阿特拉津降解菌株AD111的分离鉴定及其降解特性

【背景】玉豆轮作过程中,玉米田中长残留除草剂阿特拉津易对下茬大豆作物产生不良影响。【目的】从黑龙江省安达市的农田土筛选一株能适应该土壤环境生长的阿特拉津降解菌并研究其降解特性。【方法】利用富集培养法,分离、筛选一株阿特拉津高效降解菌并结合外观形态、生理生化及16SrRNA基因序列测定对其进行鉴定,通过单一变量法设置不同的碳源、pH、温度和阿特拉津浓度,研究降解菌株最佳发酵及降解条件。【结果】得到一株在BSM-G中能够以阿特拉津为唯一氮源生长的高效阿特拉津降解菌AD111,鉴定为马德普拉塔无色小杆菌(Achromobacter marplatensis)。菌株AD111降解阿特拉津的最适温度为35℃,最适pH为8.0,最佳碳源为蔗糖,24 h内对浓度为50 mg/L的阿特拉津降解率达到99.7%,对300 mg/L的阿特拉津降解率达到81.9%。【结论】降解菌AD111具有较好的环境适应及阿特拉津降解能力,为解决黑龙江偏碱土壤中阿特拉津残留提供了良好的候选菌株。     

Burkholderia cepacia X4降解油脂特性研究

从长期受油污染的土壤中分离筛选得到的Burkholderia cepaciaX4菌株能高效降解油脂。该菌株降解油脂的最适温度和pH分别为30℃和7.0,菌株降解油脂时适宜的氮源为硫酸铵,适宜碳氮比为4∶1。共基质碳源的添加有利于生物量的迅速增加和油脂降解率的提高,添加适量的葡萄糖能使油脂降解率提高8%~10%。50mg/L Ca2 对菌株生长和油脂降解更有利。在橄榄油浓度高达20g/L条件下最大油脂降解率仍可达83%。在油脂浓度≤2500mg/L时,该菌对油脂的降解符合抑制动力学Monod方程。     

纤维素降解菌的筛选与复合菌系的初步构建

目的针对大庆地区土地盐碱化较严重,盐碱面积较大等现状,从大庆特征性盐碱地区土壤样品中分离出能够降解纤维素的菌株,为降解植物废料以及缓解土壤盐碱化改善土壤环境提供功能菌株。方法通过刚果红染色法初步筛得到具有纤维素降解能力菌株,进一步用比色法测定其纤维素降解率,同时测定菌株耐盐、耐碱、产酸性能,选择性能优良的3株菌作为纤维素降解菌复合菌系构建菌株,通过耐盐性、耐碱性和纤维素降解率实验测定复合菌系菌株最佳组合,进一步通过上述实验确定复合菌系菌株最佳混合比例。结果得到由DX-5和DX-9按照2∶3进行组合复合菌系纤维素降解率最高,达到87.96%,且具有较高的耐盐以及耐碱能力。结论通过实验得到纤维素降解菌的复合菌系,具有较高纤维素降解率以及改善土壤盐碱性能力。     

高效石油降解菌群的构建及对芳香烃化合物萘的协同降解性能

【背景】石油作为一类混杂有机化合物,一旦产生污染就会对人类和环境造成严重的危害。【目的】从新疆石油污染土壤中分离筛选石油降解菌,为石油污染土壤的生物修复提供数据支持及技术参考。【方法】以石油为唯一碳源,通过富集培养、筛选分离得到123株单菌,根据菌落形态挑选出30个不同形态菌株,通过16S rRNA基因序列确定其种属,构建系统发育树;通过原油降解实验筛选出高效石油降解菌,以芳香烃的标志化合物萘为唯一碳源筛选出高效降解菌株,并分别筛选可降解水杨酸、邻苯二酚的菌株。【结果】分离筛选出5株高效石油降解菌,降解率高于85%;萘、水杨酸和邻苯二酚降解菌株各获得一株,将3种菌株按照1:1:1的接种比例对萘进行降解,萘的降解率从单菌60.74%提升到89.40%,菌株间的分工协作可以提高有机物的降解效率。【结论】筛选得到的菌株丰富了石油降解微生物菌种库,不同微生物菌株之间的分工协作为石油污染物的降解提供了新思路,为进一步研究石油污染治理提供参考。     

蒙氏假单胞菌Pseudomonas monteilii对食用油脂的利用效率研究

筛选具有利用食用油脂功能的菌株,为废弃食用油脂的资源化应用开展基础性前期研究。利用油脂中性红平板筛选法筛选到1株具有脂类降解能力的菌株鉴定为蒙氏假单胞菌。通过菌株形态特征扫描、生理生化特性,进而利用分光光度法探索了该菌株最适温度、最适pH等生长条件。并研究其在最适生长条件下的生长曲线及其在不同油脂作唯一碳源条件下的生长情况。结果表明,该菌株生长的最适温度为28℃、最适pH值为7.0、最适盐度为2g/L,达到最大培养生物量的时间为7h。对玉米油、动物油、花生油、芝麻油、椰子油、橄榄油共7种食用油脂具有相应的利用能力。     

福美双农药降解菌的分离与筛选

本研究的目的是筛选出具有降解福美双功能的菌株,并对福美双的降解效果进行评价。通过选择性培养基的富集技术和梯度稀释法从不同烟叶样品和植烟土壤样品中分离筛选出311株农药降解菌株;通过摇瓶培养和高效液相色谱法从311个菌株降解菌中复筛得到5株降解菌。继续从降解福美双能力对5株菌株进行筛选,结果显示:5种菌株中FM84和FM197对福美双的降解率均达到了90%以上。采用16S r DNA序列分析结合细菌常规鉴定方法对菌株进行了初步鉴定,FM84为克雷伯菌属和FM197为肠杆菌属。研究表明,菌株FM84和FM197对福美双有较高并且稳定的降解能力。     

一株高效DEHP降解菌的分离、鉴定及其降解特性

【目的】分离得到高效的邻苯二甲酸二乙基己基酯(DEHP)降解菌。【方法】采用富集培养法筛选分离菌株,并对菌株进行驯化;通过PCR扩增得到其16S rRNA和gyrB基因序列,进行同源序列分析及分子系统发育树的构建,同时结合形态学观察和生理生化实验对菌株进行初步鉴定;采用高效液相色谱(HPLC)分析菌株对DEHP的降解特性。【结果】分离得到一株能以DEHP为唯一碳源和能源生长的菌株,命名为HS-NH1,初步鉴定其为戈登氏菌(Gordoniasp.)。菌株HS-NH1最适的生长和降解条件为30°C、pH 7.0,在此条件下,该菌株60 h内能够将浓度为500 mg/L的DEHP降解90%以上。高效液相色谱(HPLC)分析表明,菌株HS-NH1在降解DEHP过程中产生了一种重要的中间代谢产物——邻苯二甲酸。底物广谱性试验证明,菌株HS-NH1能够有效地利用多种常见的邻苯二甲酸酯(PAEs)与芳香族衍生物。【结论】筛选得到了一株DEHP降解菌Gordonia sp.HS-NH1,该菌降解效率高,具有良好的底物广谱性,在邻苯二甲酸酯类化合物的污染治理中将会有一定的应用潜力。     

染料脱色菌与芳胺降解菌的筛选及降解染料研究

从印染厂废水处理系统的曝气池中分离到17株对多种染料有较高脱色能力的细菌,其脱色率都在80%以上,但偶氮染料脱色后产生的中间产物多数为无色的芳香胺类化合物,大多数细菌不能将其进一步降解。为此,通过富集培养和梯度驯化又筛选到一株以对硝基苯胺为唯一碳、氮源的菌株J18,该菌株虽对染料脱色能力很弱,却能够降解芳香胺类化合物。将芳香胺降解菌J18与染料脱色菌H两菌株混合培养,在最适条件下,结果使染料的脱色率和芳胺降解率均到达90%和85%以上,从而达到了彻底降解染料的目的。     

可降解吡啶的全食副球菌B21-3的筛选鉴定及降解特性

【背景】吡啶作为一种难降解的有机污染物普遍存在于焦化、炼油、皮革和制药等行业的废水中,并对环境造成危害。【目的】治理废水中残留的有机污染物吡啶,筛选高效降解菌。【方法】采用富集培养和选择培养,以石家庄某污水处理厂的活性污泥为材料进行吡啶降解菌的筛选,通过形态特征、生理生化特性、(G+C)mol%测定及16S rRNA基因序列系统发育分析对筛选到的降解菌进行鉴定,并分析其对吡啶的降解特性。【结果】分离筛选到一株能以吡啶为唯一碳源和氮源生长代谢的降解菌B21-3,经鉴定该菌株为全食副球菌(Paracoccuspantotrophus)。菌株B21-3对吡啶的最适降解温度为32°C,最适降解pH为7.0,吡啶浓度为100mg/L时降解率为48.50%±0.02%;通过逐步提高吡啶初始浓度对菌株进行驯化,驯化后菌株可耐受较高浓度吡啶且吡啶降解率显著增加,吡啶浓度为100 mg/L时驯化后菌株B21-3对吡啶的降解率为90.26%±1.70%。驯化后菌株在含吡啶的无机盐平板上传代培养15代后,对吡啶的降解率为89.39%±2.03%。【结论】菌株B21-3具有较强的吡啶降解能力及降解稳定性,该菌株可作为吡啶污染水体生物修复的潜在资源。     

一株微囊藻毒素降解菌的筛选及鉴定

从蓝藻爆发期间的巢湖底泥中筛选微囊藻毒素降解菌,为水体中藻毒素-LR(MC-LR)污染的生物治理提供有效的菌源。以MC-LR为唯一碳氮源,利用富集驯化培养技术分离筛选MC-LR降解菌,并对其进行形态观察、生理生化实验及16S rRNA序列分析鉴定。从巢湖底泥中分离得到一株藻毒素-LR降解菌株M6,生理生化实验及分子鉴定结果均表明,该菌株为蜡状芽孢杆菌(Bacillus cereus)。分离出的MC-LR降解菌为蜡状芽孢杆菌,该菌株对MC-LR有较高的降解能力。     

苯系物降解菌Pseudomonas putida SW-3的筛选及其降解苯的研究

【目的】以苯、甲苯和苯乙烯为唯一碳源,从工业石油废水中筛选苯系物降解菌,分析其降解特性,探讨底物间相互作用对降解情况的影响。【方法】经生理生化和16S r RNA基因分析进行菌种鉴定,采用顶空气相色谱法测定苯系物含量,通过细胞的疏水性、乳化能力、排油圈及透射电镜观察分析菌株降解特性。【结果】经鉴定该菌为Pseudomonas putida,命名为SW-3菌株。最适降解条件下,单位菌体对苯、甲苯和苯乙烯的最大降解速率分别为0.072、0.035和0.019 g/(L·h),苯系混合物的总降解率达79.99%。底物降解实验表明,苯可促进甲苯和苯乙烯的降解,而苯乙烯则能抑制甲苯的降解。菌株的吸附、摄取和降解特性的研究发现,菌株SW-3在自身分泌的表面活性剂的协助下以耗能的方式运输苯。【结论】菌株SW-3具有产生表面活性剂和降解苯系物的能力,且底物间的相互作用能够显著影响菌株对不同底物的降解。     

Isolation and Characterization of Biosurfactant-Producing Bacteria from Oil-Contaminated Soil

Two biosurfactant-producing Pseudomonas aeruginosa strains (KISR C1 and KISR B1) were isolated from Kuwaiti oil-contaminated soil, which resulted from the Gulf War. The optimum environmental conditions that supported the growth and surfactant production of both isolates were examined. The two isolates differed in their biosurfactant-stimu-lating carbon source, nitrogen concentration, and the pH of the medium. C-1 isolate produced two types of rhamnolipids with a final concentration of 98.4?g/l after spiking the nitrogen-limited medium with 10?mg/ml olive oil. The other isolate (B-1) produced only one type of rhamnolipid (5.9?g/l) after spiking the medium with crude oil. The biosurfactant produced by this strain was found to be very effective in the emulsifica-tion of crude oil. The result suggests that this isolate can potentially be used to enhance bioremediation of oil-contamination and enhanced oil recovery.     

一株蒽降解细菌的分离及降解特性研究

【目的】从盐碱土壤中筛选蒽降解菌株并分析其降解特性。【方法】采用极度稀释结果流式细胞检测法筛选分离纯化菌株,通过16S rRNA基因序列分析对菌株进行初步鉴定,采用气质联用仪(GC-MS)分析蒽的降解特性。【结果】从盐碱土壤中筛选出一株高效蒽降解菌株。经过16S rRNA基因序列分析,鉴定该菌株为Demequina salsinemorus BJ1。菌株可以利用蒽作为唯一碳源生长,降解率可达92%。在一定浓度范围内,随着蒽浓度的降低,细菌生长速率变快,降解率升高。添加外加碳源后,细菌生长速率明显变快,而对蒽降解率变低。对萃取中间代谢产物的质谱分析表明,降解蒽的中间代谢产物主要有9,10-anthracenedione (9,10-蒽醌)和Phthalic acid (邻苯二甲酸)等,说明它可能通过邻苯二甲酸途径降解蒽。【结论】筛选得到一株新的耐盐碱蒽降解菌,该菌降解效率高,对修复石油污染的土壤有一定的现实意义。     

制革废水中壬基酚聚氧乙烯醚降解菌的分离及特性

从长期受壬基酚聚氧乙烯醚污染的制革废水中采集水样,通过富集培养的方法从中筛选到一株可以壬基酚聚氧乙烯醚为唯一碳源生长的降解菌OPQa3。通过形态学特征观察和生理生化试验,结合16S rRNA基因序列分析,初步鉴定菌株OPQa3属于短波单胞菌属Brevundimonas sp.,其16S rRNA基因序列与Brevundimonas diminuta(EU434566.1)的相似性最高(99%)。降解菌OPQa3的生长周期为24 h;以2%的量接种菌株OPQa3,保证最终OD600=0.70,于746 mg/L的壬基酚聚氧乙烯醚培养基中,120 h内的降解率可达84.5%,菌OPQa3生长的最佳温度为30°C,最适pH值在7左右。降解性质粒检测结果表明,控制菌株OPQa3降解壬基酚聚氧乙烯醚的基因位于质粒上。     

Isolation and characterization of lipid-degrading Bacillus thermoleovorans IHI-91 from an icelandic hot spring

An efficient lipid-degrading thermophilic aerobic bacterium was isolated from an icelandic hot spring and classified as Bacillus thermoleovorans IHI-91. The aerobic bacterium grows optimally at 65°C and pH 6.0 and secretes a high level of lipase (300 U l⁻¹). The newly isolated strain utilizes several lipids such as palmitic acid, stearic acid, lanolin, olive oil, sunflower seed oil, soya oil, and fish oil as sole carbon and energy source without an additional supply of growth factors. The degradation of about 93% of triolein, which is present in olive oil, was observed after only 7 h of fermentation at a maximal growth rate of 1.0 h⁻¹. During growth at optimal conditions on yeast extract, the doubling time was only 15 min. Based on 16S rDNA studies, DNA–DNA hybridization and morphological and physiological properties, the isolate IHI-91 was identified as Bacillus thermoleovorans IHI-91 sp. nov. Because of its production of high concentrations of thermoactive lipases and esterases and the capability of degrading a wide range of lipids at high temperatures, the isolated strain is an ideal candidate for application in various biotechnological processes such as wastewater treatment. Received: August 25, 2000 / Accepted: September 26, 2000     

稠油降解菌的筛选及其对胶质降解作用

【目的】以胶质为唯一碳源,从中海油南堡35-2油田地层水中经富集培养,为海上油田稠油降解及提高稠油采收率研究奠定基础。【方法】利用富集培养和胶质平板法分离胶质降解菌株,对分离菌株通过形态特征、16S rRNA基因进行鉴定,对菌株的理化性质进行分析,并对其降解胶质和稠油的性能进行研究。【结果】分离筛选出细菌菌株21株,并从中筛选出性能较好的4株。经鉴定为分别为Q4-油杆菌(Petrobactersp.)、QB9-嗜热脂肪地芽胞杆菌(Geobacillus stearothermophilus)、QB26-地衣芽胞杆菌(Bacillus licheniformis)、QB36-白色地芽胞杆菌(Geobacillus pallidus),其中QB26菌株效果最好,对该菌株的理化性质进行了分析,并对其降解胶质和稠油的性能进行了研究。结果显示,该菌株可在厌氧条件下生长,并能适应地层环境。分离菌株作用稠油后,饱和烃相对含量均有不同程度的上升,芳香烃、胶质、沥青质相对含量降低,能使胶质相对含量降低5.1%,沥青质相对含量降低2.7%。【结论】分离菌株对NB35-2油田稠油中的胶质具有一定的降解作用,在微生物采油和原油污染处理方面具有应用潜力。     

产表面活性剂石油降解菌BS-5的特性研究

目的确定培养条件对产表面活性剂菌株BS-5的生长及降解特性的影响。方法利用紫外分光光度法、表面张力测定法和气相色谱-质谱联用仪(GC-MS),分别以菌体浓度、培养液表面张力及原油降解率为评价指标。结果菌体生长与产表面活性物质的能力及降解能力呈正相关,且确定最优碳源为0.5%的可溶性淀粉,氮源为1.0%的玉米浆,降解时间为6d,在此条件下原油降解率最高达42.3%。结论菌株培养条件的优化提高了菌株自身生长、产表面活性剂及降解原油的能力,为石油污染修复提供理论依据。     

Biodegradation of chlorpyrifos by enterobacter strain B-14 and its use in bioremediation of contaminated soils

Six chlorpyrifos-degrading bacteria were isolated from an Australian soil and compared by biochemical and molecular methods. The isolates were indistinguishable, and one (strain B-14) was selected for further analysis. This strain showed greatest similarity to members of the order Enterobacteriales and was closest to members of the Enterobacter asburiae group. The ability of the strain to mineralize chlorpyrifos was investigated under different culture conditions, and the strain utilized chlorpyrifos as the sole source of carbon and phosphorus. Studies with ring or uniformly labeled [(14)C]chlorpyrifos in liquid culture demonstrated that the isolate hydrolyzed chlorpyrifos to diethylthiophospshate (DETP) and 3, 5, 6-trichloro-2-pyridinol, and utilized DETP for growth and energy. The isolate was found to possess mono- and diphosphatase activities along with a phosphotriesterase activity. Addition of other sources of carbon (glucose and succinate) resulted in slowing down of the initial rate of degradation of chlorpyrifos. The isolate degraded the DETP-containing organophosphates parathion, diazinon, coumaphos, and isazofos when provided as the sole source of carbon and phosphorus, but not fenamiphos, fonofos, ethoprop, and cadusafos, which have different side chains. Studies of the molecular basis of degradation suggested that the degrading ability could be polygenic and chromosome based. Further studies revealed that the strain possessed a novel phosphotriesterase enzyme system, as the gene coding for this enzyme had a different sequence from the widely studied organophosphate-degrading gene (opd). The addition of strain B-14 (10(6) cells g(-1)) to soil with a low indigenous population of chlorpyrifos-degrading bacteria treated with 35 mg of chlorpyrifos kg(-1) resulted in a higher degradation rate than was observed in noninoculated soils. These results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.     

A Novel Olive Oil Degrading Thermoactinomyces Species with a High Extremely Thermostable Lipase Activity

A filamentous, Gram‐positive, spore forming aerobic bacterium was isolated from olive oil contaminated soil (Al Koura, Lebanon) on rhodamine agar plates at 60 °C. The isolate, HRK‐1 produced large quantities of an extracellular thermostable lipase which degrades olive oil. It was primarily classified as a Thermoactinomyces sp. due to the filamentous structure of its cells that bear one spore each on an un‐branched sporophore, the resistance of its spores to boiling, utilisation of sucrose as a carbon source and production of dark pigments. The isolate grew optimally at a temperature of 60 °C, a pH of 7.3 and an orbital shaking of 250 rpm. It showed an efficient olive oil degrading ability. No traces of triolein were detected after a 36‐h cultivation. A concentration of 10 % [v/v] olive oil did not inhibit its growth. Lipase production was constitutive, and did not depend on the presence of olive oil. The optimum concentration of olive oil for lipase activity was 1 % [v/v], and the activity was not enhanced at higher concentrations, but on the contrary, a decrease in enzyme activity was recorded. The lipase of HRK‐1 was preliminarily characterised in the crude cell‐free supernatant with a specific activity of 0.14 U/mg. It has an optimum activity at 60 °C and a pH of 8.0. This lipolytic enzyme showed resistance to boiling and to a wide range of metallic ions and inhibitors. The formation of this heat‐stable lipase started in the early exponential growth phase, while a maximum extracellular enzyme activity was detected at the end of the decline phase, when most of the cells appeared as spherical spores. The exceptionally high activity of lipase (2.37 U/ml) produced by HRK‐1 measured in the cell free supernatant clearly indicated the commercial importance of this isolate, especially after it showed great stability at elevated temperatures.     

Bioaugmentation potential of a vinyl chloride-assimilating Mycobacterium sp., isolated from a chloroethene-contaminated aquifer

An aerobic bacterium, Mycobacterium sp. strain TRW-2 that assimilated vinyl chloride (VC) or ethene (ETH) as the sole carbon source was isolated from a chloroethene-degrading enrichment culture. The strain TRW-2 also degraded cis-dichloroethene (cis-DCE) in mineral salts medium, but only when VC was present as the primary carbon source. However, no degradation of trans-dichloroethene or trichloroethene occurred in either the presence or absence of added VC. The measured growth yield values were 6.53 and 14.1g protein/mol of VC and ETH utilized, respectively. Inoculation by strain TRW-2 in microcosms prepared with aquifer samples resulted in rapid degradation of VC, whereas native bacteria degraded negligible amounts of VC within the same time period, thus suggesting bioaugmentation potential of the isolate. Phylogenetic analysis of the 16S rDNA sequence of the isolate revealed 98% sequence similarity to the members of the genus Mycobacterium. In summary, the isolate's ability to degrade VC, cis-DCE, and ETH and also its ability to survive and degrade VC in the presence of other microorganisms is relevant to the remediation of VC-impacted aquifers.