初级基质对降解菌Pseudomonasputida共代谢苯扎贝特的影响

通过对3,5-二硝基水杨酸（DNS）法测定还原糖含量各影响因素的筛选,优化确定了显色时间8min,稳定时间10min,最佳波长490nm下进行吸光度测定的检测方法;分析分别以葡萄糖和麦芽糖作为外加碳源时,降解菌Pseudo—monasputidaB-31的生长情况和共代谢降解典型药物苯扎贝特（BZF）的过程。结果表明,降解菌只有在外加碳源的条件下才可正常生长,而且其在葡萄糖环境中生长得更好;拟合得到的葡萄糖、麦芽糖和BZF代谢动力学结果显示,葡萄糖对BZF去除的促进作用更为明显,同时从葡萄糖培养基中降解菌所提取的酶比活力要高于麦芽糖培养基,分析原因可能是葡萄糖所诱导的降解菌关键酶活力更强,而且还可能会产生不同的蛋白质点位。     

硝化细菌对碘普罗胺的降解及作用机制

将富含硝化细菌的驯化污泥投放于培养基中,以碘普罗胺(IOPr)为处理对象,研究硝化细菌对IOPr的降解促进作用情况。结果表明,富集培养的硝化细菌能有效地促进IOPr的降解,最佳反应条件为:温度30℃,pH 8.0~8.5,初始投加浓度为10 mg/L,同时在硝化细菌存在条件下,IOPr的5 d降解率可达84.1%。IOPr的生物降解属于共代谢机制,向培养基中加入葡萄糖、可溶性淀粉和麦芽糖,可以显著提高IOPr的降解去除率;在投加500 mg/L葡萄糖作为外加碳源时,硝化细菌对IOPr的3 d降解率可达60.3%。     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌,进行了系列降解实验.不同温度的降解实验表明,在4～20℃的实验温度范围内,AT菌能够降解代谢污染质,并随温度的升高,降解能力增强.20℃时降解率为38.84%;AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力,且在以阿特拉津为惟一氮源(外加碳源)条件下的降解效果最好,此时的降解率为30.39%.     

一株对硝基苯酚降解菌的筛选鉴定及其降解特性

从受甲基对硫磷污染的土壤中分离筛选得到一株能够以对硝基苯酚(PNP)作为唯一碳源、氮源生长的菌株,命名为TM.经16S rDNA序列分析初步鉴定该菌株为节杆菌(Arthrobacter).考察了该菌株在PNP浓度、盐度(NaCl)、pH、外加碳源(葡萄糖)、外加氮源等因素下对PNP降解特性的影响.结果表明:该菌株对PNP的最大耐受质量浓度为300 mg/L,并在降解的过程中生成NO2-该菌株的耐盐能力可达0.30％(质量分数),其最佳pH为8.在此pH下,200 mg/L的PNP在16h时即可被完全降解,添加0.30％(质量分数)的葡萄糖可使生物量和降解速率达到最大,牛肉膏作为外加氮源最有利于该菌株对PNP的降解.     

壬基酚降解菌产酶条件的优化

通过单因素试验和正交试验确定了实验室保藏的壬基酚降解菌株沙雷氏菌(Serratiasp.LJ)的最佳产酶条件:以壬基酚、硫酸铵为碳源、氮源,培养基初始pH为6.8,培养温度为30℃,种子活化时间为24h,接种量为3%(体积分数)。在此条件下培养72h后,最高酶活力为1.314IU/mL,是优化前的1.77倍。     

纤维素降解菌的筛选及其产酶特性

纤维素降解菌在纤维素类物质降解的过程中起着重要作用。通过滤纸条崩解和液态产酶实验,从腐烂的树叶中筛选出1株对纤维素有较强降解能力的菌株SY2,通过形态学特征以及生理生化反应,初步鉴定该菌株为荧光假单胞菌(Pseudomonas fluorescent)。产酶培养基及培养条件优化的实验结果表明:SY2的最佳产酶培养基为麸皮与秸秆粉的质量比1∶4、(NH4)2SO41%、pH8、固液比1∶2;最佳产酶条件为培养温度30℃、接种量7.5%、培养时间72 h;在酶液中添加Fe2+和VB12可使纤维素酶活力分别达到174.89μmol/(g.min)和165.99μmol/(g.min),提高了33.5%和26.3%。SY2对麸皮、滤纸的降解效果较好,降解率分别达到45.0%和33.3%。     

静态环境下阿特拉津的生物降解研究

从农药厂阿特拉津生产车间污泥中分离出菌种AT菌，进行了系列降解实验。不同温度的降解实验表明，在4～20℃的实验温度范围内，AT菌能够降解代谢污染质，并随温度的升高，降解能力增强。20℃时降解率为38．84％；AT菌在外加氮源、碳源及以阿特拉津为惟一碳源和氮源等条件时对农药污染质阿特拉津均具有降解能力，且在以阿特拉津为惟一氮源（外加碳源）条件下的降解效果最好，此时的降解率为30．39％。     

高效降解微囊藻毒素食酸戴尔福特菌USTB-04的培养与活性研究

主要针对筛选的高效降解微囊藻毒素(microcystins,MCs)的食酸戴尔福特菌USTB-04(Delftia acidovorans,DA菌)的培养方法进行了研究.结果表明,以葡萄糖、甘油和乙醇作为惟一碳源时,与氯化铵和尿素相比,酵母粉是支持DA菌生长的较好氮源.在以酵母粉作为惟一氮源时,与甘油和乙醇相比,葡萄糖是提高DA菌生长速度的较好碳源.进一步研究显示,以葡萄糖和酵母粉作为碳源和氮源时,可以支持DA菌的快速稳定生长,但在以甘油和酵母粉作为碳源和氮源时.培养出的DA菌降解MCs的比活性最高.此研究在培养高细胞浓度DA菌作为生物催化剂用于饮用水源中的MCs去除方面具有重要意义.     

石油降解菌XD-1产表面活性剂的性能

从含油废水中筛选分离到1株原油降解菌XD-1,鉴定为假单胞菌(Pseuomonas sp.).初步实验表明菌XD-1具有较强的产表面活性剂乳化原油的作用,对该菌的产表面活性剂性能进行了研究.实验证明,菌XD-1所产表面活性剂为脂肽类物质,菌在生长对数期产表面活性剂,表面活性剂的产生为生长相关型;充足的碳源是产表面活性剂的必需条件,菌利用原油为碳源时能持续大量地产表面活性剂;原油和尿素为产表面活性剂的最适碳源和氮源,菌XD-1产表面活性剂的最佳营养培养基组成为葡萄糖10 g,尿素4 g,磷酸二氢钾1 g,微量元素液4 mL,水1 L,pH 8.0.     

石油降解菌XD-1产表面活性剂的性能

从含油废水中筛选分离到1株原油降解菌XD-1,鉴定为假单胞菌（Pseuomonas sp.）.初步实验表明菌XD-1具有较强的产表面活性剂乳化原油的作用,对该菌的产表面活性剂性能进行了研究.实验证明,菌XD-1所产表面活性剂为脂肽类物质,菌在生长对数期产表面活性剂,表面活性剂的产生为生长相关型;充足的碳源是产表面活性剂的必需条件,菌利用原油为碳源时能持续大量地产表面活性剂;原油和尿素为产表面活性剂的最适碳源和氮源,菌XD-1产表面活性剂的最佳营养培养基组成为葡萄糖10 g,尿素4 g,磷酸二氢钾1 g,微量元素液4 mL,水1 L,pH 8.0.     

红三叶草根际区石油降解菌的筛选及降解性能

从石油污染的土壤红三叶草（nifoliumrepensLinn）根际修复区中分离筛选得到4株以原油作为惟一碳源和能源进行生长繁殖的高效石油降解菌。通过菌落形态、显微镜个体形态观察、生理生化鉴定以及菌株16SrDNA序列分析,初步鉴定4株优势降解菌分别为动性杆菌、藤黄微球菌、蜡状芽孢杆菌和短小芽孢杆菌。采用气相色谱／质谱（GC／MS）法分析4株混合菌对石油烃的降解性能。结果表明：在摇床培养条件下,混合菌54d对总石油烃的生物降解率达到90．50％,较对照高67．72％。随着生物降解时间的延长,石油组分中的正构烷烃、异构烷烃及环烷烃相对总量均呈减小趋势,而芳香烃和其他醇类、醛和酸类的相对含量则有所增加。     

可用于水体污染控制的氨氮转化菌筛选及部分降解特性的实验研究

从南京禄口水产养殖基地淡水鱼塘取淤泥作为分离菌株的土源,采用选择性富集培养法,从中分离到能以硫酸铵为氮源的菌株7株,对7个菌株进行氨氮降解实验,它们氨氮转化率分别为14.8%、19.7%、53.4%、94.2%、29.1%、63.5%和41.7%,其中AN-4菌株的转化率最高且生长良好。通过AN-4菌株16S rRNA基因序列分析以及生理生化方法,鉴定此菌株为克雷伯氏菌属(Klebsiellasp.)。对菌株AN-4转化氨氮的特性及温度、pH值、氨氮初始浓度和菌株接种量对其氨氮转化率的影响研究,结果表明,菌株AN-4降解氨氮的最适条件为:温度为30℃和pH值为8.0;当氨氮初始浓度为30mg/L时,AN-4菌株在24 h内的氨氮降解率可达85%以上,且能耐受高达200 mg/L的氨氮浓度;AN-4活化菌液浓度为108cfu/mL,当接种量为3×106cfu/mL时,AN-4菌株在24 h内的氨氮降解率为87.75%。综合上述结果,符合淡水养殖水环境条件,说明AN-4菌株适合在水产养殖中应用,为将菌株AN-4应用于水产养殖环境修复提供了理论依据。     

Diversity of biphenyl degraders in a chlorobenzene polluted aquifer

Biphenyl degrading bacteria (40 strains) have been isolated along a gradient of chlorobenzene pollution from an aquifer which did not contain any PCB to answer the question of how metabolic/catabolic abilities exist in ecosystems that have not been stressed with the relevant substrates is important for intrinsic bioremediations. Only few of the isolates were characterized by 16S rRNA gene sequence analyses as Pseudomonas species while the majority were Gram-positive, belonging to the order Actinomycetales and representing the genera Rhodococcus and Arthrobacter. The strains could grow on a variety of chlorobenzoates but no pattern of substrate usage and phylogeny or pollution gradient could be found. Strains which were able to grow on 2,5-dichlorobenzoate were often also able to use 3,4- and 3,5-dichloro- and 2,3,5-trichlorobenzoate or those using 2-chlorobenzoate could usually use 2,6-dichlorobenzoate as well. From that results, it is concluded that a highly diverse, basic metabolic activity for PCB degradation existed at this site despite the absence of PCB.     

Influence of herbicide glyphosate on growth and aflatoxin B1 production by Aspergillus section Flavi strains isolated from soil on in vitro assay

The effect of six glyphosate concentrations on growth rate and aflatoxin B₁ (AFB₁) production by Aspergillus section Flavi strains under different water activity (a_W) on maize-based medium was investigated. In general, the lag phase decreased as glyphosate concentration increased and all the strains showed the same behavior at the different conditions tested. The glyphosate increased significantly the growth of all Aspergillus section Flavi strains in different percentages with respect to control depending on pesticide concentration. At 5.0 and 10 mM this fact was more evident; however significant differences between both concentrations were not observed in most strains. Aflatoxin B₁ production did not show noticeable differences among different pesticide concentrations assayed at all a_W in both strains. This study has shown that these Aspergillus flavus and A. parasiticus strains are able to grow effectively and produce aflatoxins in high nutrient status media over a range of glyphosate concentrations under different water activity conditions.     

纤维素降解细菌筛选及降解特性分析

基于获得高效纤维素降解细菌的目的,通过LB培养基的培养以及刚果红培养基的筛选,从牛粪堆肥中筛选获得2株高效纤维素降解细菌。经鉴定,分别为枯草芽胞杆菌(Bacillus subtilis)和地衣芽胞杆菌(Bacillus licheniformis)。所筛选得到的菌种具有很高的滤纸降解能力,可在6d内使滤纸剧烈崩溃,振摇成均匀糊状;其中,地衣芽胞杆菌的羧甲基纤维素钠酶活峰值在发酵第4天达到峰值(237U/g)。     

高盐条件下硝基苯降解菌的分离及降解特性

在高盐条件下,从某制药厂曝气池的活性污泥中分离、筛选得到6株硝基苯高效降解菌,其中菌株N18在高盐条件下对硝基苯降解效率最高.经形态特征和生理生化特征分析,初步鉴定N18属于棒状杆菌属(Corynebacterium sp.).硝基苯降解试验表明,菌株最佳培养条件为30℃、培养基pH 7、摇床转速150 r/min.最佳培养条件下,当硝基苯初始质量浓度低于150 mg/L时,菌株培养72 h后硝基苯降解率达75％以上.当盐度为1％～3％时,盐度对硝基苯降解率的影响不明显,当盐度为10％时菌株生长微弱,因此N18属于中度耐盐细菌.     

Enrichment and isolation of endosulfan-degrading microorganism from tropical acid soil

Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzo-dioxathiepin-3-oxide) is a cyclodiene organochlorine currently used as an insecticide all over the world and its residues are posing a serious environmental threat. This study reports the enrichment and isolation of a microbial culture capable of degrading endosulfan with minimal production of endosulfan sulfate, the toxic metabolite of endosulfan, from tropical acid soil. Enrichment was achieved by using the insecticide as sole sulfur source. The enriched microbial culture, SKL-1, later identified as Pseudomonas aeruginosa, degraded up to 50.25 and 69.77 % of α and β endosulfan, respectively in 20 days. Percentage of bioformation of endosulfan sulfate to total formation was 2.12% by the 20th day of incubation. Degradation of the insecticide was concomitant with bacterial growth reaching up to an optical density of 600 nm (OD600) 2.34 and aryl sulfatase activity of the broth reaching up to 23.93 μg pNP/mL/hr. The results of this study suggest that this novel strain is a valuable source of potent endosulfan–degrading enzymes for use in enzymatic bioremediation. Further, the increase in aryl sulfatase activity of the broth with the increase in degradation of endosulfan suggests the probable involvement of the enzyme in the transformation of endosulfan to its metabolites.     

Alginate immobilized enrichment culture for atrazine degradation in soil and water system

An atrazine degrading enrichment culture, a consortium of bacteria of genus Bacillus along with Pseudomonas and Burkholderia, was immobilized in sodium alginate and was used to study atrazine degradation in mineral salts medium (MSM), soil and wastewater effluent. Sodium alginate immobilized consortium, when stored at room temperature (24 ± 5°C), was effective in degrading atrazine in MSM up to 90 days of storage. The survival of bacteria in alginate beads, based on colony formation unit (CFU) counts, suggested survival up to 90 days and population counts decreased to 1/5^th on 120 days. Comparison of atrazine degrading ability of the freely suspended enrichment culture and immobilized culture suggested that the immobilized culture took longer time for complete degradation of atrazine as a lag phase of 2 days was observed in the MSM inoculated with alginate immobilized culture. The free cells resulted in complete degradation of atrazine within 6 days, while immobilized cells took 10 days for 100% atrazine degradation. Further, immobilized cultures were able to degrade atrazine in soil and wastewater effluent. Alginate beads were stable and effective in degrading atrazine till 3rd transfer and disintegrated thereafter. The study suggested that immobilized enrichment culture, due to its better storage and application, can be used to degrade atrazine in soil water system.     

Characterization of phenol degradation by high-efficiency binary mixed culture

Background, aim, and scope  

Two new high phenol-degrading strains, Micrococcus sp. and Alcaligenes faecalis JH 1013, were isolated. The two isolates could grow aerobically in mineral salts medium containing phenol as a sole carbon source at concentration of 3,000 mg L⁻¹. It was found that the binary mixed culture of the two isolates possessed good potential for phenol removal.