不同微生物制剂对土壤中结合态Zn稳定性的影响

为了探索修复Zn污染土壤的有效途径,在4种含Zn量分别为97.4、300、600、900mg/kg的土壤中分别添加木霉菌(40g/kg)和AB菌(40mL/kg)后种植苋菜。测定结果显示,添加木霉的4种土壤中有效态Zn含量比对照分别减少了1.75%、13.9%、19.47%、14.86%,苋菜中Zn的富集量比对照分别提高了56.4%、37.4%、25.23%和47.06%;添加AB菌的4种土壤中有效态Zn含量比对照分别提高了15.79%、31.02%、26.55%和17.75%,苋菜中Zn的富集量比对照分别提高了47.73%、33.8%、29.99%、41.17%。这些结果表明AB菌和木霉菌对土壤中有效态Zn含量的影响存在差异,不同微生物菌剂对土壤重金属有效态的影响不同,选择合适的微生物菌剂,对重金属污染土壤的微生物修复具有重要意义。     

生物修复对石油污染土壤微生物活性的影响

以陕北地区石油污染土壤为研究对象,利用微生物修复法对油污土壤进行了修复处理,对修复过程中不同组分烃浓度的变化、土壤四种酶活(多酚氧化酶、过氧化氢酶、脱氢酶、脂肪酶)、微生物对不同组分烃的代谢活性等生物因素进行了测定,并利用SPSS软件对不同组分烃的浓度变化及土壤生物性因素进行相关性分析。研究结果表明,微生物修复技术可有效去除土壤中不同组分烃,修复进行11周,土壤中烷烃、多环芳烃去除率分别为46.8%和39.9%。修复处理可提高土壤过氧化氢酶、脂肪酶活性,以及土壤微生物对烷烃、多环芳烃的代谢能力,土壤多酚氧化酶和脱氢酶活性呈先升后降的趋势。相关性分析结果表明,烷烃的降解与微生物对烷烃的代谢活性、土壤脱氢酶和过氧化氢酶活性相关,多环芳烃的生物降解与脱氢酶和过氧化氢酶活性相关;微生物修复作用可提高土壤中不同组分烃与微生物活性之间的相关关系。     

Bioconversion of dieldrin by wood‐rotting fungi and metabolite detection

BACKGROUND: Dieldrin is one of the most persistent organochlorine pesticides, listed as one of the 12 persistent organic pollutants in the Stockholm Convention. Although microbial degradation is an effective way to remediate environmental pollutants, reports on aerobic microbial degradation of dieldrin are limited. Wood‐rotting fungi can degrade a wide spectrum of recalcitrant organopollutants, and an attempt has been made to select wood‐rotting fungi that can degrade dieldrin, and to identify the metabolite. RESULTS: Thirty‐four isolates of wood‐rotting fungi were investigated for their ability to degrade dieldrin. Strain YK543 degraded 39.1 ± 8.8% of dieldrin during 30 days of incubation. Phylogenetic analysis demonstrated that strain YK543 was closely related to the fungus Phlebia brevispora Nakasone TMIC33929, which has been reported as a fungus that can degrade chlorinated dioxins and polychlorinated biphenyls. 9‐Hydroxydieldrin was detected as a metabolite in the cultures of strain YK543. CONCLUSION: It is important to select the microorganisms that degrade organic pollutants, and to identify the metabolic pathway for the development of bioremediation methods. Strain YK543 was selected as a fungus capable of degrading dieldrin. The metabolic pathway includes 9‐hydroxylation reported in rat's metabolism catalysed by liver microsomal monooxygenase. This is the first report of transformation of dieldrin to 9‐hydroxydieldrin by a microorganism. Copyright © 2010 Society of Chemical Industry     

转基因表达有机磷水解酶(OPH)提高黄瓜降解蝇毒磷能力的初步研究

为快速提高黄瓜降解有机磷农药残留的能力,选取能广泛降解有机磷农药的有机磷水解酶(OPH)为表达蛋白,构建CaMV 35S启动子驱动有机磷水解酶基因(opd)的植物表达载体pSOP,经双酶切证明重组载体含有插入位置和方向皆正确的目的片段。通过农杆菌介导遗传转化黄瓜子叶节,诱导和筛选出9株抗性苗,获得3株GUS染色和PCR阳性转化苗。酶活性分析表明,转基因黄瓜降解蝇毒磷能力是对照(非转基因株)的4.7~9.7倍,最高达到7.8μmol/(mg.min),有助于加快降解黄瓜中的有机磷农药残留,为食品安全研究提供借鉴。     

阳离子对耐辐射奇球菌对放射性铯生物吸收的影响

耐辐射奇球菌能够耐受高剂量的辐射,促使人们考虑利用此特性进行放射性核素和有毒化学品的生物修复。但是,有关耐辐射奇球菌对放射性铯的生物吸收却未见报道。本文研究了耐辐射奇球菌对放射性铯的生物吸收及其他阳离子对其生物吸收的影响。在平衡状态时,耐辐射奇球菌对放射性铯的最大吸收量为2100kBq/kg(鲜重)。在供试的一价阳离子中,NH4+对其生物吸收的拮抗作用最强,但是只有当NH4+的浓度超过100mmol/L时,这种拮抗作用才比较明显。二价阳离子,如Ca2+和Pb2+也能降低耐辐射奇球菌对放射性铯的吸收。Al3+和Cr3+对耐辐射奇球菌具有较强的细胞毒性,当其浓度超过1mmol/L时,耐辐射奇球菌的生长就完全被抑制。     

Influence of environmental factors on the biological treatment of organic compounds in contaminated lagoon sediments

Background and Scope  Many technologies available to remediate soils are not cost-effective when applied to marine and lagoon sediments, due to the physico-chemical characteristics of these matrices (high percentages of small particle size material, high moisture and organic matter content, many different types of inorganic and organic contamination). For these types of waste, slurry phase bioreactors can provide versatile processes, with very high removal efficiencies of recalcitrant organic compounds. The biodegradation of these contaminants strictly depends on the specific structure of the molecules and on environmental factors, such as the dissolved oxygen concentration, salinity, pH, and macronutrient availability. This paper presents the results of lab-scale tests performed to investigate the effect of the above-mentioned factors on the removal efficiency of saturated hydrocarbons, polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs) in slurry phase biological treatment of lagoon sediments. Methods  Sediments were contaminated by saturated hydrocarbons (958 mg/kg d.w.), polyaromatic hydrocarbons (PAHs) (29 mg/kg d.w.) and polychlorobiphenyls (PCBs) (236 μg/kg d.w.). Carbon to nitrogen to phosphorous ratios in the matrix were not properly balanced for biological treatment. High concentrations of metals were also present (Cu: 200 mg/kg d.w.; Zn: 1710 mg/kg d.w.; As: 33 mg/kg d.w.; Cd: 13 mg/kg d.w.; Pb: 244 mg/kg d.w.). Biodegradation studies were carried out at 21 ± 1°C, in completely mixed slurry phase aerobic, anaerobic and sequential anaerobic/aerobic batch systems (3.5 1), with a solid to liquid ratio of 10% w/w. Where required, anaerobic conditions occurred naturally within three days of not aerated treatment. The aerated reactors were also equipped with traps for the waste vapors. Twelve tests were performed, over a period between ten and twenty-two days, mixing water, sediments and different amounts of various additives (macronutrients to balance C:N:P to 100:10:1 w/w, sodium chloride from 0 to 20 g/1, pH buffer solution) in the reactors, depending on the test being performed. Results and Discussion  No significant differences among the removal efficiencies of saturated hydrocarbons in tests could be observed. Abatements between 63% and 93% were obtained. The dissolved oxygen concentration was the most critical factor affecting the treatment of PAHs. Removal efficiencies below 20% were obtained for two and three-ring PAHs in the non-aerated tests. Higher values, between 45% and 61%, were obtained for these compounds in the aerated treatments; however, large (16% to 21%) abiotic losses (volatilization) were observed in these cases. Four-ring PAH removal efficiency was below 5% in all the non-aerated treatments, except for test performed without additions (30%); in the aerobic processes, removal efficiencies between 40% and 50% were obtained, except for test performed with nutrient addition and 10 g NaCl/1 (16%). Abatements of five and six-ring PAHs were between 43% and 69% in the aerated tests, and between 17% and 51% in the non-aerated treatments. Concerning PCBs, tests evidenced that reductive dehalogenation mechanisms have occurred in the anaerobic reactors with the most stable pH values, resulting in an increase of 2,4,4′-CB and 2,2′,5,5′-CB concentrations; the aerobic treatments did not modify the PCB mixture. In both types of systems, no variation of the total PCB concentration could be observed. Conclusions  This study showed that saturated hydrocarbon removal efficiency was nearly insensitive to the environmental factors investigated. The molecule structure and the dissolved oxygen concentration were the most affecting factors the removal efficiency of PAHs. PCB degradation under anaerobic conditions could be related to the pH values measured during the tests. Evaluation of results suggested that the abatement of pollutants investigated was not limited by a high salinity. High concentrations of dissolved metals and macronutrient addition did not influence the removal efficiency. Recommendations and Outlook. The slurry phase biological treatment of contaminated sediments could be applied whenever moderate removal efficiencies were required for remediation from saturated hydrocarbons and PAHs within a few days; further studies should be performed to improve the PCB abatement. Aerobic conditions should be maintained for the biodegradation of polyaromatic compounds; seawater or lagoon water could be used in the system.     

菲降解菌的分离鉴定及其在污染土壤生物修复中的应用

采用室内培养方法,从吴江市郊长期被多环芳烃污染的土壤中富集到以菲为唯一碳源和能源的菲降解复合微生物菌群,复合菌群在7d内对无机盐液体中菲（含量100mg·L^-1）的降解率达到99%。从复合菌群中分离纯化获得两株菲高效降解菌B1和L2,经过菌体形态特征、生理生化特征和16SrDNA序列分析,鉴定菌株B1为百日咳博行特氏菌（Bordetella petrii）,菌株L2为墨西哥假黄单胞菌（Pseudoxanthomonas mexicana）。这两株菌在菲含量为100mg·L^-1的无机盐培养液中,7d内对菲（含量100mg·L^-1）的降解率大约为80%,9d内的降解率可达到99%。将复合菌群和菲污染土壤混合,在光照培养箱中进行培养修复。结果表明,修复88d后,接种复合菌群的低污染浓度（8.22mg·kg^-1）处理和高污染浓度（39.65mg·kg^-1）处理的菲去除率分别达到95.74%和98.06%。     

土著原油降解真菌的筛选及其降解效果

[目的]筛选土著原油降解真菌,研究其与植物联合修复原油污染的效果。[方法]从大庆长期原油污染的土壤中分离出原油降解真菌,通过菌落、菌丝形态及rDNA-ITS序列比对,确定种属,并且研究目标菌株在液体培养条件下单独接种于油污土壤和与玉米混合接种对土壤中总石油烃的降解效果。[结果]分离出的4种真菌分别为以木霉菌、尖孢镰刀菌、禾生小从壳和玉米赤霉,分别命名为x3、x5、x7和x9,4种真菌在3种接种条件下均表现出高效的石油烃降解率。但是,4种菌株在液体培养条件下降解率高于土壤中的,其中x9号真菌在与玉米混合接种后达到最大降解率78.01%,并在玉米根系发现明显的根瘤。[结论]真菌与植物联合修复土壤污染物是一种长期有效的、有利于土壤生境恢复的治理方法之一。     

茚虫威降解菌海藻酸钠微球制剂研制及应用效果

[目的]以海藻酸钠为载体制备降解菌斯氏假单胞菌(Pseudomonas stutzeri)ACCC 02521菌株微球制剂,确定该制剂降解农田土壤茚虫威的应用条件.[方法]通过微滴包埋成球法,将湿菌体重悬后加入海藻酸钠溶液,混匀后逐滴滴至CaCl2溶液造粒,低温固定后,以0.9％NaCl溶液洗涤,测定降解菌微球的传质性...     

城市生活污水人工土-蚯蚓快滤复合处理床研究

不同砂土比瓷盆试验结果表明，当砂土比为9：9时适宜于蚯蚓生存。采用此种砂土比配制成人工土壤填充模拟土柱进行了为期6个月的试验，研究了蚯蚓对污水的净水效果及有机质的降解情况。结果表明，加入蚯蚓的土校比对照具有更好的处理效果，它不但可提高COD、BOD5、NH4^ 、-N、TN和TP的去除率，分别为2％—4％、2％—5％、8％-14％、3％—13％和3％-6％，而且还可以减轻人工土柱中有机质的积累和堵塞问题。