莠去津降解菌HB-5的最佳产酶培养基及发酵条件

从农药厂废水中分离到一株降解莠去滓的节杆菌(Arthrobacter sp.)HB-5,以从该菌中提取到的降解酶对莠去津的降解率为指标,进行最佳产酶培养基及发酵条件的优化研究,对其产酶量进行了评价.通过正交试验和均匀试验,对细菌HB-5的发酵培养基进行了优化研究.运用SAS软件进行结果分析,所获优化培养基配方为:蔗糖3.0g·L-1,莠去津0.38g·L-1,K2HPO40.5g·L-1,KH2PO41.2 g·L-1,MgSO4·7H2O 1.2g·L-1,NaCl 0.1g·L-1,微量元素溶液3.8mL·L-1.得到菌株培养的最佳优化条件为:菌株发酵液培养时间为48h.接种量为2%,发酵液初始pH值为9,250mL三角瓶中装液量为80mL经优化后,降解酶对莠去津的降解率(91.64%)比原培养基(40.67%)提高了125%.     

1株巨大芽孢杆菌特性、解磷条件研究及其应用初探

白酒废水污泥资源化处理是白酒行业可持续发展面临的难题,活性污泥中可溶性磷的提升可增加活性污泥应用于复合肥生产的价值。文章以从白酒废水处理系统的活性污泥中分离的巨大芽孢杆菌为研究对象,对其生长特性和解磷条件进行研究和优化,并将该菌株用于白酒废水的活性污泥进行解磷作用。实验结果表明,该巨大芽孢杆菌对有机磷和无机磷都具有显著解离作用,可将难溶性磷素降解为可溶性的磷素,在有机磷培养基中可溶性磷素增加量为1.75 mg/L,无机磷培养基中可溶性磷素增加量为22.8 mg/L,且解磷速率大致与菌体数量呈正相关;单因素试验和正交表明,该巨大芽孢杆菌的最佳培养基组合为玉米粉0.5%,豆粕0.025%,七水硫酸亚铁0.003%;最适解磷条件为pH 7.5,培养32℃,接种量3%,装液量为50 mL/250 mL,在此条件下,可溶性磷素增加量达到(33.72±0.08) mg/L;以高粱秸秆为膨胀剂,以活性污泥为基质,该巨大芽孢杆菌能将白酒废水活性污泥中的不溶性磷进行解离,固态发酵解磷效果优于液态发酵,发酵后活性污泥可溶性磷素可增加到11.50 mg/kg,提高38.69%。巨大芽孢杆菌提升白酒废水污泥中可溶性磷素,为该菌对于污泥堆肥应用提供前期研究基础和数据支持。     

2株降解菲的植物内生细菌筛选及其降解特性

为了获得具有菲降解特性的植物内生细菌,通过选择性富集培养,本研究从多环芳烃污染区植物体内分离得到2株能够降解液体培养基中高浓度菲(200 mg·L-1)的植物内生细菌(菌株P1和P3).经形态观察、生理生化特征鉴定和16S rDNA序列同源性分析,分别将菌株P1和P3鉴定为寡养单胞菌属(Stenotrophomonas sp.)和假单胞菌属(Pseudomonas sp.)的细菌.菌株P1和P3均为好氧生长,28℃、150 r·min-1摇床培养7 d,2株菌对无机盐培养基中菲(100 mg·L-1)的降解率均高于90%.条件实验表明,温度20～30℃,pH 6.0～8.0,盐含量0%～4%,装液量10～30 mL(100 mL三角瓶)2菌株生长良好且对菲降解率高于70%.其最适生长和降解温度为30℃,pH为7.0,盐含量≤4%,装液量≤30 mL.综合比较2株菌对菲的降解特性,P1菌株高温耐受性稍强,而P3菌株对环境pH改变和缺氧的耐受性稍强.     

PVA固定化Corynebacterium sp.JY03降解苯酚的特性研究

以PVA(聚乙烯醇)作为载体将降酚菌株Corynebacterium sp.JY03进行固定化包埋处理,正交试验确定该菌株固定化细胞制备的条件,然后对固定化细胞的降酚性能进行研究。试验确定最佳固定条件为:PVA质量分数为6%,菌液量/PVA水溶液体积比为6/30,氯化钙含量为2.0%,钙化交联时间为8 h;固定化细胞降解苯酚的最适温度为30~35℃,最适pH值为6.5~7.5,在初始苯酚浓度为700 mg/L,装液量50 mL,培养42 h后,苯酚降解率达99.1%。固定化细胞重复利用6次苯酚降解率仍高于85.2%,其性能优于游离细胞,这将为该菌株进一步应用于含酚废水的生物处理提供实践条件。     

己烯雌酚降解菌株沙雷氏菌的分离鉴定及其降解特性

利用具有降解己烯雌酚(diethylstilbestrol,DES)特性的功能微生物来降解DES、有望实现环境中DES的有效去除,然而迄今关于降解DES的功能菌株及其降解特性的报道很少.本研究通过选择性富集培养,从某污水处理站活性污泥中分离获得1株具有DES降解特性的细菌(菌株S).经形态观察、生理生化试验及16S rDNA序列同源性分析将菌株S鉴定为沙雷氏菌属(Serratia sp.)细菌.菌株S好氧生长,30℃、150 r·min-1摇床培养7 d后,对无机盐培养基中DES(50 mg·L-1)的降解率达68.3%.通过摇瓶实验,优化了菌株S生长和降解DES的最适环境条件:温度30℃,底物浓度40～60 mg·L-1,pH 7.0,接种量5%,盐添加量0 g·L-1,装液量10 mL(100 mL三角瓶).     

一株造纸废水降解菌的分离、鉴定及特性研究

将不同稀释倍数的造纸废水接种在细菌培养基上,培养2 d后采用划线法分离,然后采用琼脂块培养法,把每一个长满单菌落的琼脂块分别接种到选择培养基中,选取COD降解能力最大的作为目标菌株,最后从造纸废水初始浓度、温度、pH值、接种量、降解时间等方面讨论了该菌株对造纸综合废水的降解特性。结果表明:所筛得的目标降解菌ZH3菌体直径为(0.6～0.8)μm×(1.4～2.4)μm,杆状,有数根鞭毛,无芽孢,为革兰氏阴性菌,初步鉴定该菌属产碱假单胞菌,该菌降解造纸综合废水的适宜条件为废水初始COD浓度为500 mg/L,温度为30～35℃,pH为7.0,接种量为10%,降解时间为48 h。     

非均相催化降解去除废水中过氧化氢异丙苯

为消除废水中CHP(过氧化氢异丙苯)对废水生物处理系统的不利影响,筛选出MnO₂为适合催化CHP降解脱毒的非均相催化剂,并以MnO₂为催化剂,催化降解自配废水中的CHP,采用间歇试验考察了反应pH、温度、MnO₂投加量、初始ρ(CHP)对CHP去除效果的影响,对CHP降解动力学进行了分析,同时对处理前后废水组分和生物毒性做了鉴定.结果表明:CHP催化降解速率与温度、初始ρ(CHP)和ρ(MnO₂)呈正相关;pH为4～10,温度为50～70 ℃,ρ(MnO₂)为10～20 g/L是较为优化的反应条件.MnO₂催化降解CHP的反应符合表面反应机制,催化剂表面接触面积越大,CHP降解速率越快;在pH为2或3时,CHP降解速率显著高于pH为4～10时,但Mn溶出较为显著.在初始ρ(CHP)为0.4～1.0 g/L时,CHP催化降解反应遵循一级反应动力学,符合Arrhenius方程,E_a(表观活化能)为37.56 kJ/mol.反应产物主要为2-苯基-2-丙醇,处理后废水的OUR(耗氧速率)抑制率由63%降为0,对活性污泥没有抑制.      

除臭酵母JZ-6发酵条件的研究

为给除臭酵母JZ-6的工业化生产提供参考依据,通过单因素试验和正交试验,以酵母JZ-6对恶臭中主要臭气物质氨气的去除率为指标进行试验。确定了除臭酵母JZ-6的优化发酵条件为:接种量为8%,培养基起始pH为4,500mL瓶中装液量为150 mL,发酵温度为30℃,培养时间为24 h,在此发酵条件下,该菌株对氨的去除率达88.6%。     

偏肿拟栓菌共代谢降解芘条件的优化

为提高中国东北土著白腐真菌偏肿拟栓菌(Pseudotrametes gibbosa)对高分子量多环芳烃芘的共代谢降解效果,通过正交试验研究了共代谢基质、接种量、装液量及2,2￠-连氮-二(3-乙基苯并噻唑-6-磺酸)(ABTS)的最佳配比,同时采用浓度梯度法考察芘的初始浓度对偏肿拟栓菌共代谢降解芘的影响.结果表明,偏肿拟栓菌Pseudotrametes gibbosa共代谢降解芘的最佳培养基为:麸皮浓度为20g/L,接种量为3片直径为10mm的菌片,装液量为50mL,不加ABTS,在该培养条件下,酶活可达53.41U/mL,对芘的降解率达到88.8%.初始浓度小于10mg/L的芘对菌体产酶有一定的促进作用,大于10mg/L时抑制漆酶的分泌,同时菌体对初始浓度小于90mg/L芘的降解率在22.24%~93.54%之间.     

高效复合降解工程菌处理抗生素废水的研究

本文采用固体发酵培养研制的高效复合菌处理生物制药抗生素废水 ,通过降解温度、pH值、菌剂用量等进行了一系列试验。试验结果表明 ,在选定的条件下活菌数可达到 9× 1 0 8个 /g。在治理抗生素废水研究中取得了最优工艺条件 ,为废水治理工业化提供了有价值的参数。     

Trisomic pregnancies have normal human chorionic gonadotropin bioactivity

Sera from women carrying either chromosomally normal or aneuploid fetuses in the first half of pregnancy were assayed for human chorionic gonadotropin (hCG) bioactivity in order to determine whether differences might provide the basis for a useful antenatal screen for aneuploidy. A mouse uterine weight assay was used to assess hCG bioactivity in sera from 35 patients undergoing chorionic villus sampling (12 normal pregnancies and 23 trisomic pregnancies) and in sera from 18 patients undergoing elective second-trimester abortion (12 presumed normal pregnancies, 3 trisomic pregnancies, and 3 pregnancies with neural tube defects). The hCG bioactivity to immunoactivity (B:I) ratio of normal pregnancies progressively decreased from 7.7±1.3 at 4–5 menstrual weeks, to 4.7±0.4 at 9–12 menstrual weeks, to 3.3±0.5 at 16–20 menstrual weeks. There were no significant differences in the B:I ratios between normal and aneuploid pregnancies in either the first-trimester (4.7±0.4 versus 5.2±0.3) or the second-trimester samples (3.3±0.5 versus 2.6±0.3), despite significantly greater hCG concentrations in the trisomic pregnancies. We conclude that while aneuploid pregnancies display dysfunctional regulation of hCG expression, the bioactivity of their hCG is normal and does not appear to form the basis for a useful screen for aneuploidy.     

回转窑热解气化炉处理生活垃圾特性

基于目前固定床热解气化法在常温下进行存在燃气热值和气化效率较低、燃料适用范围小和预处理复杂等问题,采用控制变量法设计探究了不同预热空气温度和过量空气系数对小型回转窑式热解气化炉处理村镇生活垃圾的影响.结果表明:预热空气温度升高有利于垃圾热解气化产气,但有一定的局限性,当温度超过600 ℃时垃圾的气化产气明显下降;当过量空气系数为0.4时,垃圾的热解气化效率达到最大值,并且焦油产量最小.垃圾原样在过量空气系数为0.4、空气预热温度为500 ℃下对底渣、飞灰进行重金属含量的分析测试结果显示,飞灰中的铅含量远高于GB 18598—2001《危险废物填埋污染控制标准》相关标准限值,需要经过处理才能排放,二英采样分析结果显示其含量均低于GB 18485—2014《生活垃圾焚烧污染控制标准》限值.研究显示,该回转窑式热解气化工艺处理生活垃圾的最佳过量空气系数为0.4,最佳空气预热温度为500 ℃,在此最佳工况条件下焦油产量小,飞灰及焦渣中重金属含量小,ρ(二英)低于0.10 ng/m3.      

磁芬顿处理酸性黑10B模拟废水的实验研究

研究不同磁化时间、磁场强度和催化氧化各种影响因素下芬顿试剂对酸性黑10B染料模拟废水的去除率。结果表明:对于100mL酸性黑10B染料模拟废水,在pH=3,FeSO4.7H2O=500mg,H2O2=0.4mL条件下,反应20min,COD去除率达90.3%。外加磁场磁场强度为427.8mT的作用下,磁化反应20min,COD的去除率提高了3.7%。     

Heterogeneous uptake of NO2 on soils under variable temperature and relative humidity conditions

Heterogeneous reactions of nitrogen dioxide (NO₂) on soils collected from Dalian (S1) and Changsha (S2) were investigated over the relative humidity (RH) range of 5%-80% and temperature range of 278-328 K using a horizontal coated-wall flow tube. The initial uptake coefficients of NO₂ on S2 exhibited a decreasing trend from (10 ± 1.3) × 10^-8 to (3.1 ± 0.5) × 10^-8 with the relative humidity increasing from 5% to 80%. In the temperature effect studies, the initial uptake coefficients of S1 and S2 decreased from (10 ± 1.2) × 10^-8 to (3.8 ± 0.5) × 10^-8 and from (16 ± 2.2) × 10^-8 to (3.8 ± 0.4) × 10^-8 when temperature increased from 278 to 288 K for S1 and from 278 to 308 K for S2, respectively. As the temperature continued to increase, the initial uptake coefficients of S1 and S2 returned to (7.9 ± 1.1) × 10^-8 and (20 ± 3.1) × 10^-8 at 313 and 328 K, respectively. This study shows that relative humidity could influence the uptake kinetics of NO₂ on soil and temperature would impact the heterogeneous chemistry of NO₂.     

A steam dried municipal solid waste gasification and melting process

Considering high-moisture municipal solid waste (MSW) of China, a steam dried MSW gasification and melting process was proposed, the feasibility was tested, and the mass and energy balance was analyzed. Preliminary experiments were conducted using a fixed-bed drying apparatus, a 200 kg per day fluidized-bed gasifier, and a swirl melting furnace. Moisture percentage was reduced from 50% to 20% roughly when MSW was dried by slightly superheated steam of 150°C–350°C within 40 min. When the temperature was less than 250°C, no incondensable gas was produced during the drying process. The gasifier ran at 550°C–700°Cwith an air equivalence ratio (ER) of 0.2–0.4. The temperature of the swirl melting furnace reached about 1240°C when the gasification ER was 0.3 and the total ER was 1.1. At these conditions, the fly ash concentration in the flue gas was 1.7 g·(Nm³)⁻¹, which meant over 95% fly ash was trapped in the furnace and discharged as slag. 85% of Ni and Cr were bound in the slag, as well as 60% of Cu. The mass and energy balance analysis indicates that the boiler heat efficiency of an industrial MSW incineration plant reaches 86.97% when MSW is dried by steam of 200°C. The boiler heat efficiency is sensitive to three important parameters, including the temperature of preheated MSW, the moisture percentage of dried MS Wand the fly ash percentage in the total ash.     

抗坏血酸与柠檬酸对尾矿Pb污染土壤电动修复的强化效果

为研究抗坏血酸与柠檬酸作为增强试剂对高酸性缓冲能力的尾矿Pb污染土壤[w（Pb）为（5491.9±24）mg/kg]电动修复的强化效果,利用0.1 mol/L柠檬酸作为阴极电解液并控制阴极pH在2~3之间,系统分析土壤饱和液中c（抗坏血酸）（0~0.4 mol/L）、修复电压梯度（1~3 V/cm）对电动修复Pb污染土壤的影响,并对土壤中Pb的存在形态进行分析.结果表明:当电动修复过程中施加电压梯度为1 V/cm、c（抗坏血酸）（0~0.4 mol/L）作为饱和液时,随着c（抗坏血酸）的增加,土壤中Pb的迁移能力随之增加,Pb的去除率得到提高.当c（抗坏血酸）达到0.4 mol/L时,土壤中Pb的去除率为36.86%;保持c（抗坏血酸）为0.4 mol/L,当施加电压梯度由1 V/cm增至2 V/cm时,土壤中Pb的去除率得到增加（最高可达87.09%）,通过Pb的形态变化可知,w（弱酸提取态Pb）由初始的2.99%（1 V/cm）最大可降至0.34%（2 V/cm）,w（可还原态Pb）由初始的83.86%（1 V/cm）最大降至2.94%（2 V/cm）.研究显示,当c（抗坏血酸）为0.4 mol/L、柠檬酸（作为阴极电解液）控制阴极电解室pH在2~3之间、施加电压梯度为2 V/cm时,土壤中Pb的迁移能力显著提高并达到较好的修复效果.      

假单胞菌No.66降解氯乙酸的研究

本文介绍从水稻土分离得一株可利用单氯乙酸和二氯乙酸作唯一碳源的假单胞菌No.66。该菌在二氯乙酸或单氯乙酸基质上生长时,会释放氯离子,并能使二氯乙酸为碳源的基质之pH值由7降至5以下。No.66菌适宜生长的氯乙酸浓度为0.4—0.5％,适宜脱氯的pH为6.0。所产生的脱氯酶与碳源种类有关。粗脱氯酶液在4℃进行聚丙烯酰胺凝胶(10.5％)电泳呈现一条酶活力带,该酶不仅能使单氯乙酸和二氯乙酸脱氯,而且也能使三氯乙酸脱氯。     

有机负荷对SBAR中好氧颗粒污泥特性影响的研究

研究不同有机负荷条件下,气升式间歇反应器(SBAR)中培养好氧颗粒污泥,并观察其形态变化及处理模拟生活污水的效果。实验结果表明,在SBAR中,有机负荷为3kgCOD/(m3.d)和6 kgCOD/(m3.d)下均可以培养出成熟的好氧颗粒污泥,SVI值分别为25mL/g和32mL/g,沉降速度分别达到33.85m/h和33m/h。但较高的有机负荷条件下,培养出的污泥颗粒的粒径大多数在0.6mm～1.5mm,且COD、氨氮和总磷的去除率分别可达97.57%、87.74%和86.60%;较低有机负荷条件下形成的污泥颗粒粒径多数在0.4mm～1.0mm之间,COD、氨氮和总磷的去除率分别为96.93%、85.48%和84.20%。     

Persistence of Human Noroviruses on Food Preparation Surfaces and Human Hands

The human noroviruses (NoV) are the major cause of acute non-bacterial gastroenteritis and are commonly transmitted by foodborne routes. Epidemiological evidence from propagated outbreaks, as well as environmental sampling, suggest that these viruses are environmentally stable. The purpose of this study was to examine the persistence of representative human NoV on the fingertips of volunteers and on commonly used food preparation surfaces. Human fingerpads and surfaces (stainless steel, Formica^®, and ceramic) were inoculated with 20% fecal suspensions of Norwalk virus (NV) or Snow Mountain virus (SMV). The virus inocula were recovered by elution at serial time points ranging from 0 to 120 min post-inoculation (for fingerpads) and after up to 42 days (for surfaces). The quantity of detectable viral RNA, expressed as genome equivalent particles (GEP) was evaluated using quantitative real-time RT-PCR (RT-qPCR). The amount of NV RNA on the surface decreased gradually over time, with an average reduction ranging from 1.5 to 2.9 log₁₀ GEP after 21–28 days storage under ambient conditions. SMV showed greater environmental persistence, with a 0.4–1.2 log₁₀ GEP reduction on all three surfaces after 42 days of ambient storage. On fingerpads, the amount of human NoV RNA declined slightly (<0.25 log₁₀) after 15 min and remained relatively unchanged thereafter (through 120 min). These results support the epidemiological evidence that food preparation surfaces and human hands can act as vehicles for human NoV transmission long after the initial contamination event has occurred.     

Groundwater-dependent irrigation costs and benefits for adaptation to global change

The effects of a 1.5 °C global change on irrigation costs and carbon emissions in a groundwater-dependent irrigation system were assessed in the northwestern region of Bangladesh and examined at the global scale to determine possible global impacts and propose necessary adaptation measures. Downscaled climate projections were obtained from an ensemble of eight general circulation models (GCMs) for three representative concentration pathways (RCPs), RCP2.6, RCP4.5, and RCP8.5 and were used to generate the 1.5 °C warming scenarios. A water balance model was used to estimate irrigation demand, a support vector machine (SVM) model was used to simulate groundwater levels, an energy-use model was used to estimate carbon emissions from the irrigation pump, and a multiple linear regression (MLR) model was used to simulate the irrigation costs. The results showed that groundwater levels would likely drop by only 0.03 to 0.4 m under a 1.5 °C temperature increase, which would result in an increase in irrigation costs and carbon emissions ranging from 11.14 to 148.4 Bangladesh taka (BDT) and 0.3 to 4% CO₂ emissions/ha, respectively, in northwestern Bangladesh. The results indicate that the impacts of climate change on irrigation costs for groundwater-dependent irrigation would be negligible if warming is limited to 1.5 °C; however, increased emissions, up to 4%, from irrigation pumps can have a significant impact on the total emissions from agriculture. This study revealed that similar impacts from irrigation pumps worldwide would result in an increase in carbon emissions by 4.65 to 65.06 thousand tons, based only on emissions from groundwater-dependent rice fields. Restricting groundwater-based irrigation in regions where the groundwater is already vulnerable, improving irrigation efficiency by educating farmers and enhancing pump efficiency by following optimum pumping guidelines can mitigate the impacts of climate change on groundwater resources, increase farmers’ profits, and reduce carbon emissions in regions with groundwater-dependent irrigation.