Removal of Phthalate Esters by Activated Sludge Inoculated with a Strain of Nocardia erythropolis

Phthalate esters, such as di-2-ethyl hexyl phthalate (DEHP) and di-n-butyl phthalate (DBP), were efficiently removed from wastewater by inoculating viable cells of Nocardia erythropolis, a bacterium capable of rapidly degrading phthalate esters, in activated sludge. When the wastewater containing 1500 ppm of DEHP was treated with the activated sludge inoculated with Nocardia erythropolis, the DEHP was found to be removed at a rate of 98.2% in 1 day and to be gas-chromatographically free on and after the 3rd day. Activated sludges, in particular, when high concentration of substances was used, were efficiently prevented from deflocculation of sludge by inoculation of Nocardia erythropolis, and moreover, the deflocked sludge was restored and recovered by the addition of Nocardia erythropolis.     

Degradation of Phthalate and Di-(2-Ethylhexyl)phthalate by Indigenous and Inoculated Microorganisms in Sludge-Amended Soil

The metabolism of phthalic acid (PA) and di-(2-ethylhexyl)phthalate (DEHP) in sludge-amended agricultural soil was studied with radiotracer techniques. The initial rates of metabolism of PA and DEHP (4.1 nmol/g [dry weight]) were estimated to be 731.8 and 25.6 pmol/g (dry weight) per day, respectively. Indigenous microorganisms assimilated 28 and 17% of the carbon in [¹⁴C]PA and [¹⁴C]DEHP, respectively, into microbial biomass. The rates of DEHP metabolism were much greater in sludge assays without soil than in assays with sludge-amended soil. Mineralization of [¹⁴C]DEHP to ¹⁴CO₂ increased fourfold after inoculation of sludge and soil samples with DEHP-degrading strain SDE 2. The elevated mineralization potential was maintained for more than 27 days. Experiments performed with strain SDE 2 suggested that the bioavailability and mineralization of DEHP decreased substantially in the presence of soil and sludge components. The microorganisms metabolizing PA and DEHP in sludge and sludge-amended soil were characterized by substrate-specific radiolabelling, followed by analysis of ¹⁴C-labelled phospholipid ester-linked fatty acids (¹⁴C-PLFAs). This assay provided a radioactive fingerprint of the organisms actively metabolizing [¹⁴C]PA and [¹⁴C]DEHP. The ¹⁴C-PLFA fingerprints showed that organisms with different PLFA compositions metabolized PA and DEHP in sludge-amended soil. In contrast, microorganisms with comparable ¹⁴C-PLFA fingerprints were found to dominate DEHP metabolism in sludge and sludge-amended soil. Our results suggested that indigenous sludge microorganisms dominated DEHP degradation in sludge-amended soil. Mineralization of DEHP and PA followed complex kinetics that could not be described by simple first-order equations. The initial mineralization activity was described by an exponential function; this was followed by a second phase that was described best by a fractional power function. In the initial phase, the half times for PA and DEHP in sludge-amended soil were 2 and 58 days, respectively. In the late phase of incubation, the apparent half times for PA and DEHP increased to 15 and 147 days, respectively. In the second phase (after more than 28 days), the half time for DEHP was 2.9 times longer in sludge-amended soil assays than in sludge assays without soil. Experiments with radiolabelled DEHP degraders suggested that a significant fraction of the ¹⁴CO₂ produced in long-term degradation assays may have originated from turnover of labelled microbial biomass rather than mineralization of [¹⁴C]PA or [¹⁴C]DEHP. It was estimated that a significant amount of DEHP with poor biodegradability and extractability remains in sludge-amended soil for extended periods of time despite the presence of microorganisms capable of degrading the compound (e.g., more than 40% of the DEHP added is not mineralized after 1 year).     

固定化微球降解土壤中PAEs效果及影响因素

旨为研究土壤邻苯二甲酸酯污染修复中,固定化微球降解土壤中邻苯二甲酸酯的效果及影响因素。以海藻酸钠为载体,采用包埋法对课题组前期提取的微小杆菌进行固定化,比较固定化微球和游离菌降解土壤中邻苯二甲酸酯(Phthalates esters,PAEs)的效果及pH、温度、重金属、无机盐等对降解菌降解目标物的影响。结果显示:(1)在土壤环境相同条件下,固定化微球对邻苯二甲酸二甲酯(Dimethyl ortho-phthalate,DMP)、邻苯二甲酸二正丁酯(Di-n-butyl ortho-phthalate,DnBP)和邻苯二甲酸二(2-乙基己)酯(Bis(2-ethylhexyl)ortho-phthalate,DEHP)的降解效果高于游离菌,DMP在7 d可降解完全,DnBP在10 d内可降解完全,DEHP在20 d降解率63.73%;而游离菌则在15 d内完全降解DMP,20 d内完全降解DnBP,DEHP在20 d降解率48.77%;(2)不同pH值时,固定化微球对DMP、DnBP、DEHP的降解率均高于游离菌,pH9时,固定化微球对于DMP、DnBP、DEHP的降解率最高分别为96.81%、89.39%、58.35%;(3)不同温度,固定化微球对DMP、DnBP、DEHP的降解率也均高于游离菌,温度为30℃时,固定化微球对于DMP、DnBP、DEHP的降解效率达到最高,分别为96.27%、89.19%、59.01%;(4)重金属使游离菌对DMP、DnBP、DEHP降解率下降较多,而使固定化微球对DMP、DnBP的降解率仅下降了16.35%、9.95%,DEHP不仅没有降低,反而增加2.49%,说明重金属对游离菌起到很强的抑制作用,但对于固定化微球的降解效果影响较小;(5)盐碱条件下,中性盐极大降低了游离菌和固定化微球降解DMP、DnBP、DEHP的降解能力,碱性盐和混合盐对降解菌影响较小,且增强了固定化微球对DnBP、DEHP的降解能力。固定化微球降解PAEs效果明显高于游离菌,对外界环境有更好的适应能力,且对重金属、无机盐污染环境有一定的抵御能力。     

Efficiency of Indigenous and Inoculated Cold-Adapted Soil Microorganisms for Biodegradation of Diesel Oil in Alpine Soils

Biodegradation of diesel oil (5 g(middot)kg [soil dry weight](sup-1)) was investigated in five alpine subsoils, differing in soil type and bedrock, in laboratory experiments during 20 days at 10(deg)C. The biodegradation activities of the indigenous soil microorganisms and of a psychrotrophic diesel oil-degrading inoculum and the effect of biostimulation by inorganic fertilization (C/N/P ratio = 100:10:2) were determined. Fertilization significantly enhanced diesel oil biodegradation activity of the indigenous soil microorganisms. Biostimulation by fertilization enhanced diesel oil biodegradation to a significantly greater degree than bioaugmentation with the psychrotrophic inoculum. In none of the five soils did fertilization plus inoculation result in a higher decontamination than fertilization alone. A total of 16 to 23% of the added diesel oil contamination was lost by abiotic processes. Total decontamination without and with fertilization was in the range of 16 to 31 and 27 to 53%, respectively.     

Shake Flask Biodegradation of 14 Commercial Phthalate Esters

An acclimated shake flask CO₂ evolution test was used to study the biodegradability of 14 commercial phthalate esters that are commonly used as plasticizers. Both CO₂ evolution (ultimate biodegradation) and loss of parent phthalate esters (primary biodegradation) were measured. With only a few exceptions, primary biodegradation was 90% or higher, and ultimate biodegradation was in excess of 55% of theoretical results in 28 days. The results showed that all of the commercial phthalate esters were susceptible to biodegradation by mixed populations of microorganisms from natural sources. The results also provide considerable insight into the utility and reproducibility of a standard biodegradation test that is being recommended for widespread screening of chemicals.     

Activated Sludge Biodegradation of 12 Commercial Phthalate Esters

The activated sludge biodegradability of 12 commercial phthalate esters was evaluated in two test systems: (i) a semicontinuous activated sludge test and (ii) an acclimated 19-day die-away procedure. Both procedures demonstrated that phthalate esters are rapidly biodegraded under activated sludge conditions when loss of the parent phthalate ester (primary degradation) is measured.     

Comparative Volatile Profiles in Soy Sauce According to Inoculated Microorganisms

We compared the volatile profiles in soy sauce according to inoculation with Tetragenococcus halophilus and/or Zygosaccharomyces rouxii. Totals of 107 and 81 volatiles were respectively identified by using solid-phase microextraction and solvent extraction. The various volatile compounds identified included acids, aldehydes, esters, ketones, furans and furan derivatives, and phenols. The major volatiles in the samples treated with T. halophilus were acetic acid, formic acid, benzaldehyde, methyl acetate, ethyl 2-hydroxypropanoate, 2-hydroxy-3-methyl-2-cyclopenten-1-one, and 4-hydroxy-3-methoxybenzaldehyde, while those in the samples inoculated with Z. rouxii were mainly ethanol, acetaldehyde, ethyl propanoate, 2/3-methylbutanol, 1-butanol, 2-phenylethanol, ethyl 2-methylpropanoate, and 4-hydroxy-2-ethyl-5-methyl-3(2H)-furanone. The results indicate that T. halophilus produced significant acid compounds and could affect the Z. rouxii activity, supporting the notion that yeasts and lactic acid bacteria respectively have different metabolic pathways of alcoholic fermentation and lactic acid fermentation, and produce different dominant volatile compounds in soy sauce.     

Distribution of Phthalate Esters in Sediments of Kaohsiung Harbor,Taiwan

The major objectives of this research are to study the species and concentration of phthalate esters (PAEs), an organic endocrine disruptor, in the sediments of Kaohsiung Harbor, Taiwan. Twenty monitoring stations were installed in the waterways of Kaohsiung Harbor to collect sediment samples for analyzing six species of PAEs. Results of laboratory analyses show that concentrations of ΣPAE₆ in the harbor sediment are between 0.40 and 34.8 mg/kg with an average of 5.02 mg/kg. Among all chemicals, di-(2-ethylhexyl) phthalate (DEHP) is the major species that constitutes 92% of all chemicals found in the sediment. Where the spatial distribution of the chemicals is concerned, all rivers (i.e., Love River, Canon River, and Salt River) show the highest concentrations near the mouth where they discharge into the harbor. This indicates that major sources of pollution originate from the upstream municipal and industrial wastewater discharges. Distributions of PAEs during both wet and dry seasons show that PAEs are more easily disbursed in the receiving sea water, leading to a wider range of chemical distribution, and hence most of the chemicals are accumulated in the harbor water channel. The assessment of ecological toxicity indicates that concentrations of the 88% DEHP found in the sediment are higher than environmental risk limits (ERLs), implying that the Kaohsiung Harbor sediments pose potential risks to the local ecological system. Hence, an effective PAE management and control strategy must be developed and implemented in order to improve the harbor sediment quality, and keep the harbor ecological environment free from the interference of chemicals that interrupt endocrine hormones.     

Effect of Different Ammonia Concentrations on Community Succession of Ammonia-oxidizing Microorganisms in a Simulated Paddy Soil Column

Ammonia oxidation is performed by both ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). To explore the effect of ammonia concentration on the population dynamic changes of ammonia-oxidizing microorganisms, we examined changes in the abundance and community composition of AOA and AOB in different layers. Most of the archaeal amoA sequences were Nitrosotalea-related and the proportion that Nitrosotalea cluster occupied decreased in the surface layer and increased in the deep layer during the cultivation process. Nitrosopumilus-related sequences were only detected in the deep layer in the first stage and disappeared later. Both phylogenetic and quantitative analysis showed that there were increased Nitrosomonas-related sequences appeared in the surface layer where the ammonia concentration was the highest. Both AOA and AOB OTU numbers in different layers decreased under selective pressure and then recovered. The potential nitrification rates were 25.06 μg·N·L(-1)·g(-1) dry soil·h(-1) in the mid layer which was higher than the other two layers. In general, obvious population dynamic changes were found for both AOA and AOB under the selective pressure of exogenous ammonia and the changes were different in three layers of the soil column.     

酞酸酯污染农田土壤生物修复研究进展

酞酸酯是目前世界上产量最大、应用面积最广的人工合成有机物,作为塑化剂被广泛应用于塑料制品中。近年来发现酞酸酯是一类典型的环境内分泌干扰物。随着生活中塑料制品日益增多,尤其是农用薄膜和有机肥的大量使用,农田土壤中酞酸酯污染日益加剧,酞酸酯污染土壤的修复逐渐引起国内外学者的广泛关注。生物修复具有价格低廉、效果良好和环境友好等特点,尤其适合于大面积污染农田土壤修复。从植物修复、微生物修复、植物微生物联合修复和动物修复等方面综述了国内外酞酸酯污染土壤生物修复的研究现状,并从高效修复植物筛选及机理探讨、实际污染土壤的降解菌修复研究、高效降解菌群的构建和作用机制等方面对该领域的研究进行了展望,以期为酞酸酯污染土壤的修复研究提供借鉴并拓展新的思路。     

Rates of Transformation of Methyl Parathion and Diethyl Phthalate by Aufwuchs Microorganisms

Using batch cultures, we determined transformation rates for low concentrations of two toxicants—an insecticide, methyl parathion (O,O-dimethyl O-p-nitrophenyl phosphorothioate), and a plasticizer, diethyl phthalate—by aufwuchs, aquatic microbial growth attached to submerged surfaces or suspended in streamers or mats. Aufwuchs samples were collected from field sites, an indoor channel, and a continuous-flow fermentor. Aufwuchs fungi, protozoa, and algae did not transform methyl parathion or diethyl phthalate, but bacteria rapidly transformed both chemicals. Second-order transformation rate coefficients, K_b, based on total plate counts of bacteria in aufwuchs, were determined for potential use in a mathematical model capable of predicting the transport and fate of chemicals in aquatic systems. K_b for both methyl parathion and diethyl phthalate decreased as the concentration of total bacteria, [B], increased in aufwuchs. This effect resulted from the proportion of nontransformer to transformer bacteria increasing as [B] increased and from the rate of transformation per transformer cell decreasing as [B] increased. First-order transformation rate coefficients, K₁, were relatively stable per unit of surface area colonized by aufwuchs, because K_b decreased as [B] increased (K₁ = K_b × [B]).     

Succession of Chitinolytic Microorganisms in Chernozem Soil

Microbiology - The chitinolytic prokaryotic and eukaryotic microbial complex of chernozem soil has been investigated in the course of a succession initiated by the introduction of chitin and...     

Removal of Cadmium by Microorganisms in a Two-Stage Chemostat

A two-stage chemostat was used to study removal of cadmium by microorganisms in continuous culture. The medium was contaminated with 0.8 mg of Cd per liter. At 20°C, most of the microbial biomass formed aggregates which settled in the second stage of the chemostat. Effluent was free of bacteria. Up to 80% of the metal contained in the inlet flux was removed by the biomass, with 20% remaining in solution. At 10°C and with a shorter retention time, flocculation was poorer and metal removal by settling biomass did not exceed 35%.     

Sorption of Cadmium by Microorganisms in Competition with Other Soil Constituents

The fate of cadmium in soil is influenced to a great extent by microbial activity. Microorganisms were compared with abiotic soil components for their ability to sorb Cd from a liquid medium. When the same amount (on a dry weight basis) of bacterial cells (Serratia marcescens and Paracoccus sp.), clay (montmorillonite), or sand was separately incubated in 0.05 M phosphate buffer, pH 7.2, containing 10 ppm of Cd (10 μg/ml), bacterial cells removed the largest quantity of Cd. Dead cells sorbed much more Cd from the medium than live cells. A comparative study of Cd removal from the medium by seven soil bacteria and four fungi did not indicate appreciable differences. With increasing microbial biomass, the relative efficiency of 0.1 M NaOH as an extractant of sorbed Cd increased, whereas the extraction efficiency of 0.005 M DTPA (diethylenetriaminepentaacetic acid) decreased. It appeared that NaOH and DTPA extracted different chemical forms of Cd. This assumption was supported by vastly different correlation coefficients in the relative amount of Cd extracted by the two solvents.     

气相色谱质谱法测定食品包装材料中24种邻苯二甲酸酯(英文)

目的:建立同时检测食品包装材料中24种邻苯二甲酸酯类化合物的气相色谱质谱法(GC-MS)分析方法。方法:用正己烷提取包装材料,GC-MS选择离子监测模式(SIM)测定,运用气质联用仪测定24种邻苯二甲酸酯类物质。结果:24种邻苯二甲酸酯类物质的线性范围为0.05 mg/L~10 mg/L,除了邻苯二甲酸二异壬酯(DINP)和邻苯二甲酸二异癸酯(DIDP)为0.5 mg/L~10 mg/L,相关系数(r2)除DINP、DIDP外均大于0.99,方法的检出限(信噪比为3)为0.002 mg/kg~0.05 mg/kg,在食品包装材料基质中3个加标水平的平均回收率为85.2%~108%,相对标准偏差(RSD,n=6)为5.9%~10.2%。结论:该方法快速、灵敏、准确可靠,适用于食品包装材料中邻苯二甲酸酯类化合物的分析检测。     

接菌壮秧剂对低磷土壤水稻秧苗生理生化特性的影响

通过苗床培养试验,研究了在低磷土壤上接菌壮秧剂对水稻品种东农423秧苗生理生化特性的影响.结果表明,在低磷土壤上施用接种5406放线菌和溶磷青霉菌P77的壮秧剂可增加植株地上部的含磷量和吸磷量,减少根部的含磷量和吸磷量;提高水稻秧苗的硝酸还原酶活性,增加可溶性糖和可溶性蛋白质的含量,减少硝态氮在植物体内的积累;其Chl a、Chl b、Chl a Chl b和类胡萝卜素含量呈降低趋势,但Chl a/Chl b比值的变化不明显;以上各指标除根部含磷量和Chl a/Chl b外,其它与对照差异均达到极显著水平(P<0.01).研究发现,接菌壮秧剂可以有效改善水稻秧苗的磷素营养状况,且接种P77的效果好于5406,2种菌的接种浓度均以5×107cfu/g效果较佳.     

喀斯特土壤上香樟幼苗接种不同AM真菌后的耐旱性效应

为探索喀斯特土壤适生植物香樟幼苗在接种不同AM真菌后的耐旱适应性,进行了香樟幼苗接种幼套球囊霉(Glomus etunicatum)和层状球囊霉(Glomus lamellosum)后水分胁迫处理试验。结果表明：（1）接种AM真菌显著提高了香樟幼苗的生物量积累,AM促进植株生物量效应依次为中度>轻度>正常>重度,同一水分胁迫处理下生物量幼套球囊霉>层状球囊霉。（2）中度干旱下香樟幼苗菌根依赖性最大,幼套球囊霉接种植株的菌根依赖性较层状球囊霉大。（3）接种AM真菌显著提高了植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量,并降低了丙二醛含量;在正常供水下植株叶片可溶性糖、可溶性蛋白质和脯氨酸含量层状球囊霉接种>幼套球囊霉接种>对照,干旱胁迫下表现为幼套球囊霉接种>层状球囊霉接种>对照;干旱胁迫下的幼套球囊霉接种植株丙二醛含量低于层状球囊霉接种植株。（4）总体上,可溶性糖与脯氨酸相关性极显著,可溶性蛋白质与丙二醛之间呈显著负相关性。幼套球囊霉接种香樟幼苗的耐旱性高于和层状球囊霉接种香樟幼苗。     

Bioaugmentation with Immobilized Microorganisms to Enhance Phytoremediation of PCB-Contaminated Soil

The aim of this study was evaluate the effect of bioaugmentation by free and immobilized strains of microbial consortium on the phytoremediation of polychlorinated biphenyl (PCB)-contaminated soil using the Avena sativa, Brachiaria decumbens, Brassica juncea, and Medicago sativa plants. Alginate and biochar were used as carrier materials and free cells were used as the control. PCBs 44, 66, 118, 138, 153, 170, and 180 were chosen as indicator PCB congeners. After 60 days of plant growth, the concentration of each congener and the survival of the microbial inoculum were evaluated. The removal of the PCB congener was greater in B. juncea planted treatments and using biochar as a carrier material. PCB 66 was the congener with the highest removal percentage in all using biochar and alginate-immobilized microorganisms and free microorganisms, while PCB 170 had the lowest removal percentage in all treatments. The largest removal percentage for all congeners was obtained using biochar as a carrier material (7.2–30.3%) and the lowest with planted treatments using free microorganisms (2.3–6.8%). Real-time polymerase chain reaction (PCR) showed that the microbial inoculum survived when it was immobilized using both alginate and biochar without any significant differences between treatments; however, PCB removal percentages were obtained with biochar, which demonstrated that this carrier material has a positive effect on microbial activity.     

Solubilization of Iron-Containing Minerals by Soil Microorganisms

Eighty-eight strains of microorganisms were isolated from soils collected in northern and southern Chile, and 10 fungi which showed the highest solubilizing action upon the iron in granodiorite were then selected. These fungi were incubated with the following iron-containing minerals: augite, hornblende, biotite, magnetite, hematite, and the igneous rock granodiorite. The solubility of iron in these minerals depended on their nature, crystalline structure, the concentration of metabolic products, or all three. Complex formation could be the mechanism involved, as a strong cation-exchange resin was not able to extract Fe from culture solutions. This conclusion is also confirmed by the R(F) values obtained by thin-layer chromatography of iron-containing culture solutions.