镰刀菌HJ01对苯酚的降解性能

为了研究真菌对苯酚的降解能力,采用本实验室分离的一株镰刀菌HJ01,考察了外加碳源、降解体系初始pH、温度对HJ01菌体生长量和苯酚降解效果的影响,初步探讨了镰刀菌降解苯酚的动力学与机理。实验结果表明,该菌能以苯酚为惟一碳源生长,添加适量的蔗糖可促进HJ01菌体的生长及苯酚的降解。在蔗糖加入量为3g／L、降解体系初始pH为6．0、温度为30℃的最佳条件下,经HJ01菌处理4d后的质量浓度为420mg／L苯酚废水中的苯酚完全降解。镰刀菌的生长和苯酚降解动力学符合Andrews模型。     

Assessment of the exposure of two fish species to metals pollution in the Ogun river catchments, Ketu, Lagos, Nigeria

The concentrations of metals (Ca, Cd, Fe, Mn, Pb and Zn) were determined by flame atomic absorption spectrophotometry in water, sediments and fish samples in the Ogun river catchments, Ketu, Lagos, which is an important bird nesting, fishing and drinking water source. The results show that the southern tip bothering the Lagos lagoon is where the highest metal concentrations are found in the fish species (Tilapia sp. and Chrysichthys sp.), whereas the Agboyi creek segment near the lagoon with higher surrounding human population density recorded higher levels of metals in sediments and water samples. The two fish species accumulated different amounts of metals. However, the differences were not statistically different at p < 0.05. There is a significant correlation (p < 0.05) for Cd concentration in water. The concentrations of Pb in sampling points 3 and 4 as well as Cd, Mn and Fe in all six sampling points exceeds the World Health Organization (WHO) limits for drinking water. Levels of metals obtained for sediments are within the range reported for Nigeria’s river sediments. Based on this study, the human risks for heavy metals in the harvested fish species from the Ogun river catchments, Ketu, are low for now as the concentrations were below the recommended Food and Agriculture Organization (FAO) maximum limits for Pb (0.5 mg/Kg), Cd (0.5 mg/Kg), and Zn (30 mg/Kg) in fish.     

Hydrocarbon Utilization in Yeast Isolates Found to Grow in Association with Petroleum in a Polluted Ultisol of Midwestern Nigeria

The population counts of hydrocarbon-utilising yeasts weremonitored at six sampling stations in the Benin City municipalarea over a four-week period. Although the population countswere relatively constant in each locality, the highest countsoccurred in areas heavily polluted by domestic and industrialeffluents. A total of thirty-five hydrocarbon-degrading yeastswere isolated from soil at the sampling stations usingn-hexadecane as sole carbon source. The isolates were identifiedas belonging to the genera Candida (27 strains), Endomycopsis (4 strains). All the organisms grew on long-chainn-alkane, kerosene, diesel oil and crude oil but failed to growon short-chain n-alkane, aromatic and alicyclic hydrocarbons.Measurement of growth attributes of the isolates usingn-hexadecane, diesel oil and crude oil as substrates showed thatthe Candida species were better utilizers of hydrocarbonsubstrates relative to Endomycopsis and Schizosaccharomyces species.     

废纸造纸循环废水高效好氧菌的筛选和研究

利用平板分离方法,从废纸造纸封闭循环废水处理的生物接触氧化池中筛选出优势的高效菌株,采用形态学观察和生理生化试验发现主要由动胶菌属(Zoogloea sp.)和假单胞菌属(Pseudomona sp.)组成。用吸光光度法,确定其最佳生长时间。通过平行对比实验,在不同时间取样测定COD值,比较得出高效菌对废纸造纸循环废水的处理能力远高于普通菌。     

辛硫磷降解菌XSP-1的分离、鉴定及其降解特性研究

从农药厂污泥中分离到1株能以辛硫磷为唯一碳源生长的细菌, 命名为XSP-1.根据其生理生化特征和16S rRNA基因序列相似性分析, 将该菌株初步鉴定为戴尔福特菌属(Delftia sp.). 该菌株能在7 h内完全降解100　mg/L的辛硫磷. XSP-1降解辛硫磷的最适pH为7.0, 最适温度为35℃, 降解速率与初始接种量呈正相关, 该菌株对甲基对硫磷、毒死蜱、杀螟硫磷也有较好的降解能力. 根据已报道有机磷农药降解基因mpd的保守序列设计引物, 未从该菌株中扩增到目标条带, 但是该菌株是否带有新的有机磷农药降解基因仍需要进一步研究.     

嗜热溶胞菌SY-14的基本特性研究

对从污泥堆肥中分离得到的具有溶胞能力的嗜热产芽孢杆菌SY-14进行了初步鉴定,并对其生长、产酶及溶胞特性进行了研究.根据菌株形态及16S rDNA测序结果,SY-14为土芽胞杆菌属(Geobacillus sp.).SY-14最适生长温度60℃左右,最适生长pH为6.0～7.0.SY-14培养上清液对完整和加热灭活后的微生物细胞都具有溶胞能力,6 h的细胞溶解率分别可达到70%和85%,上清液经过热处理后溶胞能力明显下降,表明溶胞能力主要来自于酶的作用.间歇培养过程中,SY-14培养上清液溶胞活性在对数生长期快速升高,进入稳定期前后达到最大,之后快速下降.SY-14培养上清液对受试的5株革兰氏阴性菌及部分革兰氏阳性菌都具有溶胞能力.     

拮抗菌B96-Ⅱ对芦笋枯萎菌的抑菌作用

为明确拮抗菌B96-Ⅱ对芦笋枯萎菌的抑制效果并探明其抑菌特性及方式,对经B96-11处理后芦笋枯萎菌的生长速率、液体电解质、电导率及菌丝重量等进行了测定研究.结果表明,在10~7～10~8 CFU/mL时,B96-Ⅱ对芦笋枯萎菌均有显著的抑制效果.连续3 wk室内观察发现,B96-Ⅱ对芦笋枯萎菌丝有持续的抑制作用,与对照比较抑制率为94.07%～88.98%.田问防治效果为93.40%.而农药多菌灵处理的防治效果仅为65.12%.拮抗菌B96-Ⅱ对芦笋枯萎菌的抑制方式主要为:(1)对孢子形成的抑制作用;(2)对孢子的溶解作用;(3)对菌丝生长的抑制作用;(4)对菌丝的致畸作用;(5)对菌体细胞的破损作用.B96-11处理后36 h,溶液总溶解性同体和电导率增高,而菌丝重量下降.图4表3参14     

丝孢酵母TX1降酚动力学研究及过程优化

针对自行分离筛选出的高效降酚丝孢酵母菌株TX1,通过不同初始浓度苯酚分批培养系列实验结果和分析,建立其降酚动力学模型,并在此基础上进行过程优化.结果表明,体系的生长动力学可以用Haldane方程描述,其参数分别为μmax=0.667 h-1,KS=51.14 mg/L,Ki=271.7 mg/L.参数说明TX1能较快地...     

一株耐铜细菌的鉴定及富集特性的研究

从铜矿污染区的土壤中分离纯化得到一株耐铜菌株USTB-E,最高耐受浓度为560 mg/L,通过形态观察,生理生化鉴定及16S rDNA序列分析技术鉴定出此菌株为假单胞菌。该菌的最适生长温度为35℃,pH为6.0,渗透压为0.3%。为了研究该菌耐铜机理,实验对铜离子富集机理进行了动力学研究,研究结果表明,USTB-E菌对...