N、P、Fe、Mn对亚历山大藻LC3生长的影响

利用正交试验研究了N、P、Fe、Mn四种物质对亚历山大藻LC3生长的影响,比较无机营养盐及微量金属元素对亚历山大藻LC3增殖影响的大小顺序,结果显示无机N对藻的生长有促进作用,882—2646μmol／L浓度时LC3生长较好,2646μmol／L下生长速率略快。无机P对亚历山大藻LC3生长的影响差异显著,一定浓度的P对LC3的生长有促进作用。Fe及Mn对藻生长均有促进作用,分别在3．5μg／L的Fe浓度下及18—36gg／L的Mn浓度下藻可获得较快的生长速率。四种元素对亚历山大藻LC3生长均有促进作用,各元素对生长影响的大小顺序依次为：P〉Mn〉N〉Fe。     

假单胞菌好氧降解四溴双酚A的特性

为了解四溴双酚A(TBBPA)的好氧降解特性,采用选择富集法从活性污泥中分离出一株能够高效降解四溴双酚A的菌株。根据其形态、生理生化特性及16S rDNA核苷酸序列分析,该菌株被鉴定为假单胞菌属(Pseudomonas sp.)。研究结果表明,该菌株可通过好氧共代谢方式实现四溴双酚A的降解,葡萄糖是四溴双酚A降解的最佳碳源,其最优降解条件为葡萄糖8 g/L,牛肉膏0.5 g/L,pH值为7.0,培养温度为35℃,摇床转速为150 r/min。在该条件下其生物降解过程符合一级动力学模型,6 d后的降解率高达95.6%。LC-MS结果表明,四溴双酚A在好氧降解过程中会生成异丙苯酚类物质。     

Isolation and characterization of mesotrione-degrading Bacillus sp. from soil

Dissipation kinetics of mesotrione, a new triketone herbicide, sprayed on soil from Limagne (Puy-de-Dôme, France) showed that the soil microflora were able to biotransform it.Bacteria from this soil were cultured in mineral salt solution supplemented with mesotrione as sole source of carbon for the isolation of mesotrione-degrading bacteria. The bacterial community structure of the enrichment cultures was analyzed by temporal temperature gradient gel electrophoresis (TTGE). The TTGE fingerprints revealed that mesotrione had an impact on bacterial community structure only at its highest concentrations and showed mesotrione-sensitive and mesotrione-adapted strains. Two adapted strains, identified as Bacillus sp. and Arthrobacter sp., were isolated by colony hybridization methods.Biodegradation assays showed that only the Bacillus sp. strain was able to completely and rapidly biotransform mesotrione. Among several metabolites formed, 2-amino-4-methylsulfonylbenzoic acid (AMBA) accumulated in the medium. Although sulcotrione has a chemical structure closely resembling that of mesotrione, the isolates were unable to degrade it.     

Origin and transport of U and Ra in riverine,estuarine and marine sediments of the Krka River,Croatia

Spatial distribution of ²³⁸U and ²²⁶Ra activities in sediment columns along the Krka River and estuary, were studied using gamma spectrometry. Markedly different ²³⁸U and ²²⁶Ra activities between riverine, estuarine and marine sediments were observed. Distribution of these radionuclides, as well as their anthropogenic and natural origin, was evaluated by activity measurements, taking into account sedimentation rates estimated by ¹³⁷Cs distribution in sediment columns.     

镰刀菌HJ01对对氯苯酚的降解特性

采用实验室分离的一株镰刀菌HJ01,以对氯苯酚(4-CP)为降解底物,以蔗糖为外加碳源,考察了蔗糖质量浓度、降解温度、初始pH对4-CP降解效果的影响,初步探讨了镰刀菌HJ01对4-CP的降解动力学和降解机理.实验结果表明:该菌株能以4-CP为惟一碳源和能源生长;在外加蔗糖为碳源,蔗糖质量浓度为3 g/L、降解温度为30℃、初始pH为8的条件下,50 mg/L4-CP能在6 d内被完全降解.以4-CP为惟一碳源和外加蔗糖下的降解动力学分别符合Haldane模型和一级动力学方程.     

Enrichment and Isolation of a Mixed Bacterial Culture for Complete Mineralization of Endosulfan

In the present study, we isolated three novel bacterial species, namely, Staphylococcus sp., Bacillus circulans–I, and Bacillus circulans–II, from contaminated soil collected from the premises of a pesticide manufacturing industry. Batch experiments were conducted using both mixed and pure cultures to assess their potential for the degradation of aqueous endosulfan in aerobic and facultative anaerobic condition. The influence of supplementary carbon (dextrose) source on endosulfan degradation was also examined. After four weeks of incubation, mixed bacterial culture was able to degrade 71.82 ± 0.2% and 76.04 ± 0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively, with an initial endosulfan concentration of 50 mg l^?1. Addition of dextrose to the system amplified the endosulfan degradation efficiency by 13.36 ± 0.6% in aerobic system and 12.33 ± 0.6% in facultative anaerobic system. Pure culture studies were carried out to quantify the degradation potential of these individual species. Among the three species, Staphylococcus sp. utilized more beta endosulfan compared to alpha endosulfan in facultative anaerobic system, whereas Bacillus circulans–I and Bacillus circulans–II utilized more alpha endosulfan compared to beta endosulfan in aerobic system. In any of these degradation studies no known intermediate metabolites of endosulfan were observed.     

碳源及反硝化芽孢杆菌强化低C/N比景观水体的生物脱氮

实验探讨了添加碳源及投加反硝化细菌对低碳氮比景观水体生物脱氮的影响。结果表明,有机碳源及B.subtilis FS05均能显著促进实验水体的生物脱氮作用,实验水体在28℃静置72 h后,乙醇添加组的TN、氨氮、硝酸盐及亚硝酸盐的去除率分别达到了62.7%、67.0%、69.8%和29.4%,而同样条件下,B.subtilis FS05投加组的去除率分别达到了66.9%、73.4%、66.0%和82.2%。从水质变化趋势可以看出,投加B.subtilis FS05能在更短时间内完成生物脱氮过程,其中,硝酸盐和亚硝酸盐去除速率最快,分别仅需要18 h和12 h。     

Fungal degradation of an acetolactate synthase (ALS) inhibitor pyrazosulfuron-ethyl in soil

Owing to reported phytotoxicity of some sulfonylurea class of herbicides in number of sensitive crops and higher persistence in soil, present study was conducted to isolate and identify pyrazosulfuron-ethyl degrading fungi from soil of rice field. Penicillium chrysogenum and Aspergillus niger, were isolated and identified from rhizospere soil of rice field, as potent pyrazosulfuron-ethyl degrading fungi. Degradation of pyrazosulfuron-ethyl by P. chrysogenum and A. niger, yielded transformation products/metabolites which were identified and characterized by LC/MS/MS. The rate of dissipation of pyrazosulfuron-ethyl was found higher in soil of rice field and soil inoculated with P. chrysogenum. This showed important route of degradation of pyrazosulfuron-ethyl by microbes apart from chemical degradation.     

Lead Solubilization and Accumulation by Two Strains of Pseudomonas Obtained from a Contaminated Alfisol's Effluent in Southwestern Nigeria

Two strains of Pseudomonas species (B₂ and D₅)selected from an array of lead solubilizing and accumulatingbacteria obtained from the effluent contaminated soil samples of abattery manufacturing factory were studied. Increase in pH between 4.0 and 6.0 favoured the growth of isolates: Peaklog₁₀ cfu mL^–1 values of 7.1, 7.5 and 8.5 wereobtained at pH 4, 5 and 6, respectively.Cell bound lead concentrations for B₂ (0.34 mg mL^–1)and D₅ (0.30 mg mL^–1) obtained by direct contact withPbs were greater than lead concentrations of 0.89 and 0.25 mg mL^–1 for B₂ and D₅, respectively,obtained in dialyzed cultures. These cell bound lead concentration in undialyzed cultures were alsogreater than lead concentrations of 0.03 and 0.07 mg mL^–1 for B₂ and D₅ in culture supernatants. Glucose addition did nor improve lead accumulation in the isolates.Exploitation of such isolates for the biotreatment of lead ladeneffluent was conducted.     

羊肚菌菌丝体的培养

本文首次报道了羊肚菌菌丝在９种琼脂培养基、５种固体培养料种、７种液体培养液中的生长情况，获得了培养羊肚菌菌种的最佳配方和１种静置培养液体菌种的新技术。