沈阳市源分类生物有机垃圾的生物降解力研究

在实验室研究城市生物有机垃圾好氧和厌氧处理的生物降解能力,分析反应物质的输入和输出,研究好氧堆肥及厌氧消化反应过程中的参数变化,并得出相关结论:(1)堆肥过程中,箱体温度可以达到55℃以上,并持续3 d以上,达到无害化处理;堆肥过程中物料的pH值先降低后升高,最终稳定呈弱碱性,弱碱性pH值有利于提高土壤中阳离子交换能力,提高土壤肥力;(2)源分类后城市生物有机垃圾在堆肥处理的第一周减量化最明显,为21.23%,明显高于后2周,好氧生物降解率平均为63.20%;(3)沈阳市源分类生物有机垃圾实验室沼气产量为619 m3/(t VS),其中甲烷浓度平均为54.36%,沼气生物能为19.52 MJ/m3,厌氧生物降解率为70.14%。

链长和阳离子对胆碱脂肪酸皂的细胞毒性和生物降解力的影响

与钠皂和钾皂相比,在脂肪酸表面活性剂中使用胆碱作为抗衡离子可大大提高其水溶性,使长链脂肪酸衍生物在环境温度下得到应用。虽然胆碱已证实具有高生物相容性和低生物毒性,但根据欧洲化妆品管理规范76/768/EEC,所有化妆品均禁止使用胆碱盐。为了促进其应用,根据OCDE 301F标准研究了烷基链长为m=12~18的胆碱脂肪酸皂(ChCm)的生物降解性。对于奇数碳和偶数碳脂肪酸,测定了m=8~16的ChCm表面活性剂的细胞毒性。此外,为了更好与普通肥皂比较,并阐明阳离子的影响,还研究了钠和钾的同系物,揭示了疏水链长度与IC50(半抑制浓度)值之间的非线性关系。重要的是,实验数据表明ChCm表面活性剂的IC50值与广泛使用的钠皂和钾皂的IC50值一致。这表明胆碱羧酸盐表面活性剂是无害的,证明了其在终端消费品中的应用潜能。

蚯蚓对农村有机生活垃圾分解处理的研究

本文以农村有机生活垃圾为研究对象,根据蚯蚓的生活习性设计了4个不同组分的试验基质,这些基质的主要成分为厨余垃圾,辅料为猪粪、牛粪和土壤。本试验引进"大平二号"赤子爱胜蚓(Eisenia foetida)在室内进行盆养试验,同时以未放养蚯蚓处理的试验基质作为对照,培养周期为5周。研究表明,蚯蚓分解新鲜有机生活垃圾的效果最好,其生物降解率达到75.688%,该试样中蚯蚓日增重倍数和日增值倍数也最大。经蚯蚓处理后的各基质肥效都有所增加,试验样基质中有机碳、氮磷含量相对于对照样都有所升高,试验样中碱解氮含量是对照样的3倍左右。新鲜有机生活垃圾基质C/N比最大,其速效磷含量也为最大值。同时,蚯蚓还对各基质的重金属有富集作用,其富集效果都在48%左右。各组之间的试验结果大多存在显著性差异(P<0.05)。

城市有机垃圾蚯蚓堆肥处理的实验研究

采用蚯蚓堆肥处理4种不同有机废物,通过分析样品的温度、有机分含量、pH值以及实验前后样品的质量等参数的变化,比较蚯蚓堆肥处理不同有机垃圾的效果。实验结果表明:1.在合理条件下,蚯蚓堆肥可以直接处理生活有机垃圾和污泥(包括其堆肥后产物);2.在同样的实验条件下,蚯蚓堆肥处理生活有机垃圾和污泥及其堆肥后产物过程中,其处理城市生活有机垃圾的效果最好,减量化和物降解率分别为69.8%和75%。

Effect of heat treatment on microstructure, mechanical properties and in vitro degradation behavior of as-extruded Mg-2.7Nd-0.2Zn-0.4Zr alloy

Mg-2.7Nd-0.2Zn-0.4Zr （mass fraction, %） alloy was designed for degradable biomedical material. The ingots of the alloy were solution treated and then hot extruded. The extruded rods were heat treated with aging treatment, solution treatment and solution＋aging treatment, respectively. Microstructures of the alloy were observed by optical microscopy （OM） and scanning electron microscopy （SEM）. Mechanical properties at room temperature were tested. In vitro degradation behavior of the alloy immersed in simulated body fluid was measured by hydrogen evolution and mass loss tests. The degradation morphologies of the alloy with and without degradation products were observed by SEM. The results show that the grains grow apparently after solution treatment. Solution treatment improves the elongation of as-extruded alloy significantly and decreases the strength, while aging treatment improves the strength and reduces the elongation of the alloy. The yield ratio is reduced by heat treatment. The in vitro degradation results of the alloy show that solution treatment on the as-extruded alloy results in a little higher degradation rate and aging treatment on the alloy can reduce degradation rate slightly.

PROPERTIES OF BIODEGRADABLE THERMOPLASTIC STARCH

Thermoplastic starch is a kind of modified starch produced by mixing starch with additives and processing the mixture in an extruder. The mechanical properties, including tensile strength and elongation at break, biodegradability and rheological properties were studied. Glycerol and urea, to some extent, can both decrease the tensile strength and increase percentage elongation at break, because the former acts as a plasticizer and the latter can break down interactions among starch macromolecules. Thermoplastic starch shows thermoplasticity and its melt behaves as a pseudoplastic liquid at a low shear rate. Its biodegrading extent is slightly higher than that of native starch. The molecular weight of starch displays a decreasing tendency after thermoplastic modification.

蚯蚓处理农村家畜粪便及有机生活垃圾的试验研究

本研究以农村家畜粪便和有机生活垃圾为研究对象,设计了6个不同组合的农村有机废弃物作为基质混入土壤,同时引进日本"大平二号"赤子爱胜蚓(Eisenia foetida)进行盆养试验。结果表明:蚯蚓对农村有机废弃物的减量效果为:3组>2组>1组>6组>5组>4组。蚯蚓分解处理未预处理有机生活垃圾的生物降解率最高,达到75.688%。蚯蚓的日增重倍数和日增值倍数在预处理的有机生活垃圾组合中最低,在未预处理的有机生活垃圾组合中最高,未预处理的有机生活垃圾组合中蚯蚓日增重倍数是0.139,日增值倍数0.177。不同基质的土壤中,有机碳、总氮、总磷、速效氮、速效磷增加,有机质、C/N比降低,未预处理的有机生活垃圾组合pH增加,其余各组合均有降低;本试验结束后各组合蚯蚓体内重金属Cu和Zn的含量超过其作为饲料的标准。

Isolation, Identification and Biodegradation Characteristics of a Phthalate Ester Degrading Bacterium

By using plate screening techniques with five phthalate esters （DMP, DEP, DBP, DEHP and DOP） as energy and carbon sources, an active strain was isolated from the sediments of Chaohu Lake, which was identified as Burkholderia pickettil and named B. pickettii.z-1. The biodegradation of five phthalate esters by B. pick- ettii.z-1 strain was in accordance with the pseudo first-order kinetic equation： Ct = C0.e-kt. As the concentration of phthalate esters increased, the degradation rate of phthalate esters was reduced. B. pickettii.z-1 strain exhibited remarkably different degradation effects on various PAEs. Specifically, short-side-chain DMP and DEP were degraded rapidly, while long-side-chain DBP and DEHP were degraded slowly.

蚯蚓处理农村生活垃圾的试验研究

随着新农村的建设和发展,农村有机生活垃圾的资源化利用已经成为一个重要的议题。本文以通过蚯蚓处理农村有机生活垃圾为研究对象,结果表明,蚯蚓处理农村有机废弃物的减量效果中蚯蚓分解处理未预处理有机生活垃圾的生物降解率最高,达到75.688%;蚯蚓的日增重倍数和日增值倍数在预处理的有机生活垃圾组份中最低,在未预处理的有机生活垃圾组份中最高,未预处理的有机生活垃圾组份中蚯蚓日增重倍数是0.139,日增值倍数0.177。

Microstructure and properties of biodegradable β-TCP reinforced Mg-Zn-Zr composites

Magnesium alloys have good biocompatibility, but their mechanical properties and corrosion resistance may not be satisfied for using as degradable materials within bone due to its high corrosion rate in the physiological environment. Nano β-TCP particles were added into Mg-Zn-Zr alloy to improve its microstructure and the properties. As-extruded Mg-3Zn-0.8Zr alloy and Mg-3Zn-0.8Zr/xβ-TCP （x=0.5%, 1.0% and 1.5%） composites were respectively fabricated. The grains of Mg-Zn-Zr/β-TCP composites were significantly refined. The results of the tensile tests indicate that the ultimate tensile strength and the elongation of composites were improved with the addition of β-TCP. The electrochemical test result in simulation body fluid shows that the corrosion resistance of the composites was strongly enhanced comparing with that of the alloy. The corrosion potential of Mg-3Zn0.8-Zr/1.0β-TCP composite is 1.547 V and its corrosion current density is 1.20×10 6 A/cm 2 .

Biodegradation Kinetics of DDT in Soil under Different Environmental Conditions by Laccase Extract from White Rot Fungi

Biodegradation of 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane(DDT)in soil by laccase extract from white rot fungi under different experimental conditions was investigated.DDTs,which stands for the sum of p,p′-DDE,o,p′-DDT,p,p′-DDD and p,p′-DDT in soil was degraded efficiently,and the residue decreased rapidly during the first 15 days and then slowly during the period of 16-25 days.The biodegradation of DDTs in soil fitted the pseudo-first-order kinetics.For 5,10,15 and 25 days of incubation with laccase,the residue of DDTs in soil under different atmospheres was decreased by 20%-33%,34%-52%,41%-61%and 41%-69%respectively,under different flooding conditions that was decreased by 12%-17%,17%-30%,30%-45%and 35%-52%respectively, and for different soils that was decreased by 25%-34%,39%-53%,44%-58%and 47%-62%respectively.The half-life of DDTs in soil ranged from 15.07 to 32.95 days under O2,air or N2 atmospheres,23.07 to 40.71 days under different flooding conditions,and 18.78 to 28.88 days for different soils.Laccase is an efficient and safe agent for bioremediation of DDT-contaminated soil.

Optimization of Two-species Whole-cell Immobilization System Constructed with Marine-derived Fungi and Its Biological Degradation Ability

Mycelia pellet formed spontaneously in the process of cultivation was exploited as a biological carrier for whole-cell immobilization due to its unique structural characteristic. An innovative two-species whole-cell im- mobilization system was achieved by inoculating the marine-derived fungus Pestalotiopsis sp. J63 spores into cul- ture medium containing another fungus Penicillium janthinellum P1 pre-grown mycelia pellets for 2 days without any pretreatment. In order to evaluate the biological degradation capacity of this novel constructed immobilization system, the immobilized pellets were applied to treat paper mill effluent and decolorize dye Azure B. The use of the constructed immobilization system in the effluent resulted in successful and rapid biodegradation of numerous in- soluble fine fibers. The optimum conditions of immobilized procedure for maximum biodegradation capacity were determined using orthogonal design with biomass of P1 pellets 10 g （wet mass）, concentration of J63 spore 2x109 mlq, and immobilization time 2 d. The results demonstrate that immobilized pellets have more than 99% biodegradation capacity in a ten-hour treatment process. The kinetics of biodegradation fits the Michaelis-Menten equation well. Besides, the decolorization capability of immobilized pellets is more superior than that of P1 mycelia pellets. Overall, the present study offers a simple and reproducible way to construct a two-species whole-cell immobiliza- tion system for sewage treatment.

In vitro biodegradability and biocompatibility of porous Mg-Zn scaffolds coated with nano hydroxyapatite via pulse electrodeposition

The biodegradability and biocompatibility of porous Mg-2Zn（mass fraction, %） scaffolds coated with nano hydroxyapatite（HAP） were investigated. The nano HAP coating on Mg-2Zn scaffolds was prepared by the pulse electrodeposition method. The as-deposited scaffolds were then post-treated with alkaline solution to improve the biodegradation behavior and biocompatibility for implant applications. The microstructure and composition of scaffold and nano HAP coating, as well as their degradation and cytotoxicity behavior in simulated body fluid（SBF） were investigated. The post-treated coating is composed of needle-like HAP with the diameter less than 100 nm developed almost perpendicularly to the substrate, which exhibits a similar composition to natural bone. It is found that the products of immersion in SBF are identified to be HAP,（Ca,Mg）3（PO4）2 and Mg（OH）2. The bioactivity, biocompatibility and cell viabilities for the as-coated and post-treated scaffold extracts are higher than those for the uncoated scaffold. MG63 cells are found to adhere and proliferate on the surface of the as-coated and post-treated scaffolds, making it a promising choice for medical application. The results show that the pulse electrodeposition of nano HAP coating and alkaline treatment is a useful approach to improve the biodegradability and bioactivity of porous Mg-Zn scaffolds.

Pharmacokinetics and Biodegradation of Chitosan in Rats

Chitosan, an excellent biomedical material, has received a widespread in vivo application. In contrast, its metabolism and distribution once being implanted were less documented. In this study, the pharmacokinetics and biodegradation of fluorescein isothiocyanate(FITC) labeled and muscle implantation administrated chitosan in rats were investigated with fluorescence spectrophotometry, histological assay and gel chromatography. After implantation, chitosan was degraded gradually during its distribution to diverse organs. Among the tested organs, liver and kidney were found to be the first two highest in chitosan content, which was followed by heart, brain and spleen. Urinary excretion was believed to be the major pathway of chitosan elimination, yet 80% of chitosan administered to rats was not trackable in their urine. This indicated that the majority of chitosan was degraded in tissues. In average, the molecular weight of the degradation products of chitosan in diverse organs and urine was found to be <65 k Da. This further confirmed the in vivo degradation of chitosan. Our findings provided new evidences for the intensive and safe application of chitosan as a biomedical material.

Lubricant Biodegradation Enhancers: Designed Chemistry and Engineered Technology

In recent decades, a growing worldwide trend of developing the biodegradable lubricants has been prevailing to form a specific field of green chemistry and green engineering. Enhancement of biodegradability of unreadily biodegradable petroleum-based lubricants has as such become an urgent must. For over a decade the authors have been focusing on the improvement of biodegradability of unreadily biodegradable lubricants such as petroleum-based lubricating oils and greases. A new idea of lubricant biodegradation enhancer was put forward by the authors with the aim to stimulate the biodegradation of unreadily biodegradable lubricants by incorporating the enhancer into the lubricants in order to turn the lubricants into greener biodegradable ones and to help in situ bioremediation of lubricant-contaminated environment. This manuscript summarizes our recent efforts relating to the chemistry and technology of biodegradation enhancers for lubricants. Firstly, the chemistry of lubricant biodegradation enhancers was designed based on the principles of bioremediation for the treatment of hydrocarbon contaminated environment. Secondly, the ability of the designed biodegradation enhancers for increasing the biodegradability of unreadily biodegradable industrial lubricants was investigated through biodegradability evaluation tests, microbial population analysis, and biodegradation kinetics modeling. Finally, the impact of biodegradation enhancers on some crucial performance characteristics of lubricants such as lubricity and oxidation stability was tested via tribological evaluation and oxidation determinations. Our results have shown that the designed chemistry of nitrogenous and/or phosphorous compounds such as lauroyl glutamine, oleoyl glycine, oleic diethanolamide phosphate and lauric diethanolamide borate was outstanding in boosting biodegradation of petroleum-based lubricants which was ascribed to increase the microbial population and decrease the oil-water interfacial tension during the biodegradation process. Lubricants doped with the biodegradation enhancers exhibited much better biodegradability and higher biodegradation rate in the surrounding soils which could be well modeled by the exponential biodegradation kinetics. Furthermore, as lubricant dopants, the biodegradation enhancers also provided excellent capability in reducing friction and wear and in retarding oxidation of lubricants. In the nature of things, lubricant biodegradation enhancers, which are multi-functional not only in the improvement of biodegradability, but also in the fortification of lubricity and in the inhibition of oxidation of lubricants, are expected to be promising as a new category of lubricant additives.

Biodegradation of Petroleum Hydrocarbon by Pseudomonas Aeruginosa

A bacterial strain of the genus Pseudomonas aeruginosa was inoculated into a hydrocarbon culture medium and incubated for a definite period of time. The ability of the bacterial strain to biodegrade a hydrocarbon, viz. n-hexadecane, was evaluated through determining the hexadecane concentration in the inoculated culture medium on a gas chromatograph (GC). The effect of pH value on the degrading ability of the bacterial isolate and the impact of temperature on microbial growth were also explored. Test results showed that Pseudomonas aeruginosa was markedly effective in biodegrading n-hexadecane. Furthermore, the ability of Pseudomonas aeruginosa to biodegrade n-hexadecane was different at various pH values. Pseudomonas aeruginosa provided excellent degrading ability at a pH value of 7.0. The microbial cells of Pseudomonas aeruginosa increased with an increasing incubation duration at temperatures ranging from 28 ℃ to 35 ℃, and an exponential phase of microbial growth was observed.

Effects of Substrate Permeation on Kinetics of Phenol Biodegradation

Based on the theory of substrate permeation through the cytoplasmic membrane,and considering the effect of initial concentration of substrate,a new kinetic model of phenol degradation process was proposed,Comparing with the widely used Haldane model,which is greatly dependent on the initial phenol concentration,our model can be used to simulate the phenol degradation process in a wide range of initial phenol concentration by using only one set of model parameters ,Therefore,this new kinetic model has much more potential applications to industrial design and operation.

Biodegradation Kinetics for Pre-treatment of Klebsiella pneumoniae Waste with Autothermal Thermophilic Aerobic Digestion

Biodegradation parameters and kinetic characteristics for pre-treating waste strains of Klebsiella pneu-moniae were studied in laboratory scale with an insulated reactor by an innovative technique,autothermal thermo-philic aerobic digestion(ATAD) . Based on an Arrhenius-type equation,an empirical model was developed to corre-late the removal of total suspended solid(TSS) with the initial TSS concentration,influent reaction temperature,aeration rate and stirring rate. The reaction temperatures of the ATAD system could be raised from the ambient temperatures of 25 °C to a maximum temperature of 65 °C. The exponentials for the initial TSS concentration,aeration rate and stirring rate were 1.579,-0.8175 and-0.6549,respectively,and the apparent activation energy was 6.8774 kJ·mol-1. The correlation coefficient for the pre-exponential factor was 0.9223. The TSS removal effi-ciency predicted by the model was validated with an actual test,showing a maximum relative deviation of 10.79%. The new model has a good practicability.

Biodegradability of leachates from Chinese and German municipal solid waste

The quantitative and qualitative composition of Chinese municipal solid waste (MSW) differs significantly from German waste. The focus of this paper is on whether these differences also lead to dissimilar qualities of leachates during storage or landfilling. Leachates ingredients determine the appropriate treatment technique. MSW compositions of the two cities Guilin (China) and Essen (Germany), each with approx. 600 000 inhabitants, are used to simulate Chinese and German MSW types. A sequencing batch reactor (SBR) is used, combining aerobic and anaerobic reaction principles, to test the biodegradability of leachates. Leachates are tested for temperature, pH-value, redox potentials, and oxygen concentration. Chemical oxygen demand (COD) values are determined. Within 8 h, the biodegradation rates for both kinds of leachates are more than 90%. Due to the high organic content of Chinese waste, the degradation rate for Guilin MSW leachate is even higher, up to 97%. The effluent from SBR technique is suitable for direct discharge into bodies of water.

Effects of extra-cellular polymeric substances on organic pollutants biodegradation kinetics for A-step of adsorption-biodegradation process

The features of organic pollutants degradation mainly characterized by bio-flocculation for step-A of adsorption-biodegredation（AB） process were studied. By investigating the relationship of extracellular polymeric substances（EPS） with bioflocculation and introducing kinetic model of organic pollutant degradation into EPS, the kinetic model of organic pollutant degradation for step-A hioflocculation was deducted. And through the experiments, the kinetic constants were calculated as follows： k1 =0. 005 3; kc1 =1 710.7 and vmax1=10 min^-1.