微生物和酶在降解环境有机污染物中的应用

介绍了生物修复有机污染的土壤和水体的研究进展,对微生物和酶处理的技术进行了详细讨论。降解有机物的微生物以白腐真菌为代表,可有效降解多环芳烃;降解有机物的酶以过氧化物酶和水解酶为代表,分别能够降解芳香族化合物和有机农药。     

1株铜绿假单胞菌对芘的降解特性及代谢途径

多环芳烃（PAHs）因其具有"三致"作用对生态系统产生潜在威胁.微生物降解是多环芳烃降解的主要途径之一,筛选出能高效降解多环芳烃的菌株是微生物修复技术的关键.本文采用富集培养的方法从多环芳烃污染的污泥中分离到1株以芘为唯一碳源的菌株LX2,经形态观察、生理生化和16S rDNA鉴定,LX2属于铜绿假单胞菌（Pseudomonas sp.LX2）.菌株在含芘浓度为50 mg·L^-1的无机盐液体培养基中培养21 d对芘的降解效率达32.1%.经GC-MS分析发现,Pseudomonas sp.LX2降解芘的中间代谢产物主要有4,5-二氢芘、2''-羟基苯丙酮、苯酚、原儿茶酚.基于鉴定的代谢产物得出芘通过"萘"和"邻苯二甲酸"两种不同的途径被铜绿假单胞菌（Pseudomonas sp.LX2）降解.     

嗜盐高效降酚菌株Halomonas sp.H17的筛选及降解苯酚特性

从巴丹吉林沙漠盐湖沉积物中分离获得1株在高盐环境下高效降解苯酚菌H17.分析了H17生理生化特性、16S rDNA基因序列、苯酚降解特性及动力学,结果表明,H17属于盐单胞菌属(Halomonas sp.),能在0～20%的盐度下有效降解苯酚,每升外加适量的碳源(葡萄糖浓度0.8 g)和复合氮源(KNO_3 1 g、NH_4Cl 5 g、酵母提取物0.2 g和胰蛋白胨0.2 g)能够促进H17的生长及降解苯酚能力.在温度为30℃、pH 7～8、盐度5～10%的条件下,H17均能高效降解苯酚,最高降解率可达到88.5%.该菌株降解苯酚动力学符合Halane模型,经拟合其生长参数为μ_(max)=0.31 h~(-1),K_S=191.63 mg·L~(-1),K_i=683.05 mg·L~(-1).研究显示H17具有在高盐环境下降解和耐受苯酚的能力,同时对环境有较强的适应性,体现出其在高盐含酚废水实际处理中具有良好的应用价值.     

Biofiltration of the antibacterial drug sulfamethazine by the species Chenopodium quinoa and its further biodegradation through anaerobic digestion

The biofiltering capacity, distribution patterns and degradation of the antimicrobial sulfamethazine(SMT) by halophyte Chenopodium quinoa under hydroponic conditions and its further biodegradation through anaerobic digestion were evaluated. C. quinoa was cultivated for a complete life cycle under different concentrations of SMT(0, 2 and 5 mg/L) and sodium chloride(0 and 15 g/L). C. quinoa is able to uptake and partially degrade SMT. The higher the SMT concentration in the culture medium, the higher the SMT content in the plant tissue. SMT has different distribution patterns within the plant organs, and no SMT is found in the seeds.Dry crop residues containing SMT have a great potential to produce methane through anaerobic digestion and, in addition, SMT is further biodegraded. The highest specific methane yields are obtained using crop residues of the plants cultivated in the presence of salt and SMT with concentrations between 0 and 2 mg/L.     

Characteristics of microorganisms isolated from technogenic soils of the Kama region

Microorganisms capable of degrading monocyclic and polycyclic aromatic hydrocarbons and several chlorinated aromatic compounds were isolated from soils polluted with industrial waste from chemical plants. They were identified as representatives of the genera Pseudomonas, Flavobacterium, Alcaligenes, Rhodococcus, Microbacterium, Cellulomonas, Arthrobacter, and Brevibacterium. Among them, bacteria capable of utilizing xenobiotics in a wide range of ambient temperatures and pH and in the presence of high sodium chloride concentrations were revealed.     

Burkholderia sp.FDS-1降解硝基苯酚类化合物的特性研究

从长期受农药污染的土壤中分离到1株高效杀螟硫磷降解菌株Burkholderia sp.FDS^-1,它能以3-甲基-4-硝基苯酚(MNP)为唯一碳源和氮源进行生长.该菌能在9h内将0.6mmol.L-1MNP完全转化成邻甲基对苯二酚(MHQ),并能继续降解MHQ.该菌降解MNP的最适温度和pH分别为30℃和7.0,菌株降解MNP的速率和起始接种量呈正相关.降解MNP的酶为诱导酶.     

不同氧化还原条件下氯乙烯的微生物脱氯

氯乙烯是土壤和地下水中存在的污染物,其去除的有效途径之一为微生物降解.本研究在温度20℃、氯乙烯初始浓度100μmol/L条件下,对不同氧化还原条件下四氯乙烯、cis-二氯乙烯及一氯乙烯的微生物降解进行了实验.结果表明,在铁还原和碳酸氢盐存在条件下,四氯乙烯以0.26/d和0.31/d的速率分别脱氯为三氯乙烯和cis-二氯乙烯.在脂肪酸存在条件下,四氯乙烯、cis-二氯乙烯和一氯乙烯均完全脱氯为乙烯,但后两者脱氯速率(0.04/d)明显低于前者(0.57/d).在反硝化、锰还原及硫还原条件下,不同取代氯乙烯降解均不明显.当环境温度降至12℃,脱氯菌活性降低,但氯乙烯完全脱氯还原过程仍可发生.     

Anaerobic phenanthrene biodegradation with four kinds of electron acceptors enriched from the same mixed inoculum and exploration of metabolic pathways

Anaerobic phenanthrene biodegradation enriched process was described in detail. The enriched bacterial communities were characterized under four redox conditions. The enriched archaeal communities were stated under high percentage conditions. Relatively intact pathways of anaerobic phenanthrene biodegradation were proposed. Polycyclic aromatic hydrocarbons (PAHs) are widespread and persistent contaminants worldwide, especially in environments devoid of molecular oxygen. For lack of molecular oxygen, researchers enhanced anaerobic zones PAHs biodegradation by adding sulfate, bicarbonate, nitrate, and iron. However, microbial community reports of them were limited, and information of metabolites was poor except two-ring PAH, naphthalene. Here, we reported on four phenanthrene-degrading enrichment cultures with sulfate, bicarbonate, nitrate, and iron as electron acceptors from the same initial inoculum. The high-to-low order of the anaerobic phenanthrene biodegradation rate was the nitrate-reducing conditions>sulfate-reducing conditions>methanogenic conditions>iron-reducing conditions. The dominant bacteria populations were Desulfobacteraceae, Anaerolinaceae, and Thermodesulfobiaceae under sulfate-reducing conditions; Moraxellaceae, Clostridiaceae, and Comamonadaceae under methanogenic conditions; Rhodobacteraceae, Planococcaceae, and Xanthomonadaceae under nitrate-reducing conditions; and Geobacteraceae, Carnobacteriaceae, and Anaerolinaceae under iron-reducing conditions, respectively. Principal component analysis (PCA) indicated that bacteria populations of longtime enriched cultures with four electron acceptors all obtained significant changes from original inoculum, and bacterial communities were similar under nitrate-reducing and iron-reducing conditions. Archaea accounted for a high percentage under iron-reducing and methanogenic conditions, and Methanosarcinaceae and Methanobacteriaceae, as well as Methanobacteriaceae, were the dominant archaea populations under iron-reducing and methanogenic conditions. The key steps of phenanthrene biodegradation under four reducing conditions were carboxylation, further ring system reduction, and ring cleavage.     

含氮生物降解促进剂对土壤吸附正十六烷的影响

选用正十六烷模拟润滑油,通过振荡平衡实验,考察了两种含氮脂肪酸型生物降解促进剂（甲基二乙醇胺油酸酯（MDEAO）和油酸二乙醇酰胺（ODEA））对水土体系中正十六烷吸附行为的影响。实验结果表明：正十六烷在水土体系中的有机质标化分配系数与土壤种类无关,与生物降解促进剂种类有关;土壤对正十六烷的吸附过程更符合Freundlich等温吸附模型;MDEAO的临界胶束浓度为2.0 mg/L,对土壤吸附正十六烷有一定的促进作用,ODEA的临界胶束浓度为0.7 mg/L,形成的胶束对正十六烷的增溶效果明显,促进了正十六烷在土壤中的解吸。     

一株耐盐柴油降解菌的分离鉴定及其降解性能

从某油田附近受石油污染土壤中分离出一株以柴油为惟一碳源的耐盐菌株LS1。通过对菌株的生理生化特性、菌体的形态观察及16S r DNA基因序列分析鉴定菌株LS1为假单胞菌属(pseudomonas)。该菌株可耐受的最高盐度(Na Cl)和柴油浓度分别为6%~8%和12 000 mg/L。菌株生长的适宜p H和温度条件分别为6.0~8.0和28~36℃。在盐度为6%、p H为7.0、温度为32℃、菌种投加量为10%的条件下,初始浓度为3 000 mg/L的柴油经6 d降解后,去除率可达78.3%,加入适量外加碳源葡萄糖和蔗糖,可使降解率分别提高至92%和90%左右。菌株LS1的耐盐机理可能是通过在细胞内积累甜菜碱以调节菌株细胞内外渗透压平衡。投加甜菜碱可提高耐盐菌LS1在高盐环境下对柴油的降解效率。