高效阿特拉津降解菌株DNSIO降解条件优化

从长期施用阿特拉津的寒地黑土耕层（0～10cm）土壤中筛选到一株能以除草剂阿特拉津为氮源生长的降解菌株,结合16SrRNA序列分析结果,将该菌株命名为Arthrobacter sp．DNSl0。在接种量为10。CFU／mL的条件下,菌株DNSl0在24h内对100mg／L阿特拉津的降解率为99．41％。单因子实验结果表明,菌株DNSl0适宜生长和降解的条件范围是：温度25～35＇12,pH值5．0～8．0,培养液盐度0．1％～2％,对阿特拉津最大耐受浓度可达1200mg／L。正交实验法进一步表明,该菌株保持较好生长及降解能力的最优方案是温度30℃,pH值7．5,培养液盐度0．5％。影响其降解能力的环境因素的主次顺序依次是：温度〉盐度〉pH值。     

Rapid and Sensitive LC/MS/MS Direct Injection Method for the Determination of Trace Level Corexit EC9500A Oil Dispersant in Seawater

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) method for the determination of trace dioctyl sulfosuccinate (DOSS) concentrations in seawater samples has been established. The method is well suited to aquatic environment impact monitoring following application of the dispersant Corexit EC9500A. Linearity of the method was demonstrated down to 0.05 ng/mL^?1 (0.05 µgL^?1) DOSS in seawater, with a 2.4% relative standard deviation precision for preparation replicates. A US EPA method limit of detection of <0.02 ng/mL^?1 (<0.02 µgL^?1) was calculated and specificity was confirmed by monitoring of two qualifier ions at 291.1 m/z and 227.1 m/z. These transitions were confirmed by QToF analysis to be associated with the DOSS precursor ion at 421.2 m/z. For application to seawater samples and samples containing oil particulates, a practical and repeatable calibration range of 0.5 ng/mL^?1 (0.5 µgL^?1) to 25.0 ng/mL^?1 (25.0 µgL^?1) DOSS is reported. The method was shown to have excellent precision and accuracy, with a consistent ≤1.6% relative standard deviation for system suitability standards at 0.5 ng/mL^?1 (0.5 µgL^?1) and linear weighted (1/x) regression coefficients of determination ≥0.995. The surfactant nature of the analyte is discussed in relation to detection limit and loss of analyte. Speculation of a relationship between DOSS in association or aggregation with divalent cations, such as Ca²⁺ present in salt water and hard water, is suggested. The consequent effects on cell ionic balance and membrane function are discussed.     

Studies on Biodegradation of Nicotine by Arthrobacter sp. Strain HF-2

A nicotine-degrading bacterium, strain HF-2, was isolated from tobacco waste-contaminated soil and identified as a member of Arthrobacter sp. based on morphology, physiological tests, 16S rDNA sequence and phylogenetic characteristics. At thermal denaturation test indicated that the G + C mol% of strain HF-1 was 63.5. The relationship between the growth of the isolate and the nicotine degradation suggested that strain HF-2 could utilize nicotine as sole sources of carbon, nitrogen and energy. Blue pigment was observed during the nicotine degradation by strain HF-2. The isolate grew well at 20 to 33°C, initial pH 6.5 to 8.0 and 0.5 to 2.0 g L^?1 of nicotine concentration in the nicotine inorganic salt media. The maximum growth and nicotine degradation occurred at 30°C, initial pH 7.0 and 0.7 g·L^?1 of nicotine concentration in media under natural incubation condition. Strain HF-2 could degrade 100% of nicotine under the optimized incubation conditions for 43 h. The concentrations of nicotine were monitored by high performance liquid chromatography. This study demonstrates Arthrobacter sp. strain HF-2 had a great ability to degrade nicotine, and it may be available for the application to the bioremediation of environments contaminated by tobacco waste.     

高盐度工业废水优势降解菌的生长特性及应用

从3处不同的污泥中筛选到4株对高盐度工业废水有较好降解效果的菌株A41、A45、TA2、XA3。通过生长特性研究确定出4株菌株的最佳温度、pH、盐度适应范围,A41分别为(35℃,7和2%~3%),A45分别为(35℃,6和0.5%~4%),TA2分别为(35℃,8和0.5%~4%),XA3分别为(45℃,7和6%~8%)。试验结果表明,当A41、TA2、XA3的接种量按1∶1∶1混合时,处理工业废水效果最好。3株混合菌株处理高盐度废水的最佳处理时间为24 h、COD去除率达到了50.5%;最佳pH为9,COD去除率达到了58.3%。     

大风量低浓度VOCs气体二次吸附浓缩净化技术开发

针对许多生产工艺过程的VOCs排放呈现出大风量、低浓度和间歇排放的特点,本研究以活性炭和异丙醇为例进行了一种针对低浓度气体的吸附加中温再生二次吸附净化工艺的研发。结果表明,在入口浓度约400 mg/m3时,活性炭在30℃和70℃的平衡温度之间存在约4%的吸附有效工作容量。对再生能耗对比发现,进口VOCs浓度越低,新工艺节能效果越明显。吸附穿透曲线表明,随着过滤风速的减小,穿透前能处理的风量随之增加。对于低浓度吸附净化过程,采用中温脱附可以有效浓缩有机气体,最大可达5.62倍。以上结果表明,对于低浓度吸附净化过程,采用中温脱附加二次吸附可起到经济有效地浓缩有机气体的作用。     

共基质对优势菌降解原油的作用研究

以长期被石油污染的土壤为菌源,用原油作为唯一碳源进行驯化后,反复筛选、分离得到降解原油的优势6株(SY1~SY6),研究了初级共代谢基质和无机离子对优良菌降解原油的影响;并对所筛选出的6株菌进行混合菌的实验。结果发现,初级共代谢基质葡萄糖和乙醇加入可促进各菌株对原油的降解程度;混合菌的降解效果没有单一菌的除油效果好。     

2种轮作模式对镉污染土壤修复潜力的比较

选取重金属Cd污染较严重的郴州矿区废弃农田土壤进行盆栽实验,以红叶甜菜-菊苣和菊苣-油葵作为研究对象,研究2种轮作模式对土壤重金属Cd的修复潜力。实验结果表明：3种作物在轮作期间生长状态良好且对重金属都表现出较强的耐性及吸收积累能力。在红叶甜菜-菊苣轮作模式中,甜菜和菊苣的地上部分对Cd的富集系数（BCF）分别为11.34和8.22;在菊苣-油葵轮作模式中,菊苣地下和地上部分对Cd的富集系数分别为14.14和16.32,成熟油葵各个部位的富集系数都大于1,其中,叶和果肉的富集系数分别为2.57和2.19。因此,对于重金属Cd轻、中度污染的土壤来说,甜菜-菊苣轮作模式对于Cd的富集效果要优于菊苣-油葵。总的来说,利用这3种作物两两轮作的轮作模式,能充分利用四季的气候特点,并能在不影响作物产量的前提下大大提高作物对重金属的提取总量。     

萘降解菌的筛选及其对多环芳烃的降解

从柴油污染土壤中筛选分离出一株萘降解菌N-3,进行了菌种鉴定及萘双加氧酶基因(nah)验证,并考察了该菌对不同种类多环芳烃(PAHs)的降解能力及降解过程中脱氢酶活性的变化。实验结果表明:该菌为铜绿假单胞菌(Pseudomonas aeruginosa),含有nah基因;当分别对液体培养基中质量浓度为50 mg/L的萘、菲、蒽、芘、芴降解84 h时,菌株N-3对萘、菲、蒽、芘、芴的降解率分别为28.81%,34.83%,36.65%,27.50%,23.47%。菌株N-3的脱氢酶活性与其对不同PAHs的降解率呈一定的正相关性。该菌不仅能有效降解萘,且对其他种类PAHs也有一定降解作用。     

土体剪切带的模拟与机理分析

采用修正剑桥模型,研究在平面应变条件下正常固结土剪切带的产生机理和剪切带形状的多样性。研究结果表明,剪切带是由材料的不均匀变形引起,并由试样局部应变能释放的冲击作用形成的;试样端部摩擦约束与试样内部初始缺陷都能够引起试样的不均匀变形进而诱发剪切带。分析了不同边界约束条件、初始缺陷设置方式及二者共同作用对剪切带形式的影响,平面应变条件下土体的剪切带有单一型、交叉型和多段型等3种形式,多段剪切带的发展具有先后顺序。