ARTP-ALE Optimized Selection of Low Acetaldehyde Producing Brewer's Yeast and Fermentation Validation

Higher levels of acetaldehyde in beer are one of the major concerns in the current beer industry.Yeast produces acetaldehyde during alcoholic fermentation,and its modification significantly affects beer flavor and quality.A different mutant strain with lower acetaldehyde production and improved ethanol tolerance was constructed using the ARTP-ALE mutagenesis strategy with 4-methylpyrazole-disulfiram.As a result of the mutation,the alcohol dehydrogenase activity of the mutant strain decreased to about 71.22%of that of the wild-type strain.At the same time,the fermentation properties and genetic stability of the newly screened strain showed slight differences from the wild-type strain,and there were no safety concerns regarding industrial use of the mutant strain.

Health Risk Assessment of Employees Exposed to Chlorination By-products of Recreational Water in Large Amusement Parks in Shanghai

Objective Chlorination is often used to disinfect recreational water in large amusement parks;however,the health hazards of chlorination disinfection by-products(DBPs)to occupational populations are unknown.This study aimed to assess the exposure status of chlorinated DBPs in recreational water and the health risks to employees of large amusement parks.Methods Exposure parameters of employees of three large amusement parks in Shanghai were investigated using a questionnaire.Seven typical chlorinated DBPs in recreational water and spray samples were quantified by gas chromatography,and the health risks to amusement park employees exposed to chlorinated DBPs were evaluated according to the WHO's risk assessment framework.Results Trichloroacetic acid,dibromochloromethane,bromodichloromethane,and dichloroacetic acid were detected predominantly in recreational water.The carcinogenic and non-carcinogenic risks of the five DBPs did not exceed the risk thresholds.In addition,the carcinogenic and non-carcinogenic risks of mixed exposure to DBPs were within the acceptable risk limits.Conclusion Typical DBPs were widely detected in recreational water collected from three large amusement parks in Shanghai;however,the health risks of DBPs and their mixtures were within acceptable limits.

Progress in Analytical Methods of Halogenated Disinfection By-Products

Ensuring the health and safety of drinking water is crucial for both nations and their citizens.Since the 20th century,the disinfection of drinking water,effectively controlling pathogens in water sources,has become one of the significant advances in public health.However,the disinfectants used in the process,such as chlorine and chlorine dioxide,react with natural organic matter in the water to produce disinfection by-products(DBPs).Most of these DBPs contain chlorine,and if the source water contains bromine or iodine,brominated or iodinated DBPs,collectively referred to as Halogenated disinfection byproducts(X-DBPs),are formed.Numerous studies have found that X-DBPs pose potential risks to human health and the environment,leading to widespread concern.Mass spectrometry has become an important means of discovering new types of X-DBPs.This paper focuses on the study of methods for analyzing X-DBPs in drinking water using mass spectrometry.

Preparations of TiO_2 film coated on foam nickel substrate by sol-gel processes and its photocatalytic activity for degradation of acetaldehyde

Anatase TiO2 films were successfully prepared on foam nickel substrates by sol-gel technique using tetrabutyl titanate as precursor. The characteristics of the TiO2 films were investigated by XPS, XRD, FE-SEM, TEM and UV-Vis absorption spectra. The photocatalytic activities of TiO2 films were investigated by photocatalytic degradation reactions of gaseous acetaldehyde, an indoor pollutant, under ultraviolet light irradiation. It was found that Ni^2＋ doping into TiO2 films due to the foam nickel substrates resulted in the extension of absorption edges of TiO2 films from UV region to visible light region. The pre-heating for foam nickel substrates resulted in the formation of NiO layer, which prevented effectively the injection of photogenerated electrons from TiO2 films to metal nickel. The TiO2 films displayed high photocatalytic activity for the degradation of acetaldehyde, and were enhanced by calcining the substrates and coating TiO2 films repeatedly. The high activity was mainly attributed to the improvement of the characteristics of substrate surface and the increase of active sites on photocatalyst.

Stabilizing copper species using zeolite for ethanol catalytic dehydrogenation to acetaldehyde

The selective dehydrogenation of ethanol to acetaldehyde is a promising route for acetaldehyde production.Although Cu-based catalysts exhibit high activity in ethanol dehydrogenation,a rapid deactivation due to Cu sintering always occurs.In this study,highly dispersed Cu species were stabilized using the silanol defects in Beta zeolite(denoted as Beta)resulting from dealumination,and applied as robust catalysts for ethanol-to-acetaldehyde conversion.Typically,a long catalyst lifetime of 100 h with an acetaldehyde yield of^70%could be achieved over 5%Cu/Beta.The presence of Cu^+and Cu0 species and the agglomeration of Cu particles after a long-term reaction for 180 h were revealed by transmission electron microscopy,thermogravimetric analysis,and CO-diffuse-reflectance infrared Fourier transform spectroscopy,and were responsible for the deactivation of the Cu/Beta catalyst in the ethanol-to-acetaldehyde conversion.

Modification of Surface Reactivity by CO： Effects on Decomposition and Polymerization of Acetaldehyde on Ru（0001）

The adsorption and reaction of acetaldehyde on the clean and CO pre-covered Ru（0001） surfaces have been investigated using temperature programmed desorption method. On the clean Ru（0001） surface, the decomposition of acetaldehyde is the main reaction channel, with little polymerization occurring. However, on the CO pre-covered Ru（0001） surface, the de- composition of acetaldehyde is inhibited considerably with increasing CO coverage. Whereas, the polymerization occurs efficiently, especially at high CO coverage （θco〉0.5 ML）, which is strongly CO coverage dependent. Combined with previous studies, the well-ordered hexagohal structure of CO layer formed on the Ru（0001） surface at high CO coverage that matches the configuration of paraldehyde is likely to be the origin of this remarkable phenomenon.

Peracetic Acid Synthesis by Acetaldehyde Liquid Phase Oxidation in Trickle Bed Reactor

In this paper,shorter residence time（a few minutes）with high yield in the trickle bed process for per- acetic acid synthesis by acetaldehyde liquid phase oxidation can be realized on the selected packing material SA-5118.For acetaldehyde in acetone with ferric ion as catalyst,the optimized process conditions were presented. The main factors influencing the yield,selectivity and conversion are residence time,temperature and acetaldehyde concentration,respectively.The temperature range checked is from 30 to 65℃.High yield of 81.53%with high se- lectivity of 91.84%can be obtained at higher temperature of 55℃when the residence time is 5.5min and the acet- aldehyde concentration is 9.85%（by mass）.And there is a critical acetaldehyde concentration point（Cccp）between 18%and 19.5%（by mass）.At temperature less than 55℃,the highest yield to peracetic acid at each temperature level increases with temperature when the acetaldehyde concentration is below Cccp and decreases with temperature when the acetaldehyde concentration is above Cccp.

Pervaporation of Aqueous Solution of Acetaldehyde Through ZSM-5 Filled PDMS Composite Membrane

Hydrophobic ZSM-5 zeolite filled polydimethylsiloxane （PDMS） composite membranes with Nylon micro-filtration membrane as the support layer were prepared to separate acetaldehyde from its aqueous solution. The composite membranes were characterized by Fourier transform infrared spectroscopy and X-ray diffraction. Their structural morphology and thermal stability were also examined. The swelling study showed that the composite membranes presented higher degree of swelling in aqueous solution of acetaldehyde than in pure water at 25℃,

Smog Chamber Study on the Ozone Formation Potential of Acetaldehyde

Acetaldehyde is one of the important VOC species of O_(3)precursors in the atmospheric environment.The influences of relative humidity(RH)and initial VOC/NOx ratio(R_(CN))on the formation of O_(3)are studied in smog chamber experiments,and the MCM v3.3.1 mechanism of acetaldehyde is modified based on the experimental results.In low-RH conditions(RH=11.6%±1.1%),the O_(3)concentration at 6 h increases first and then decreases with the increase of R_(CN),and the R_(CN)at the inflection point of O_(3)concentrations is 3.2.In high-RH experiments(RH=78.8%±1.0%),variation of the O_(3)concentration at 6 h with R_(CN)is similar to that in low-RH experiments,but the R_(CN)at the inflection point is 2.8.RH has no significant effect on the O_(3)concentrations under low R_(CN)(<3),whereas it has a negative effect under high R_(CN)(>3).Compared with the experimental results,original MCM v3.3.1 greatly underestimates the O_(3)concentrations.Addition of both the photolysis process of peroxyacetyl nitrate and the photolysis process of HNO_(3)on the reactor surface into the original MCM can reduce the difference between the simulated O_(3)concentrations and the experimental results at 6 h from 24%−35%and 17%−49%to 6%−26%and 10%−42%under low-and high-RH conditions,respectively.The maximum incremental reactivity(MIR)of acetaldehyde simulated with the modified MCM is 4.0 ppb ppb−1 without considering the effect of other VOCs.

High-efficiency acetaldehyde removal during solid-state polycondensation of poly(ethylene terephthalate) assisted by supercritical carbon dioxide

The concentration of acetaldehyde(AA) is the main quality index of poly(ethylene terephthalate)(PET) used in food and drink packaging.A new method for AA removal has been developed by using supercritical carbon dioxide(sc CO2) during the solid-state polycondensation of PET.The influence factors of AA removal including the temperature,pressure,reaction time and the size of pre-polymer particles are systematically studied in this work.The results indicate that it is a highly efficient way to obtain high molecular weight PET with relative low concentration of AA.Correspondingly,the polymerization degree of PET could increase from 27.9 to 85.6 while the concentration of AA reduces from 0.229 × 10^(-6) to 0.055 × 10^(-6) under the optimal operation conditions of 230 °C,8 MPa and size of 0.30–0.45 mm.Thermodynamic performance tests show the increasing extent of PET crystallinity due to the fact that the plasticization of sc CO_2 is not obvious with extended reaction time,therefore the increasing crystallinity has no significant influence on AA removal.SEM observations reveal that the effects of sc CO_(2-) induced plasticization and swelling on PET increase significantly with the decrease of prepolymer size,and the surface of PET becomes more loose and porous in favor of the AA removal.

Simultaneous removal of ethanol, acetaldehyde and nitrogen oxides over V-Pd/γ-Al_2O_3-TiO_2 catalyst

V-Pd/γ-Al2O3-TiO2 catalysts with different vanadium contents were prepared by a combined sol-gel and impregnation method. X-ray diffraction （XRD）, N2 adsorption-desorption （BET）, X-ray photoelectron spectroscopy （XPS） and catalytic removal of ethanol, acetaldehyde and nitrogen oxides at low temperature （〈300 ？C） were used to assess the properties of the catalysts. The results showed that the sample with 1wt% vanadium exhibited an excellent catalytic performance for simultaneous removal of ethanol, acetaldehyde and nitrogen oxides. The conversions of ethanol, acetaldehyde and nitrogen oxides at 250 ？C were 100%, 74.4% and 98.7%, respectively. V-Pd/γ-Al2O3-TiO2 catalyst with 1 wt% vanadium showed the largest surface area and higher dispersion of vanadium oxide on the catalyst surface, and possessed a larger mole fraction of V4＋ species and unique PdO species on the surface, which can be attributed to the strong synergistic effect among palladium, vanadium and the carriers. The higher activity of V-Pd/γ-Al2O3-TiO2 catalyst is related to the V4＋ and Pd2＋ species on the surface, which might be favorable for the formation of active sites.

Ion-Velocity Map Imaging Study of Photodissociation Dynamics of Acetaldehyde

The photodissociation dynamics of acetaldehyde in the radical channel CH3＋HCO has been reinvestigated using time-sliced velocity map imaging technique in the photolysis wavelength range of 275-321 nm. The CH3 fragments have been probed via （2＋1） resonance-enhanced multiphoton ionization. Images are measured for CH3 formed in the ground and excited states （v2=0 and 1） of the umbrella vibrational mode. For acetaldehyde dissociation on T1 state after intersystem crossing from S1 state, the products are formed with high translational energy release and low internal excitation. The rotational and vibrational energy of both fragments increases with increasing photodissociation energy. The triplet barrier height is estimated at 3.8814-0.006 eV above the ground state of acetaldehyde.

Role of Reduced Defects for Coupling Reactions of Acetaldehyde on Anatase TiO2（001）-（1×4） Surface

The chemistry of acetaldehyde (CH3CHO) adsorbed on the anatase TiO2(001)-(1×4) surface has been investigated by temperature-programmed desorption (TPD) method. Our experimental results provide the direct evidence that the perfect lattice sites on the anatase TiO2(001)-(1×4) surface are quite inert for the reaction of CH3CHO, but the reduced defect sites on the surface are active for the thermally driven reductive carbon-carbon coupling reactions of CH3CHO to produce 2-butanone and butene. We propose that the coupling reactions of CH3CHO on the anatase TiO2(001)-(1×4) surface should undergo through the adsorption of paired CH3CHO molecules at the reduced defect sites, since the existing reduced Ti pairs provide the suitable adsorption sites.

Phylogenetically diverse,acetaldehyde-degrading bacterial community in the deep sea water of the West Pacific Ocean

As a major aldehyde pollutant widely existing in industry and our daily life, acetaldehyde is more and more harmful to human health. As characteristic habitat niche, bacteria from deep sea environments are abundant and distinctive in heredity, physiology and ecological functions. Thus, the development of acetaldehyde-degrading bacteria from deep sea provides a new method to harness acetaldehyde pollutant. Firstly, in this study,acetaldehyde-degrading bacteria in the deep sea water of the West Pacific Ocean were enriched in situ and in the laboratory respectively, and then the diversity of uncultured bacteria was studied by using 16 S r RNA genes. Then acetaldehyde-degrading strains were isolated from two samples, including enrichment in situ and enrichment in laboratory samples of deep sea water from the West Pacific Ocean using acetaldehyde as the sole carbon source,and then the ability of acetaldehyde degradation was detected. Our results showed that the main uncultured bacteria of two samples with different enrichment approaches were similar, including Proteobacteria,Actinobacteria, Firmicutes, Cyanobacteria, but the structure of bacterial community were significant different.Four subgroups, α, γ, δ and ε, were found in Proteobacteria group. The γ-Proteobacteria was dominant（63.5%clones in laboratory enriched sample, 75% clones in situ enriched sample）. The species belonged to γ-Proteobacteria and their proportion was nearly identical between the two enrichment samples, and Vibrio was the predominant genus（45% in laboratory enriched sample, 48.5% in situ enriched sample）, followed by Halomonas（9% in situ enriched sample） and Streptococcus（6% in laboratory enriched sample）. A total of 12 acetaldehyde-degrading strains were isolated from the two samples, which belonged to Vibrio, Halomonas,Pseudoalteromonas, Pseudomonas and Bacillus of γ-Proteobacteria. Strains ACH-L-5, ACH-L-8 and ACH-S-12,belonging to Vibrio and Halomonas, have strong ability of acetaldehyde degradation, which could tolerate 1.5 g/L acetaldehyde and degrade 350 mg/L acetaldehyde within 24 hours. Our results indicated that bacteria of γ-Proteobacteria may play an important role in carbon cycle of deep sea environments, especial the bacteria belonging to Vibrio and Halomonas and these strains was suggested for their potentials in government of aldehyde pollutants.

Age-related Metabolic Effects of Acetaldehyde on Rats With Reference to Detoxification Enzymes and Sulfhydryl Groups

Induced-acetaldehyde toxic effects on gluatathione [GSH] metabolism and sulfhydryl (SH) groups in liver and in brain of female albino rats with reference to age was studied.The total -SH groups were decreased whereas the specific activities of glutathione-S-transferase [GST] and glutathione peroxidase [GP0] were increased in acetaldehyde treated rats. However, the specific activity levels of glutathione reductase [GR] and Γ-glutamylcysteine synthetase [Γ-GCS] were decreased. In general, acetaldehyde indueed changes in the specific activities of the enzymes that increase with increasing age

Effect of Acetaldehyde on Oxidoreductases in Tissues of Rats at Different Ages

The toxicity of acetaldehyde and age related changes on oxidoreductases in the liver,brain, kidney, and musele of female albino rats (Wistar strain) were studied. The specific activities of lactate [LDH], isocitrate [ICDH (NAD/NADP)], succinate [SDH], malate [MDH], glutamate [GDH] and glucose-6-Phosphate [G-6-PDH] dehydrogenases were signifieantly inereased as a function of age. However, acetaldehyde treatment significantly inhibited oxidoreductases in the tissues of 21, 90 and 180 day old rats. Liver enzymes of young (21 days) rats exhibited greater sensitivity to acetaldehyde toxicity. Similar inhibition of oxidoreductases in brain and kidney of adult (180 days) rats treated with acetaldehyde was observed. LDH and GDH as compared to other enzymes studied showed higher susceptibility to acetaldehyde toxicity. The differential sensitivity of tissues and inhibition of oxidoreductases by acetaldehyde as a function of age could be attributed to hypoxic conditions, energy crisis, and mitochondrial structural changes. The results suggest that acetaldehyde affects oxidation of glucose via HMP shuni pathway, glycolytic pathway and Krebs cycle resulting in the impairment of carbohydrate metabolism

基于by-production技术的中国绿色发展效率测度及差异化研究

在资源环境约束日益严峻的背景下,如何推动绿色发展,促进人与自然和谐共生成为中国发展道路上的关键问题。通过对中国绿色发展效率进行测度和差异化研究,能更好地把握中国绿色发展现状,进而加快实现经济可持续发展。首先,以中国30个省份为研究对象,引入了DEA框架下by-production技术测度中国绿色发展效率,该技术考虑了非期望产出只由能源投入产得的特征,更加符合实际生产过程。其次,采用Dagum基尼系数进一步探究中国绿色发展效率空间差异及其来源。通过研究发现:样本考察期内,基于by-production技术的中国绿色发展效率整体较高,绿色发展效率均值为0.84,但仍有提升空间;绿色发展效率的地区差距显著,且呈上升趋势。其中,区域间差距是最主要来源,平均贡献率为44.12%;西部地区区域内绿色发展效率差异最大;东部地区和东北地区区域间差异最大。因此,要加强区域间绿色发展交流合作,实现区域绿色协同发展。最后,针对所得结论提出了对策建议,为经济社会发展全面绿色转型提供决策参考,有助于推动实现经济效益与环境效益相统一。

臭氧化法制备N-Boc-(甲氨基)乙醛

以N-甲基烯丙胺和二碳酸二叔丁酯为原料,在乙醇中缩合得到N-Boc-甲基烯丙胺,再以乙酸乙酯为溶剂经臭氧臭氧化,用NaHSO_(3)还原分解,经萃取、蒸馏,制备N-Boc-(甲氨基)乙醛。采用L16(45)正交实验确定了最优臭氧化温度为5~10℃、反应时间为3 h、臭氧流量为0.04 m^(3)/h,粗产物用乙醚萃取,获得目标产物收率78.7%,纯度99.2%(HPLC),并用IR、^(1)H NMR、^(13)C NMR和MS表征了产物的结构。

Recycling of Local Qatar’s Steel Slag and Gravel Deposits in Road Construction

Every year,the State of Qatar generates about 400,000 tons of steel slag and another 500,000 tons of gravel as a result of steel manufacturing and washing sand,respectively.The two materials(by-products)are not fully utilized to their best market values.At the same time,infrastructural renewal will take place in Qatar over the next ten years,and there will be a greater demand for aggregates and other construction materials as the country suffers from the availability of good aggregates.This paper presents results obtained on the use of steel slag,gravel and gabbro(control)in HMAC(hot mix asphalt concrete)paving mixtures and road bases and sub-bases.Tests were conducted in accordance with QCS-2010(Qatar Construction Specifications)and results were compared with QCS requirements for aggregates used in these applications.Based on the data obtained in this work,steel slag and gravel aggregates have a promising potential to be used in HMAC paving mixtures on Qatar’s roads,whether in asphalt base and asphalt wearing courses or as unbound aggregates in the base and sub-base pavement structure.

酱香型白酒轮次酒的醛类物质与对应出窖糟醅的理化指标相关性研究

乙醛、乙缩醛和糠醛含量对酱香型白酒的风味有一定影响。该研究通过主成分分析(PCA)、偏最小二乘判别分析(PLS-DA)和皮尔逊(Pearson)相关性分析对1~7轮次酱香型白酒样的醛类物质含量和对应出窖糟醅的理化指标进行了分析。结果表明,乙醛和乙缩醛含量1~4轮次酒增加,5轮次酒降低,5~7轮次酒增加,7轮次酒达到最高,分别为487.12 mg/L、360.94 mg/L;糠醛含量随着轮次增加而增加,7轮次酒达到最高,为623.63 mg/L。出窖糟醅的水分、糖分含量和酸度随着轮次增加均为先升高后降低,淀粉含量随着轮次增加而降低。1~3轮次酒的醛类物质及出窖糟醅理化指标与4~7轮次存在较大差异。乙醛、乙缩醛和糠醛与淀粉含量呈极显著负相关(P<0.01),与糖分、酸度、水分呈极显著正相关(P<0.01)。在生产过程中需要严格控制这些指标,以确保基酒的质量和稳定性。