Comamonas sp. IDO2合成靛蓝的特性研究

利用吲哚降解菌丛毛单胞菌(Comamonas)IDO2转化吲哚合成靛蓝,优化靛蓝合成条件,并对合成产物进行分析.结果表明,菌株IDO2能够在苯酚、萘、苯和菲的诱导下转化吲哚合成靛蓝,在苯酚诱导时靛蓝的产量最高.采用表面响应法优化菌株合成靛蓝的条件:吲哚197.76mg·L~(-1),苯酚203.39 mg·L~(-1),酵母浸粉0.18%,在此条件下靛蓝的合成量为9.0 mg·L~(-1),与初始条件下的产量相比提高了104%.此外,考察了不同金属离子对菌株IDO2合成靛蓝的影响,结果表明Ba~(2+)和Ca~(2+)对靛蓝的合成具有促进作用.采用液相色谱/飞行时间/质谱联用对菌株IDO2转化吲哚的产物进行定量和定性分析,发现合成产物主要为靛蓝和靛红,并依此提出了可能的反应途径.     

Biodegradation of 3,5-dimethyl-2,4-dichlorophenol in saline wastewater by newly isolated Penicillium sp. yz11-22N2

In this study,the performance of 3,5-dimethyl-2,4-dichlorophenol(DCMX) degradation by a screened strain was investigated.18 S r DNA and the neighbor-joining method were used for identification of the isolated strain.The results of phylogenetic analysis and scanning electron micrographs showed that the most probable identity of the screened strain should be Penicillium sp.Growth characteristics of Penicillium sp.and degradation processes of DCMX were examined.Fourier transform infrared spectroscopy of the inoculated DCMX solution was recorded,which supported the capacity of DCMX degradation by the screened Penicillium sp.Under different salinity conditions,the highest growth rate and removal efficiency for DCMX were obtained at p H 6.0.The removal efficiency decreased from 100%to 66% when the DCMX concentration increased from 5 to 60 mg/L,respectively.Using a Box–Behnken design,the maximum DCMX removal efficiency was determined to be 98.4%.With acclimation to salinity,higher removal efficiency could be achieved.The results demonstrate that the screened Penicillium sp.has the capability for degradation of DCMX.     

城市污水处理厂四环素抗性菌的筛选及其抗性基因分析

城市污水处理厂中抗生素抗性菌的富集和扩散对受纳水体及公共卫生安全造成严重的威胁.本研究从上海某城市污水处理厂活性污泥中筛选得到一株四环素抗性菌株TC-1,基于形态特征、生理生化特性和16S r DNA结果鉴定,菌株TC-1属于节杆菌属(Arthrobacter sp.).对节杆菌属菌株的全基因组分析表明,菌株TC-1含有多种抗生素抗性基因,包括四环素、氯霉素、大环内酯类和青霉素抗性基因.对比节杆菌属抗生素抗性基因的基因簇分析表明,这些抗性基因在节杆菌属中具有普遍存在性,表明其来源于相关菌株的遗传而非单个菌株的偶然获得.鉴于节杆菌属是潜在的病原性微生物,该结论可为废水生物处理系统中含抗生素抗性基因的致病微生物环境行为和风险评估提供参考.     

接种Penicilliumsp.和根际分泌物对土壤甲磺隆的协同降解研究

通过接种Penicillium sp.和模拟小麦根际环境的方法,研究了甲磺隆在Penicillium sp.和小麦根际分泌物协同作用下的生物降解特性.结果表明,根系分泌物丰富了土著微生物和外源微生物,对甲磺隆的降解具有显著的促进作用.接种Penicillium sp.的根际土壤中甲磺隆降解半衰期为8.6 d,其降解速率是接种Penicillium sp.的非根际土壤的1.8倍,是普通根际土壤的2.7倍.继续追加甲磺隆的试验表明,接种菌株Penicillium sp.对甲磺隆的降解具有可持续性.     

应用黑褐新糠虾测试织纹螺毒性的初步研究

尝试以黑褐新糠虾作为实验生物,研究了投喂不同毒性的织纹螺对糠虾存活的影响,并探讨了这一方法在织纹螺毒性测试中的应用.实验结果表明:有毒织纹螺能够导致黑褐新糠虾中毒死亡,糠虾的半致死时间与织纹螺的毒性之间有显著的相关性(R2=0.9943),在96 h内织纹螺对糠虾的半致死毒性为40.11 MU/g.利用黑褐新糠虾作为实验生物可以测试织纹螺样品毒性的高低,方法的检出限约为10.44 MU/g,与日本法定的河豚鱼食用安全标准(10 MU/g)相当.     

1株低温石油烃降解菌的分类鉴定及降解特性研究

从渤海油船泄漏区域的海底泥中筛选到1株能降解柴油的低温石油烃降解菌T7-2,初步鉴定为红平红球菌(Rhodococcus erythropolis).研究表明,利用工业乙醇无机盐培养基培养液体种子是适宜的,其最适温度和pH分别为15℃和7.8,工业乙醇最适加入量为0.5％,菌体浓度为10⁸ CFU/mL.接种人工海水烃降解培养基后,通过补加氮源 (NH₄)₂SO₄ 2.64　g/L、磷源Na₂HPO₄ 2.5 g/L和酵母粉 0.015 g/L后,15℃振荡培养7　d,降解率可以达到73.2％.该菌降解烷烃的范围很广泛,C12～C36均有不同程度的降解.     

Optimized production of a novel bioflocculant M-C11 by Klebsiella sp. and its application in sludge dewatering

The optimized production of a novel bioflocculant M-C11 produced by Klebsiella sp. and its application in sludge dewatering were investigated. The optimal medium carbon source,nitrogen source, metal ion, initial pH and culture temperature for the bioflocculant production were glucose, NaNO3, MgSO4, and pH 7.0 and 25°C, respectively. A compositional analysis indicated that the purified M-C11 consisted of 91.2% sugar, 4.6% protein and 3.9% nucleic acids（m/m）. A Fourier transform infrared spectrum confirmed the presence of carboxyl, hydroxyl,methoxyl and amino groups. The microbial flocculant exhibited excellent pH and thermal stability in a kaolin suspension over a pH range of 4.0 to 8.0 and a temperature range of 20 to 60°C.The optimum bioflocculating activity was observed as 92.37% for 2.56 mL M-C11 and 0.37 g/L CaCl2 dosages using response surface methodology. The sludge resistance in filtration（SRF）decreased from 11.6 × 1012 to 4.7 × 1012m/kg, which indicated that the sludge dewaterability was remarkably enhanced by the bioflocculant conditioning. The sludge dewatering performance conditioned by M-C11 was more efficient than that of inorganic flocculating reagents,such as aluminum sulfate and polymeric aluminum chloride. The bioflocculant has advantages over traditional sludge conditioners due to its lower cost, benign biodegradability and negligible secondary pollution. In addition, the bioflocculant was favorably adapted to the specific sludge pH and salinity.     

Biodegradation of pendimethalin by Bacillus subtilis Y3

A bacterium strain Y3,capable of efficiently degrading pendimethalin,was isolated from activated sludge and identified as Bacillus subtilis according to its phenotypic features and 16 S rRNA phylogenetic analysis.This strain could grow on pendimethalin as a sole carbon source and degrade 99.5%of 100 mg/L pendimethalin within 2.5 days in batch liquid culture,demonstrating a greater efficiency than any other reported strains.Three metabolic products,6-aminopendimethalin,5-amino-2-methyl-3-nitroso-4-(pentan-3-ylamino) benzoic acid,and 8-amino-2-ethyl-5-(hydroxymethyl)-1,2-dihydroquinoxaline-6-carboxylic acid,were identified by HPLC-MS/MS,and a new microbial degradation pathway was proposed.A nitroreductase catalyzing nitroreduction of pendimethalin to 6-aminopendimethalin was detected in the cell lysate of strain Y3.The cofactor was nicotinamide adenine dinucleotide phosphate(NADPH) or more preferably nicotinamide adenine dinucleotide(NADH).The optimal temperature and pH for the nitroreductase were 30℃ and 7.5,respectively.Hg~(2+),Ni~(2+),Pb~(2+),Co~(2+),Mn~(2+) Cu~(2+),Ag~+,and EDTA severely inhibited the nitroreductase activity,whereas Fe~(2+),Mg~(2+),and Ca~(2+) enhanced it.This study provides an efficient pendimethalin-degrading microorganism and broadens the knowledge of the microbial degradation pathway of pendimethalin.     

Characterization of phenanthrene degradation by strain Polyporus sp. S133

Polyporus sp. S133, a fungus collected from contaminated soil, was used to degrade phenanthrene, a polycyclic aromatic hydrocarbon, in a mineral salt broth liquid culture. A maximal degradation rate (92%) was obtained when Polyporus sp. S133 was cultured for 30 days with agitation at 120 r/min, as compared to 44% degradation in non-agitated cultures. Furthermore, the degradation was a ected by the addition of surfactants. Tween 80 was the most suitable surfactant for the degradation of phenanthrene by Polyporus sp. S133. The degradation rate increased as the amount of Tween 80 added increased. The rate in agitated cultures was about 2 times that in non-agitated cultures. The mechanism of degradation was determined through the identification of metabolites; 9,10-phenanthrenequinone, 2,2’-diphenic acid, phthalic acid, and protocatechuic acid. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Polyporus sp. S133 were detected during the incubation. The highest level of activity was shown by 1,2-dioxygenase (187.4 U/L) after 20 days of culture.     

微囊藻毒素降解菌的分子鉴定和特性研究

在成功筛选出1株能够降解微囊藻毒素(Microcystins,MCs)菌株的基础上,利用16S rDNA的PCR扩增和序列分析对其进行了分子鉴定。由BLAST序列比对及进化树分析可将该菌株定属至鞘氨醇单胞菌USTB-01(Sphingopyxissp.USTB-01),这是我国首次筛选出高效降解MCs的鞘氨醇单胞菌。在鞘氨醇单胞菌USTB-01降解MC-RR和MC-LR活性研究方面发现,温度30℃和pH7.0条件下该菌降解MCs的速率最大,日均降解MC-RR和MC-LR分别达到了23.4mg/L和7.9mg/L,在进一步去除水体中的MCs的基础和应用研究方面都具有非常重要的意义。