运用双液相系统进行三氯苯的生物降解

Due to easy volatilization of volatile organic compounds from water,it is difficult to monitor their aerobic biodegradation in the traditional single water system.Whether a two-liquid-phase system(TLPS) could overcome this obstacle and enhance the degradation of volatile contaminants? In this study,a TLPS composed of silicone oil and water was employed to investigate the biodegradation of volatile compounds,trichlorobenzenes(TCBs),by the adapted microorganisms in an activated soil.The degradation and volatilization of TCBs in TLPS and in a single water system were compared.The results showed that due to volatilization losses of TCBs,the mass balance of TCBs in a single water system was very low.In contrast,using TLPS could effectively inhibit the volatilization losses of TCBs and achieved a very good mass balance during the biodegradation process.Meanwhile,the TLPS could increase microbial activity and microbial growth during the degradation process.With TLPS,the TCB degradation was in descending order of 1,2,4-TCB> 1,2,3-TCB>> 1,3,5-TCB,which was related to the exposed concentration of the contaminants in soil.This study showed that TLPS could be employed as an effective tool to evaluate the biodegradation of volatile hydrophobic organic compounds,which could not be achieved with the traditional single water system.     

Influence of kaolinite and montmorillonite on benzo[a]pyrene biodegradation by Paracoccus aminovorans HPD-2 and the underlying interface interaction mechanisms

Clay minerals play an important role in biogeochemical cycling.Here,kaolinite and montmorillonite,the two most abundant and widespread clay minerals with typical layered structures,were selected to investigate and compare their effects on the biodegradation of benzo[a]pyrene(BaP)by Paracoccus aminovorans HPD-2 and to investigate the underlying interface mechanisms.Overall,the BaP degradation efficiency was significantly higher 7 d after montmorillonite addition,reaching 68.9%(P<0.05),when compared with that of the control without addition of clay minerals(CK,61.4%);however,the addition of kaolinite significantly reduced the BaP degradation efficiency to 45.8%.This suggests that kaolinite inhibits BaP degradation by inhibiting the growth of strain HPD-2,or its strong hydrophobicity and readily agglomerates in the degradation system,resulting in a decrease in the bio-accessibility of BaP to strain HPD-2.Montmorillonite may buffer some unfavorable factors,and cells may be fixed on the surface of montmorillonite colloidal particles across energy barriers.Furthermore,the adsorption of BaP on montmorillonite may be weakened after swelling,reducing the effect on the bio-accessibility of BaP,thus promoting the biodegradation of BaP by strain HPD-2.The experimental results indicate that differential bacterial growth,BaP bio-accessibility,interface interaction,and the buffering effect may explain the differential effects of the different minerals on polycyclic aromatic hydrocarbon biodegradation.These observations improve our understanding of the mechanisms by which clay minerals,organic pollutants,and degrading bacteria interact during the biodegradation process and provide a theoretical basis for increasing the biodegradation of soil pollutants by native microorganisms under field conditions.     

二氯喹啉酸·苄嘧磺隆复合污染降解菌的特性研究

A bacterial strain, designated as LS, was isolated from a contaminated soil and was found to be capable of utilizing quinclorac, bensulfuronmethyl, and a mixture of the two as carbon and energy sources for growth. Strain LS was identified as Ochrobactrum sp. based on its physiological-biochemical properties, 16S rDNA sequences, and phylogenetic analysis. The extent of degradation of quinclorac and bensulfuronmethyl at initial concentrations of 1.5 and 0.1 g L^-1 was 90% and 67%, respectively, as measured by high performance liquid chromatography （HPLC）. When a herbicide mixture of 0.34 g L^-1 quinclorac and 0.02 g L^-1 bensulfuronmethyl was applied as carbon sources, quinclorac and bensulfuronmethyl were degraded at 95.7% and 67.5%, respectively. It appears that quinclorac is utilized more easily in a mixture than in a single state. The optimal temperature for growth of strain LS was 37 ℃. Strain LS grew well at pH 6 to 9 and had the highest degradation level for quinclorac and bensulfuronmethyl at an initial pH of 7 and 8, respectively. Addition of 0.25 g L^-1 yeast extract could promote the growth and extent of degradation of quinclorac and bensulfuronmethyl by strain LS. Strain LS also showed the capability to degrade other aromatic compounds such as catechol, propisochlor, 4-chloro-2-methylphenoxyacetic acid sodium （MCPA-Na） and imazethapy. The isolate LS shows a huge potential to be used in bioremediation for treating complex herbicide residues.     

Isolation and Characterization of a Bensulfuron-Methyl-Degrading Strain L1 of Bacillus

The objectives of this study were to isolate a bensulfuron-methyl (BSM)-degrading strain of Bacillus spp. and to eval-uate its effectiveness in remediation of a BSM-contaminated soil. A BSM-degrading bacterium, strain L1, was successfully isolated in this study. Strain L1 was identified as Bacillus megaterium based on its morphological, physiological, and biochemical properties, G+C content, phylogenetic similarity of 16S rDNA, and fatty acid composition. Two experiments were used to examine BSM degradation by strain L1. When BSM was used as a sole carbon source in a mineral salt medium, the average degradation rate of BSM by strain L1 was 12.8%, which suggested that the strain was able to utilize BSM as a sole carbon and energy source. Supplement of yeast extract (200 mg L-1 ) significantly (P ≤ 0.01) accelerated the degradation of BSM by strain L1. Almost complete degradation (97.7%) of BSM could be achieved in 84 h with addition of yeast extract. In addition, in a sterile soil with 50 mg L-1 BSM, BSM degradation rate by strain L1 was 94.3% in 42 d, indicating the potential of using microbes for the remediation of BSM-contaminated soils in fields.     

我国几种土壤中铁锰结核的元素组成和地球化学特点

The objective of this research was to isolate a dichlorvos （2,2-dichlorovinyl dimethyl phosphate）-degrading strain of Ochrobactrum sp., and determine its effectiveness in remediation of a dichlorvos-contaminated soil. A dichlorvos-degrading bacterium （strain DDV-1） was successfully isolated and identified as an Ochrobactrum sp. based on its 16S rDNA sequence analysis. Strain DDV-1 was able to utilize dichlorvos as a sole carbon source, and the optimal pH and temperature for its cell growth and degradation were 7.0 and 30 ℃, respectively. Also, the growth and degradation of strain DDV-1 showed the same response to dissolved oxygen. In addition, the soil degradation test indicated that in soil spiked with 100 mg L^-1 or 500 mg L^-1 dichlorvos and inoculated with 0.5% or 1.0% （v/v） strain DDV-1, complete degradation of dichlorvos could be achieved in 24 h. The present study showed that strain DDV-1 was a fast dichlorvos-degrading bacterium in soil. However, further research will be needed to clarify the degradation pathway and the properties of the key enzymes involved in its biodegradation.     

Acinetobacter sp. LMB-5对邻苯二甲脂的降解及对其中酯酶性质的研究

Phthalate esters(PAEs) are extensively applied in industry, and they migrate to environment during the process of production,employ, and treatment and are difficult to be degraded in nature. However, some microorganisms could use them as the carbon source to growth. In this study, an Acinetobacter sp. strain LMB-5, capable of utilizing PAEs, was isolated from a vegetable greenhouse soil.The degradation capability of strain LMB-5 was also investigated by incubation in mineral salt medium containing different PAEs,dimethyl phthalate(DMP), diethyl phthalate(DEP), di-n-butyl phthalate(DBP), and di-(2-ethylhexyl) phthalate(DEHP). The strain could grow well with DMP, DEP, DBP, and DEHP. When the concentration of DBP increased from 100 to 400 mg L~(-1), the half-life extended from 9.5 to 15.5 h. In the concentration range of DBP, the degradation ability of strain LMB-5 could be described by first-order kinetics. During the biodegradation of DBP, three intermediates, 1,2-benzenedicarboxylic acid,butyl methyl ester, DMP,and phthalic acid(PA) were detected, and the proposed pathway of DBP was identified. By analysis of bioinformatics, one esterase was cloned from the genome of LMB-5 and expressed in Escherichia coli. It displayed an ability to break the ester bonds of DBP. The enzyme exhibited maximal activity at pH 7.0 and 40℃ with DBP as the substrate. It was activated by Cu~(2+) and Fe~(3+) and had a high activity in the presence of low concentrations of methanol or dimethylsulfoxide(each 10%, volume:volume). The Acinetobacter sp. strain LMB-5 may make a contribution to the remediation of soils polluted by PAEs in the future.     

一株芽孢杆菌属的苄嘧磺隆降解菌的分离鉴定和降解研究

The objectives of this study were to isolate a bensulfuron-methyl (BSM)-degrading strain of Bacillus spp. and to evaluate its effectiveness in remediation of a BSM-contaminated soil. A BSM-degrading bacterium, strain L1, was successfully isolated in this study. Strain L1 was identified as Bacillus megaterium based on its morphological, physiological, and biochemical properties, G+C content, phylogenetic similarity of 16S rDNA, and fatty acid compositions. Two experiments were used to examine BSM degradation by strain L1. When BSM was used as a sole carbon source in a mineral salt medium, the average degradation rate of BSM by strain L1 was 12.8%, which suggested that the strain was able to utilize BSM as a sole carbon and energy source. In addition, supplement of yeast extract (200 mg L-1) significantly (P ≤ 0.01) accelerated the degradation of BSM by strain L1. Almost complete degradation (97.7%) of BSM could be achieved in 84 h with addition of yeast extract. In addition, when a sterile soil was supplemented with BSM (50 mg L-l), BSM degradation rate was 94.3% in 42 d, indicating the potential of using microbes for the remediation of BSM-contaminated soils in fields.     

Reclamation of oil-induced soil hydrophobicity in the hyper-arid Evrona Nature Reserve, southern Israel

Two oil spills occurred in the Evrona Nature Reserve (southern Israel), in 1975 and 2014. This oil contamination induced highly persistent soil hydrophobicity. The objective of this study was to investigate the decrease in oil-induced soil hydrophobicity under different environmental conditions and to assess the relationship between the hydrophobicity and hydrocarbon content. A laboratory incubation experiment was conducted over 1.5 years to monitor the soil hydrophobicity and total hydrocarbon concentration under different environmental conditions. We hypothesized that the addition of water (20% or 50% saturation), nutrients, and biosurfactants can accelerate the reduction in hydrophobicity and decomposition of hydrocarbons. Water drop penetration time and molarity of ethanol droplet tests were used to assess soil hydrophobicity. In parallel, alkane composition and total petroleum hydrocarbons were evaluated to indicate oil attenuation. The addition of water, nutrients, and biosurfactants resulted in a concomitant reduction in hydrophobicity and hydrocarbon concentration of varying degrees, exhibiting enhanced degradation and hydrophobicity reduction observed in treatments to which nutrients and biosurfactants were added. At the end of the incubation, however, soil hydrophobicity in all treatments remained severe, even though total petroleum hydrocarbon removal was fairly high and reached 40%–80% in the treatments to which water with or without nutrients and/or surfactants was added.     

白腐菌Pleurotus pulmonarius F043降解和转化荧蒽的潜力研究

Fluoranthene, a four-ring polycyclic aromatic hydrocarbon that is possible genotoxic in nature, has been used as an indicator for assessing polycyclic aromatic hydrocarbon(PAH)-containing pollutants. Microbial degradation is one of the promising methods in removing up PAH-contaminated environments. White-rot fungi have showed the ability to degrade a wide range of PAHs. This study aimed to investigate enzyme production, fungal biomass, and glucose utilization during the biodegradation process of fluoranthene by a white-rot fungus Pleurotus pulmonarius F043 and to identify the metabolites produced in the degradation process. The extracellular ligninolytic enzyme system of the fungi, producing laccases and peroxidases, was directly linked to the biodegradation of fluoranthene.The production of ligninolytic enzymes during fluoranthene degradation was related to an increase in the biomass of Pleurotus pulmonarius F043. Fluoranthene removal decreased with an increase in fluoranthene concentrations. The highest biomass production of Pleurotus pulmonarius F043(≥ 4 400 mg L~(-1)) was found in the 10 mg L~(-1) fluoranthene culture after 30 d of incubation. Two fluoranthene metabolites, naphthalene-1,8-dicarboxylic acid and phthalic acid, were found in the process of fluoranthene degradation.Laccase was revealed as the major enzyme that played an important role in degradation process. Suitable conditions must be found to promote a successful fungal biotransformation augmentation in liquid culture.     

从土壤中分离获得的五氯硝基苯降解菌株降解五氯硝基苯特性研究

A bacterial strain,pcnb-21,capable of degrading pentachloronitrobenzene(PCNB) under aerobic and anoxic conditions,was isolated from a long-term PCNB-polluted soil by an enrichment culture technique and identified as Labrys portucalensis based upon its morphological,physiological and biochemical properties,as well as 16S rRNA gene sequence analysis.Effects of different factors,such as temperature and pH,on PCNB biodegradation were studied.Strain pcnb-21 efficiently degraded PCNB at temperatures from 20 to 30 ℃ and initial pH values from 4 to 7,which might be the first time that a Labrys strain was found capable of efficiently degrading PCNB.The degradation of PCNB was affected by oxygen,and the degradation decreased with increasing aeration.Exogenous electron donors such as glucose,lactic acid and succinic acid promoted the biodegradation of PCNB,while electron acceptors such as sodium nitrite,sodium sulfate,sodium nitrate and sodium sulfate inhibited PCNB biodegradation.The degradation of PCNB in sterile and non-sterile soils by a green fluorescent protein(GFP)-labeled strain,pcnb-21-gfp,was also studied.Cells of pcnb-21-gfp efficiently degraded 100 mg kg -1 PCNB in sterile and non-sterile soils and could not be detected after 42 days.Strain pcnb-21 might be useful in bioremediating PCNB-polluted soils and environment.     

铜-苯并[a]芘复合污染体系中铜的微生物吸附特性

研究了铜-苯并[a]芘（BaP）复合污染体系中,嗜麦芽窄食单胞菌对铜的微生物吸附特性。实验结果表明,该菌可以选择性地吸附Cu^2＋,并把NO3^-还原为NO2^-,pH、投菌量、处理时间和铜浓度等因素及BaP均会对铜的生物吸附产生显著的影响,BaP和这4个因素的相互作用对铜的生物吸附也达到了显著的水平。投菌量会对铜吸附过程中F-、Cl^-、NO2^-、NO3^-、PO34^-和SO24-等离子的释放产生显著的影响,BaP则会显著的影响F^-、NO2^-、NO3^-和PO34^-的浓度水平。当BaP的浓度为0、0.1、1.0、10.0 mg.L^-1时,2.5 g.L^-1菌体对pH为6.0、浓度为2 mg.L^-1的铜溶液的吸附率分别高达97.1%、93.8%、94.0%和93.3%。BaP和铜在2 h内均没有造成菌体表面形态的明显变化;处理10 mg.L^-1 Cu^2＋及其与BaP的复合污染2 d后,菌体表面会产生突起结构。     

Influences of kaolinite and montmorillonite on benzo[a]pyrene biodegradation by Paracoccus aminovorans HPD-2 and the underlying interface interaction mechanisms

Clay minerals play an important role in biogeochemical cycling. Here, kaolinite and montmorillonite, the two most abundant and widespread clay minerals with typical layered structures, were selected to investigate and compare their effects on the biodegradation of benzo[a]pyrene (BaP) by Paracoccus aminovorans HPD-2 and to investigate the underlying interface mechanisms. Overall, the BaP degradation efficiency was significantly higher 7 d after montmorillonite addition, reaching 68.9% (P < 0.05), when compared with that of the control without addition of clay minerals (CK, 61.4%); however, the addition of kaolinite significantly reduced the BaP degradation efficiency to 45.8%. This suggests that kaolinite inhibits BaP degradation by inhibiting the growth of strain HPD-2, or its strong hydrophobicity and readily agglomerates in the degradation system, resulting in a decrease in the bio-accessibility of BaP to strain HPD-2. Montmorillonite may buffer some unfavorable factors, and cells may be fixed on the surface of montmorillonite colloidal particles across energy barriers. Furthermore, the adsorption of BaP on montmorillonite may be weakened after swelling, reducing the effect on the bio-accessibility of BaP, thus promoting the biodegradation of BaP by strain HPD-2. The experimental results indicate that differential bacterial growth, BaP bio-accessibility, interface interaction, and the buffering effect may explain the differential effects of the different minerals on polycyclic aromatic hydrocarbon biodegradation. These observations improve our understanding of the mechanisms by which clay minerals, organic pollutants, and degrading bacteria interact during the biodegradation process and provide a theoretical basis for increasing the biodegradation of soil pollutants by native microorganisms under field conditions.     

人工湿地高效好氧反硝化菌的分离鉴定及反硝化特性研究

从增氧型复合垂直流人工湿地中采集样品,利用间歇曝气法富集好氧反硝化菌,并进行分离纯化,共得到10株好氧反硝化菌。其中编号为B13的菌株在初始硝态氮含量为277.23mg·L-1、碳氮比为5的条件下,24h的硝态氮去除率达92.80%,亚硝态氮积累只有12.57mg·L-1,脱氮速率达到20.58mg·L-·1h-1。16S rDNA序列分析表明,该菌与Pseudomonas stutzeri同源性达100%。选用四因素三水平L（934）正交试验表设计实验,通过测定对硝态氮去除能力和亚硝态氮的积累量,研究碳源、碳氮比（C/N）、pH以及溶解氧含量（DO）4种不同因素对B13号菌株好氧反硝化性能的影响。结果表明,该菌株对硝态氮的去除率最大可达99.88%,几乎没有亚硝态氮积累。对硝态氮去除率影响最大的因素为碳氮比,其次为pH,溶解氧含量和碳源。对应的最优条件是碳源为葡萄糖,碳氮比为10,pH为9,溶解氧含量为1.84～3.57mg·L-1。     

苯并[a]芘污染土壤的丛枝菌根真菌强化植物修复作用研究

研究了种植紫花苜蓿 (MedicagosativaL )在接种和不接种菌根真菌 (GlomuscaledoniumL )情况下对土壤中苯并 [a]芘 (B[a]P)的降解动态。历经 90天的温室盆栽试验表明 ,较高浓度 (10 0mgkg-1)B[a]P能降低菌根真菌对植物根的侵染率。种植紫花苜蓿和接种菌根真菌能促进土壤中可提取态B[a]P的降解 ,在接种情况下 ,有植物时对三种浓度 (1mgkg-1,10mgkg-1,10 0mgkg-1)B[a]P的降解率分别达 86 2 %、86 6 %、5 7 0 % ;而没有植物时B[a]P的降解率为 5 3 5 %、5 3 0 %、33 0 %。不接菌根真菌时的降解率比接菌根真菌的低得多 ,不接种菌根真菌时 ,有植物的B[a]P降解率分别达 75 9%、77 7%、5 3 4 % ;而不种植物的降解率分别为 5 4 9%、5 2 6 %、34 1% ,低、中浓度 (1mgkg-1,10mgkg-1)两处理的降解率明显地高于高浓度处理(p <0 0 5 )。B[a]P添加对土壤中多酚氧化酶活性有较大的影响 ,特别是高浓度B[a]P处理土壤的酶活性明显地低于其它三个处理 ,接种菌根真菌能够提高土壤中的酶活性 ,从而促进了土壤中B[a]P的降解。     

基于碳酸氢钠为碳源的氢自养反硝化去除地下水中硝酸盐研究

氢自养反硝化修复地下水中的硝酸盐污染以其清洁、环保又经济而受到广泛重视。利用全自动恒温振荡仪,以NaHCO3为碳源驯化氢自养反硝化细菌,并对影响氢自养反硝化速率的因素进行了研究。结果表明,以NaHCO3作为唯一的无机碳源,不仅可以高效驯化氢自养反硝化细菌,而且可以控制体系的pH值,效果优于单独以CO2或以CO2和NaHCO3共同为碳源的系统;当单独以NaHCO3为碳源时,其浓度为2g·L-1时可以满足氢自养反硝化细菌的生长,并使体系pH保持在8.5±0.2;当初始NO3--N浓度〈135.6mg·L-1时,反硝化速率随着NO3--N浓度的升高而增大,当NO3--N浓度过高时（〉135.6mg·L-1）,会抑制氢自养反硝化的进行;当pH在6.0～9.0时,氢自养反硝化可以进行,但其最适pH为7.0～8.0,而当pH〈6.0或pH〉9.0时,反硝化基本停滞;温度为35℃时反硝化速率最大,为2.83mg·L-·1h-1,当温度为15℃时,有明显的亚硝酸盐积累。     

联苯菊酯降解菌的筛选、鉴定及降解特性研究

联苯菊酯是一种广谱高效杀虫剂,大规模的应用使其广泛残留在环境中,因此筛选联苯菊酯的高效降解菌具有重要意义。从扬州农药厂附近的地表土壤取样,利用富集驯化培养分离得到一株编号为S8的降解细菌,经表形特征、生理生化特性和16S rDNA序列分析其为醋酸钙不动杆菌（Acinetobacter calcoaceticus）,该菌株在pH7.0和30 ℃的条件下,对100 mg·L-1联苯菊酯的3 d降解率达56.4%,半衰期为60.7 h。其最适生长条件为：pH6.0~8.0,温度30~35 ℃,接种量5%。研究结果可为今后治理联苯菊酯残留污染提供理论参考。     

一株硫酸盐还原菌DSRBa的分离鉴定及特性分析

从内循环厌氧反应器颗粒污泥中分离、纯化得到一株硫酸盐还原菌命名为DSRBa,经形态和基于16SrDNA序列分析,该菌株归属于脱硫弧菌属（Desulfovibrio）。分别以甲酸钠、乙醇、乳酸钠、葡萄糖等为碳源,以硫酸盐、硫代硫酸盐、亚硫酸盐、单质硫为硫源,研究了不同温度、pH及不同硫酸根浓度对该菌株的影响。结果表明,菌株最适宜生长温度为30～35℃,最佳生长pH为7.0,无需绝对严格厌氧,当溶液中氧化还原电位（ORP）≤-40mV时,该菌株能较好生长,且生长4d后使溶液内氧化还原电位值达到-380mV,随后溶液内氧化还原电位基本保持不变。当系统内乳酸钠和酵母提取物浓度分别为3.5g·L-1和1g·L-1时,硫酸根浓度在1～4.5g·L-1范围对菌株生长无明显影响,且当SO24-浓度≤3g·L-1时,菌株生长4d对硫酸根的去除率达到90%以上。     

采用Biolog, DGGE 和PLFA三种方法研究利用方式对土壤微生物群落结构的影响

Biolog, 16S rRNA gene denaturing gradient gel electrophoresis （DGGE）, and phospholipid fatty acid （PLFA） analyses were used to assess soil microbial community characteristics in a chronosequence of tea garden systems （8-, 50-, and 90- year-old tea gardens）, an adjacent wasteland, and a 90-year-old forest. Biolog analysis showed that the average well color development （AWCD） of all carbon sources and the functional diversity based on the Shannon index decreased （P 〈 0.05） in the following order： wasteland 〉 forest 〉 tea garden. For the DCCE analysis, the genetic diversity based on the Shannon index was significantly lower in the tea garden soils than in the wasteland. However, compared to the 90-year-old forest, the tea garden soils showed significantly higher genetic diversity. PLFA analysis showed that the ratio of Gram positive bacteria to Cram negative bacteria was significantly higher in the tea garden soils than in the wasteland, and the highest value was found in the 90-year-old forest. Both the fungal PLFA and the ratio of fungi to bacteria were significantly higher in the three tea garden soils than in the wasteland and forest, indicating that fungal PLFA was significantly affected by land-use change. Based on cluster analysis of the soil microbial community structure, all three analytical methods showed that land-use change had a greater effect on soil microbial community structure than tea garden age.     

农药浓度、共代谢底物和接种量对Sphingobium indicum B90A降解六六六效率的影响

有机氯农药六六六曾被广泛用于卫生防疫和对抗农业病虫害,但由于其毒性和持久性引发了一系列环境问题。鉴于微生物降解方法在农药污染场地的修复中具有重要作用,采用摇瓶培养法研究了在α-、β-、γ-和δ-六六六（HCH）异构体混合体系中,农药浓度、共代谢底物和接种量对Sphingobium indicum B90A降解4种HCH异构体的影响。研究结果表明：S.indicum B90A对α-和β-HCH的利用较好,其次是γ-和δ-HCH。在10mg·L-1混合HCH的无机盐培养液中,30℃下反应72h,S.indicumB90A对α-、β-、γ-和δ-HCH的降解率分别为99%、86%、53%和33%。随着HCH浓度的增加,S.indicum B90A对4种HCH异构体降解率均逐渐降低。在共代谢底物的研究中,添加葡萄糖或酵母粉均能明显地提高S.indicumB90A对HCH的降解能力,在10mg·L-1混合无机盐培养液中,添加100mg·L-1葡萄糖或添加50mg·L-1酵母粉,30℃下反应84h,S.indicum B90A对α-、β-、γ-和δ-HCH的降解率均接近100%。S.indicum B90A对HCH的降解率随着菌体接种量的增加而相应提高,适宜接菌量为5%。     

乙草胺降解菌Y-4的分离鉴定及降解特性研究

从长期经乙草胺污染的污泥中分离到一株能以乙草胺为唯一碳源和能源生长的菌株Y-4,通过生理生化实验和16S rDNA同源性序列分析,鉴定为申氏杆菌属（Shinella sp.）。采用室内培养方法,研究了Y-4对乙草胺的降解特性。结果表明,Y-4能有效地降解浓度为5～200 mg.L-1的乙草胺,在48 h内对50 mg.L-1乙草胺的降解率达到83.3%。菌株Y-4降解乙草胺的最适pH值为8.0,最适温度为30℃,其对丙草胺和丁草胺等农药也有良好的降解效果。