A/O/O生物流化床处理焦化废水中酚类组成及降解特性分析

为了研究实际焦化废水处理工程中酚类污染物的组成及降解特性,实验中采用HLB小柱固相萃取水样,GC-MS选择性离子扫描方法检测环境中15种酚类污染物,除苯酚的平均回收率为72.6%以外,其他14种酚类的回收率在87.6%~102.3%之间,平行测定标准偏差均小于7.62%,能够满足环境中酚类污染物测定的需要。实验结果表明,焦化废水中含有高浓度的苯酚、甲基酚和萘酚,同时存在微量的氯酚和硝基酚。在生物流化床A/O/O组合工艺处理焦化废水的过程中,厌氧阶段高浓度酚类(苯酚、甲基酚和萘酚)、氯酚类去除率分别为29.3%和31.6%;一级好氧阶段分别为99%和92.4%;二级好氧阶段分别达到89%和6%;最终出水中酚类污染物浓度0.045 mg/L,满足钢铁行业废水达标排放要求。     

吡啶缺氧生物降解特性及其降解产物

吡啶是焦化废水中较为典型的含氮杂环化合物,难以被生物降解。通过研究吡啶的缺氧生物降解特性,并对其降解产物进行鉴定,以期为实际生产提供理论依据和为今后进一步研究做出铺垫。结果表明,吡啶在本实验条件下的最佳降解浓度为80 mg·L-1,对于后期测定降解中间产物,该浓度和其降解周期均较为合适;戊二醛为吡啶在缺氧反硝化降解过程中的一个重要中间产物,其浓度在反应进行32 h时积累达到最大值。在上述实验基础上,在底物中加入40 mg·L-1苯酚,其对吡啶的降解产生抑制作用,戊二醛浓度最大值出现在反应进行40 h处,由此推断苯酚对吡啶降解的抑制作用可能产生于吡啶开环脱氮阶段。     

嗜联苯红球菌B403对酚类污染物的降解特性及动力学分析

为提高降酚菌株的降酚能力,实验测定了嗜联苯红球菌B403对6种酚的最小抑菌浓度,考察了该菌在不同碳源条件下的生长与降酚特性及其关联,进而研究其降解动力学规律。结果表明,菌株B403对苯酚、间甲酚、邻苯二酚、对硝基苯酚、2,4-二氯苯酚和2,4,6-三氯苯酚的最小抑菌浓度分别为1 190、630、700、140、70、48 mg·L~(-1),菌株B403对苯酚、间甲酚、邻苯二酚表现出较强的耐受性。分别以这3种酚为唯一碳源,该菌株能有效降解苯酚和间甲酚,无机盐培养基中处理30h后,苯酚、间甲酚、邻苯二酚的降解率分别为97.85%、100%、56.54%;当有其他有机碳源存在时,菌株B403的生物量大幅度提高,3种酚的降解效率也显著提高,处理15 h后LB-无机盐混合培养基中苯酚、间甲酚、邻苯二酚的降解率分别为98.92%、99.93%、94.35%。菌株B403的降酚动力学过程符合Haldane模型,菌株B403降解苯酚的动力学参数为q_m=0.503 h~(-1),K_s=270.9 mg·L~(-1),K_I=69 mg·L~(-1);降解间甲酚时,q_m=0.672 h~(-1),K_s=171.9 mg·L~(-1),K_I=23.74 mg·L~(-1);降解邻苯二酚时,q_m=1.749 h~(-1),K_s=541.9 mg·L~(-1),K_I=42.61 mg·L~(-1)。根据动力学方程,推论降解苯酚、间甲酚、邻苯二酚的最佳浓度分别为136.4、87.4、116.1 mg·L~(-1)。综合上述结果,其他有机碳源的存在可以显著提高该菌株降酚能力和降解效率,在工业含酚废水治理及有机质丰富的酚类污染土壤修复领域具有一定的应用潜力。     

染料结晶紫降解菌分离及其特性研究

从印染废水中筛选分离得到结晶紫（CV）降解菌株H，并对其脱色条件和机理进行了研究。结果表明，在外加生长基质条件下，菌株H不仅对CV降解脱色而且能降解中间产物。在pH7．0、35℃、摇床转速180r／min条件下，菌株H有最佳的脱色效果。对于20mg／L CV溶液，生长细胞降解0．5h，脱色率可达95％。休眠细胞对CV的降解规律也进行了对比探讨。菌株H对CV脱色过程遵循一级动力学方程，脱色速率常数k随CV浓度升高而降低，生长细胞的k值约为休眠细胞的6～7倍。     

菌源对多环芳烃降解菌的筛选及降解性能的影响

高效降解菌的筛选对利用生物修复技术有效去除环境中的多环芳烃具有重要意义。分别以石油污染土壤和焦化废水活性污泥为菌源,分离出芘降解菌和混合PAHs(菲、荧蒽和芘)降解菌共14株并对其降解性能进行对比研究。结果表明,筛选得到的菌株分别属于9个菌属,其中2种菌源共有的菌属为Mycobacterium sp.、Ralstonia sp.和Shinella sp.。芘和PAHs的高效降解菌(CP16和CM32)均属于分支杆菌属(Mycobacterium),来源于焦化废水活性污泥;菌株CP16对芘(50mg/L)的7 d降解率为74.99%,CM32对PAHs(菲50 mg/L、荧蒽和芘各10 mg/L)的7 d降解率为100%。因此,以焦化废水活性污泥为菌源更有利于获得高效的多环芳烃降解菌。     

白腐菌在固体培养基下对吲哚和吡啶的降解

研究了稻草秆粉介质中白腐菌对吲哚和吡啶的降解.实验结果表明,质量浓度分别为200、80 mg/L左右的吲哚可被白腐菌去除99%以上,质量浓度为74 mg/L吡啶的去除率为61.5%;白腐菌在稻草秆粉培养体系中对吲哚和吡啶的降解,符合零级反应动力学,其中反应速率常数K(高浓度吲哚)＞K(低浓度吲哚)＞K(吡啶);高低浓度吲哚和吡啶3个降解体系的漆酶活力在第6天达到最大;漆酶在吲哚和吡啶降解过程中起着较重要的作用,但酶活的变化与吲哚和吡啶的相对去除率不呈线性相关,稻草秆粉培养基中的介质和培养环境在降解过程中可能也起着重要作用.     

染料结晶紫降解菌分离及其特性研究

从印染废水中筛选分离得到结晶紫(CV)降解菌株H,并对其脱色条件和机理进行了研究.结果表明,在外加生长基质条件下,菌株H不仅对CV降解脱色而且能降解中间产物.在pH 7.0、35℃、摇床转速180 r/min条件下,菌株H有最佳的脱色效果.对于20 mg/L CV溶液,生长细胞降解0.5 h,脱色率可达95%.休眠细胞对CV的降解规律也进行了对比探讨.菌株H对CV脱色过程遵循一级动力学方程,脱色速率常数k随CV浓度升高而降低,生长细胞的k值约为休眠细胞的6～7倍.     

染料降解菌的脱色特性、降解酶系及基因定位研究进展

本文分析了当前染料废水微生物降解优势菌的降解效果及降解机制等,介绍了三种染料降解酶的催化机理和影响因素,阐明了某些降解菌中的质粒可以控制不同结构染料的脱色。最终指出了提高菌株应用价值的两种途径：一是筛选或构建出具有多功能性的超级菌;二是在不改变染料性质的前提下,向其分子结构中引入特定取代基团,以提高其生物降解性。     

金属纳米材料在厌氧条件下对脱氮副球菌反硝化作用的影响

以脱氮副球菌YF1为实验菌株,研究纳米Fe0和纳米Fe/Ni 2种金属纳米材料对菌体生长及其反硝化作用的影响。实验结果表明:添加纳米材料到反应体系中会降低实验菌株的生长量和生物反硝化作用,纳米Fe/Ni对实验菌株的毒性比纳米Fe0大。在含硝态氮初始浓度为100 mg/L的反硝化培养基中接种脱氮副球菌,于30℃培养20 h,脱氮率为89.47%,而菌+1 000 mg/L纳米Fe/Ni的体系脱氮率仅为64.33%;菌+1 000 mg/L纳米Fe0体系的脱氮率为76.36%。不同体系的反硝化过程均可采用零级动力学模型进行拟合(相关系数R2>0.92)。这2种金属纳米材料对实验菌株的生长量及其反硝化作用的影响程度,与体系的pH和温度有较大关系。     

Biodegradation of insecticide carbofuran by Paracoccus sp. YM3

A bacterium (Paracoccus sp. YM3) capable of degrading carbofuran was isolated from carbofuran-contaminated sludge. The strain was shown to metabolize carbofuran (50 mg L(-1)) to carbofuran-7-phenol in minimal salt medium within 6 days in which the pesticide was the only source of carbon. Carbofuran and its main metabolite were analyzed by high performance liquid chromatography (HPLC). The addition of an other carbon source led to accelerated biodegradation. The relevant degrading-enzyme was intracellular and inducible. A tobacco hypersensitivity experiment showed that YM3 could eliminate carbofuran in soils effectively and safely. This is the first report of a Paracoccus sp. that could degrade carbofuran. The present study may provide a basis for biotreatment of wastewaters and bioremediation of carbofuran-contaminated soils.     

Biodegradation of insecticide carbofuran by Paracoccus sp. YM3

A bacterium (Paracoccus sp. YM3) capable of degrading carbofuran was isolated from carbofuran-contaminated sludge. The strain was shown to metabolize carbofuran (50 mg L^?1) to carbofuran-7-phenol in minimal salt medium within 6 days in which the pesticide was the only source of carbon. Carbofuran and its main metabolite were analyzed by high performance liquid chromatography (HPLC). The addition of an other carbon source led to accelerated biodegradation. The relevant degrading-enzyme was intracellular and inducible. A tobacco hypersensitivity experiment showed that YM3 could eliminate carbofuran in soils effectively and safely. This is the first report of a Paracoccus sp. that could degrade carbofuran. The present study may provide a basis for biotreatment of wastewaters and bioremediation of carbofuran-contaminated soils.     

一株荧蒽降解菌的筛选鉴定及降解特性

采用富集培养方法,从多环芳烃污染的土壤中分离筛选到一株能以高分子量的多环芳烃荧蒽为惟一碳源和能源且生长状况良好的菌株DN002。通过形态观察、生理生化指标及16S rRNA同源序列分析比对,结果表明,该菌株为木糖氧化产碱菌(Achromobacter xylosoxidans),最适生长温度为32℃,最适生长pH为7～7.5。该菌株对荧蒽有较强的降解能力,在14 d内对500 mg/L的荧蒽的降解率为92.8%。菌株细胞蛋白SDS-PAGE结果显示,经荧蒽诱导后,在分子量为18～66 kDa范围内有显著的差异蛋白条带。     

Isolation, characterization and diuron transformation capacities of a bacterial strain Arthrobacter sp. N2

A bacterial strain able to transform diuron was isolated from a soil by enrichment procedures. Strain isolation was realized by plating on minimal-agarose medium spread with this herbicide and selecting the colonies surrounded by a clear thin halo. One strain was characterized and identified as an Arthrobacter sp. It metabolized diuron and the final transformation product, 3,4-dichloroaniline, was produced in stoichiometric amounts. The transformation of diuron at different concentrations was more efficient in the presence of alternative sources of carbon and nitrogen. The bacterial activity was also evaluated in soil microcosms with a consequent disappearance of diuron and concomitant appearance of 3,4-dichloroaniline, of which the concentration decreased thereafter. Bacterial cells inoculated in the microcosms survived as viable but eventually nonculturable cells.     

1,1-二氯乙烯降解菌的分离鉴定及降解特性

从好氧活性污泥中分离得到一株能以1,1-二氯乙烯(1,1-DCE)作为惟一碳源和能源生长的革兰氏阴性菌株D-B,经鉴定属于产碱杆菌属(Alcaligenessp.)。当维持菌株D-B浓度一定时,1,1-DCE的去除率随着1,1-DCE浓度的增大先增加后降低,且降解过程主要发生在加入1,1-DCE后的3~5 h内。当1,1-DCE的初始浓度为300μg/L时去除率达到最大值85.32%。菌株D-B对1,1-DCE的降解符合Monod方程,饱和常数Ks=21.96 mg/L,1,1-DCE的最大比基质降解速率Vmax=50.76 mg/(L.h)。     

Degradation characteristics of a dibenzofuran-degrader Terrabacter sp. strain DBF63 toward chlorinated dioxins in soil

Nonylphenols (NPs) are the primary stable metabolites of alkylphenol polyethoxylates (APEs), a family of compounds widely used in industry and in some domestic products. As NPs accumulate in sediments in aquatic environments, the risk to benthic organisms needs to be assessed. In this study 4NP-spiked sediments were tested on larvae of the dipteran Chironomus riparius. First instar larvae obtained from populations at three different sources were used. To spike the sediments, an equilibration procedure between water and sediment was adopted to avoid the use of solvents. Lower 10-d LC50 values were determined for two populations of C. riparius from clean environments (315-465 and 315-350 microg g(-1) d.w., respectively) than those of a strain deriving from a population collected in a polluted river (600-680 microg g(-1) d.w.). Larval growth always decreased with increasing 4NP concentration but without any defined trend. The results of this study suggest that tolerance to the toxicant can be developed in populations of polluted environments and that testing procedures should be standardised.     

丛毛单胞菌对邻甲酚及对甲酚的降解特性

考察不同底物浓度、pH及金属离子对丛毛单胞菌(Comamonas sp.)Z1(以下简写为Z1)降解邻甲酚与对甲酚的影响,并利用高效液相色谱/质谱对降解产物进行分析。结果表明:(1)Z1可利用邻甲酚与对甲酚作为唯一碳源进行生长,36h内能将25～75mg/L邻甲酚、25～200mg/L对甲酚完全降解。(2)Z1可在pH为8.0时将50mg/L邻甲酚或100mg/L对甲酚快速降解。(3)Mg~(2+)对Z1生长、底物降解产生促进作用,Co~(2+)、Ni~(2+)、Cu~(2+)等金属离子则具有抑制作用。(4)推断Z1能利用龙胆酸与儿茶酚途径降解邻甲酚,通过龙胆酸途径降解对甲酚。     

洚解菌Pigmentiphagasp．strainD-2对啶虫脒污染土壤的生物修复作用

啶虫脒属于一种新型的氯化烟碱类杀虫剂,被认为是替代有机磷农药的重要品种之一,在世界范围内已经得到了广泛的应用,其在环境中的残留备受关注,利用微生物修复异源污染物是一种有效的措施。在实验室条件下,研究了高效降解菌D-2（噬染料菌属,Pigmentiphagasp．）对被啶虫脒污染土壤的修复作用及其影响因素。结果表明,降解菌株在未灭菌土壤中的降解效果要略好于灭菌土壤,在土壤外源添加降解菌2×10^8cfu／g,温度20～40℃,弱碱性（pH7．5）的条件下,该菌株能有效降解土壤中1～200mg／kg的啶虫脒。啶虫脒施用对土壤种群结构有一定的影响,可以刺激细菌和真菌的生长,从而使土壤微生物群落结构发生改变,而降解菌的施用可缓解啶虫脒对土壤微生物的影响,修复受污染土壤。因此,人工接种降解菌D-2可提高土壤中啶虫脒的降解率,有效降低其在土壤中的残留。