒稳定,不可用十二烷基磺酸钠(SDS)消除掉,用E．cbli DHI作受体菌,用11^#菌株作供体菌。作转化实验,但由于种种原因,没有筛洗到转化子。     

Managing the relationship with the environment

This article describes the results of a survey carried out by the author's company on behalf of Rank Xerox. The objective was to assess attitudes towards environmental issues in both the public and private sector. Although there were some differences over priorities, both sectors agreed that development of environmental policies was essential to their future.     

水处理中含铁废料综合利用的研究进展

回顾了２０余年来我国在水处理中综合利用含铁废料的研究进展，分别评述了副产品硫酸亚铁制备絮凝剂ＰＦＳ的各种方法，废铁屑运用于内电解法水处理和其他含铁泥渣，废酸在水处理中的研究和应用现状，指出含铁废料综合利用中有待于进一步研究的若干问题。     

底泥修复中温度对微生物活性和污染物释放的影响

通过分析底泥中微生物的酶活性以及污染物的释放规律,探讨了温度对河道底泥生物修复的影响.结果表明,底泥中微生物的脱氢酶、脲酶和磷酸酶的活性随着温度的升高而显著增大,但温度对纤维素酶的活性影响较小.4 ℃和10 ℃时底泥中污染物的释放量和微生物的酶活性均较低,水质较稳定;20～37 ℃时底泥中污染物的释放量明显增加,微生物的新陈代谢能力有较大提高,水体的自净能力较强.在各种因素的综合作用下,20～30 ℃是进行底泥生物修复的适宜环境温度.此外,当pH为9.0以及添加葡萄糖时,底泥中微生物均表现出较高的脱氢酶活性.     

Effect of the pesticide lindane on the biomass of the microalgae Nannochloris oculata

This study assesses the growth of the microalgae Nannochloris oculata in the presence of lindane and the ability of N. oculata to remove lindane from media. Algal biomass increased with 0.1 and 0.5 mg L^?1 of lindane, and lindane concentrations in the media decreased. N. oculata removed 73% and 68.2% of lindane in the 0.1 and 0.5 mg L^?1 media concentrations, respectively. Algal biomass decreased to the level of the control at lindane concentrations greater than 2.5 mg L^?1, probably due to toxicity. N. oculata removed lindane from the media at concentrations lower than 1.0 mg L^?1. Thus, N. oculata may be useful for lindane bioremediation in contaminated aquatic systems.     

Isolation of the stable fraction (the core) of the humic acid

Humic acid consists of a recalcitrant (unhydrolysed fraction) (the core) and labile (hydrolysable fraction) fraction. Core-humic acid (core-HA) isolation was performed by treating source material with apolar and polar solvents (organic solvents+acid hydrolysis) before alkaline extraction. Leonardite, soil Ah horizont and dry blood were chosen for this study because of their different origin and degree of humification. Chemical analysis (elemental analysis, total acidity, E(4):E(6)), spectroscopic analysis (DRIFT and (1)H NMR), and complete mass balance were used to investigate the effect of purifying humic acids. The results obtained showed that purification produced a slight modification of Leonardite humic acids as was expected for these highly humified organic matrices. On the other hand, about 500 g kg(-1) of soil humic acids were lost by purification. The fractions lost mainly consisted of carbohydrates. Dry blood showed the presence of humic acids that contrasted with its origin, thus indicating the limitations of the common analytical methods used for HA extraction. Nevertheless, in practice, purification caused the complete disappearance (914 g kg(-1) of HA was lost) of these HAs. The results obtained in this work suggest that the HA fraction isolated (named core-HA) effectively represents the HA structure proposed by the existing literature, since the purification proposed was able to eliminate the adsorbed organic molecules (interference materials) coating the HA structure.     

Attempts to probe the ozone layer and the ultraviolet-B levels of the past

To get a proper perspective on the current status of atmospheric ozone, which protects the biosphere from ultraviolet-B (UV-B; 280-315 nm) radiation, it would be of value to know how ozone and UV-B radiation have varied in the past. The record of worldwide ozone monitoring goes back only a few decades, and the record of reliable UV-B measurements is even shorter. Here we review indirect methods to assess their status further back in time. These include variations in the Sun's emission and how these affect the atmosphere, changes in the Earth's orbit, geologic imprints of atmospheric ozone, effects of catastrophic events such as volcanic eruptions, biological proxies of UV-B radiation, the spectral signature of terrestrial ozone in old recordings of star spectra, and the modeling of UV-B irradiance from ozone data and meteorological recordings. Although reliable reconstructions do not yet extend far into the past, there is some hope for future progress.