铜绿假单胞菌胞内酶粗提液对十溴联苯醚的降解

探讨了铜绿假单胞菌粗酶液对十溴联苯醚(BDE-209)的降解特性,结果表明,该菌株胞内酶在12 h内对1 mg.L-1的BDE-209降解率达到了69.22%,温度、pH值、酶蛋白浓度及底物BDE-209浓度均会影响胞内酶粗提液对BDE-209的降解效率.当BDE-209浓度为1 mg.L-1时,BDE-209适宜的酶促降解条件为:温度30℃,反应pH值7.5,且降解率随着酶浓度的增加而增大.胞内酶对BDE-209的降解过程符合一级动力学反应模型,底物浓度为1 mg.L-1时降解速率最快,半衰期为6.9 h.胞内酶降解BDE-209符合高浓度底物抑制的酶促反应类型,其基本降解动力学参数为rmax=0.133 mg.(L.h)-1,Km=0.642mg.L-1,Ki=1.558 mg.L-1.     

Assessment of a process to degrade metal working fluids using Pseudomonas stutzeri CECT 930 and indigenous microbial consortia

The development of a novel biological process to treat metal working fluids (MWFs)-containing effluents at bioreactor scale was pursued in this work. The bacteria Pseudomonas stutzeri CECT 930 was investigated for the first time as an alternative agent for MWF degradation. An adequate medium design and mixing and aeration system, as well as an appropriate microorganism proved to be crucial for reaching high levels of degradation by P. stutzeri and by an indigenous consortium (about 70% and 50% of reduction in total petroleum hydrocarbon content in less than 2 wk, respectively). Additionally, as there is no information in literature trying to kinetically characterize an MWF-polluted effluent degradation process, all the experimental data were fitted to logistic and Luedeking and Piret models, that allowed to elucidate the growth-associated character of the biodegradation process.     

生物膜处理高含油废水及膜表面微生物群落特性研究

利用单一铜绿假单胞菌NY3生物膜在敞开体系中（非无菌条件下）处理石油废水,结果发现,生物膜可高效率去除高浓度含油废水中的油类物质.在2g/L含油水样中,连续运行25d,石油烃去除率可持续保持约91.1%.停止进水后,曝气可使生物膜活性恢复.自然环境中,配伍于NY3菌生物膜中的微生物主要有芽孢杆菌、假单胞菌和红球菌属,其中在实验室能够培养出来的微生物经16SrRNA鉴定分别属于红球菌属和芽孢杆菌属,经检测,2株菌均有高的石油烃降解效率.     

Immunotoxic effect of arsenic trioxide on Caenorhabditis elegans

A Pseudomonas aeruginosa–Caenorhabditis elegans pathogenesis model was utilized to assess immunotoxic effects of arsenic trioxide (As₂O₃). After 2 h of As₂O₃ exposure, 500 µmol L^?1 and 1 mmol L^?1 As₂O₃ treatment significantly decreased median survivals of C. elegans (10 h after L4/adult molt). However, 2 h of As₂O₃ exposure caused no significant changes in the survivals rates of C. elegans (2 h after L4/adult molt). Notably, a significant dose-related immunoenhancement was observed in C. elegans (2 h after L4/adult molt) after 12 h of arsenite exposure.     

草甘膦对同源假单胞基因工程菌代谢活性的影响

基于微量热法,研究两株基因缺失型斯氏假单胞杆菌对草甘膦的耐受毒性和降解作用,结果表明:草甘膦可以作为菌株的能量来源;草甘膦对P.stutzeri WM 581和P.stutzeri WM 567的半抑制浓度分别为47.47,43.26mg/L.两菌株对草甘膦均有较快的降解速率,其降解的半衰期约为9~17h,而草甘膦作为2类菌株生长过程中可以代谢的营养物质,其作为唯一碳源时的降解率(64%)要高于作为磷源时的降解率(43%).pH值与盐度对两菌株的生长有较大影响,草甘膦降解的较佳条件为:pH值为6,盐度低于0.5g/L.     

Pseudomonas flava WD-3对人工湿地中土著微生物量及酶活性的影响研究

从山东南四湖人工湿地的底泥中分离驯化出在低温条件下生长速率及代谢速率最高的一株菌,经形态特征、生理生化特性及16S r DNA序列分析鉴定,确定该菌株为黄假单胞菌(Pseudomonas flava),命名为Pseudomonas flava WD-3.同时,探索了在北方冬季条件下,该菌投加到人工湿地中在提高废水处理效率的同时,对湿地中土著可培养微生物类群数量和酶活性的影响.结果表明:随着Pseudomonas flava WD-3投加量的增加,人工湿地中可培养细菌、真菌、放线菌、硝化细菌及反硝化细菌的数量均产生了显著变化(p0.01).与对照组相比,湿地系统中可培养细菌、放线菌、硝化细菌及反硝化细菌数量最大分别增加了1.3、1.9、2.3、1.3倍,而可培养真菌数量最大减少了23.3%.土壤酶活性也随着Pseudomonas flava WD-3投加量的增加而增强,当Pseudomonas flava WD-3为水处理效果最佳投加量(6.00%)时,与对照组相比,过氧化氢酶、脲酶和脱氢酶活性最大增幅分别高达69.2%、41.3%和54.5%,蔗糖酶最大增加了2.3倍.研究表明,Pseudomonas flava WD-3在提高冬季人工湿地污水净化效果的同时,还能促进湿地土著可培养微生物的生长和酶的活性.     

Preparation and Biodegradation of Starch/Polycaprolactone Films

Starch granules were modified with trisodium trimetaphosphate (TSTP) and characterized by P³¹-NMR, FTIR and DSC. Seventy-micron films were prepared from modified starch and polycaprolactone blends by solvent casting technique. Three different types of films—PCL (100% polycaprolactone), MOD-ST/PCL (50% modified starch and 50% polycaprolactone blend) and NONMOD-ST/PCL (50% nonmodified starch and 50% polycaprolactone blends)—were prepared, and their thermal, mechanical, and morphologic properties were investigated to show the increased performance of PCL with the addition of starch and also the effect of modification. It was observed that with the addition of starch the Young's modulus of polycaprolactone was increased and became less ductile, whereas tensile strength and elongation at break values decreased. Biodegradation of these films was inspected under different aerobic environments with the presence of Pseudomonas putida, activated sludge, and compost. It was observed that whereas P. putida had almost no effect on degradation during 90 days, with the presence of activated sludge, considerable deformation of films was observed even in the first 7 days of degradation. In a compost environment, degradation was even faster, and all polymer films were broken into pieces within first 7 days of degradation and no film remained after 15 days.     

Pseudomonas lemoignei has five poly(hydroxyalkanoic acid) (PHA) depolymerase genes: A comparative study of bacterial and eukaryotic PHA depolymerases

Four polyhydroxyalkanoate (PHA) depolymerases were purified from the culture fluid ofPseudomonas lemoignei: poly(3-hydroxybutyrate) (PHB), depolymerase A (M _r , 55,000), and PHB depolymerase B (M _r , 67,000) were specific for PHB and copolymers of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) as substrates. The third depolymerase additionally hydrolyzed poly(3-hydroxyvalerate) (PHV) at high rates (PHV depolymerase;M _r , 54,000). The N-terminal amino acid sequences of the three purified proteins, of a fourth partially purified depolymerase (PHB depolymerase C), and of the PHB depolymerases ofComamonas sp. were determined. Four PHA depolymerase genes ofP. lemoignei (phaZ1,phaZ2,phaZ3, andphaZ4) have been cloned inEscherichia coli, and the nucleotide sequence ofphaZ1 has been determined recently (D. Jendrossek, B. Müller, and H. G. Schlegel,Eur. J. Biochem. 218, 701–710, 1993). In this study the nucleotide sequences ofphaZ2 andphaZ3 were determined.PhaZ1,phaZ2, andphaZ4 were identified to encode PHB depolymerase C, PHB depolymerase B, and PHV depolymerase, respectively.PhaZ3 coded for a novel PHB depolymerase ofP. lemoignei, named PHB depolymerase D. None of the four genes harbored the PHB depolymerase A gene, which is predicted to be encoded by a fifth depolymerase gene ofP. lemoignei (phaZ5) and which has not been cloned yet. The deduced amino acid sequences ofphaZ1–phaZ3 revealed high homologies to each other (68–72%) and medium homologies to the PHB depolymerase gene ofAlcaligenes faecalis T₁ (25–34%). Typical leader peptide amino acid sequences, lipase consensus sequences (Gly-Xaa-Ser-Xaa-Gly), and unusually high proportions of threonine near the C terminus were found in PhaZ1, PhaZ2, and PhaZ3. Considering the biochemical data of the purified proteins and the amino acid sequences, PHA depolymerases ofP. lemoignei are most probably serine hydrolases containing a catalytical triad of Asp, His, and Ser similar to that of lipases. A comparison of biochemical and genetic data of various eubacterial and one eukaryotic PHA depolymerases is provided also.Paper presented at the Bio/Environmentally Degradable Polymer Society—Second National Meeting, August 19–21, 1993, Chicago, Illinois.     

生物法处理油田采出水

用生物法处理石西油田采出水（简称采出水），通过中试试验考察了采出水的处理效果。试验结果表明：处理水量为2．5m^3／h、进水中COD小于600mg／L时，出水中COD一般稳定在90～120mg／L，COD去除率一般在70％以上；出水中挥发酚、油质量浓度分别为0．007～0．219，0．1～1．8mg／L，达到GB8978--1996（污水综合排放标准》中的二级标准。对油去除效果较好的SYB，SYG，SYJ均为杆状单生鞭毛铜绿假单胞菌。