不同降水下覆盖与缓释肥减量对油菜土壤微生物群落结构的影响

为探讨沟垄集雨、秸秆覆盖和减量缓释肥集成技术对油菜土壤微生物群落结构的影响,在大田定位试验条件下,设置3种栽培方式（秸秆覆盖、沟垄集雨、传统平作）和4种施肥水平（习惯施肥、缓释肥减量20%、缓释肥减量40%、不施肥）,比较分析2016~2017年（多雨年份）和2017~2018年（季节性干旱年份）这2种不同降水年型下油菜土壤微生物群落结构对集成技术的响应.结果表明,不同降雨条件下,秸秆覆盖+缓释肥减量20%（J80）与沟垄覆盖+缓释肥减量20%（M80）较习惯栽培（PC）更利于土壤微生物生长.在多雨年型和季节性干旱年型下,J80与M80能平均分别提高微生物量碳9.94%和10.32%;提高土壤微生物量氮2.38%和1.19%.多雨年型下,土壤微生物磷酸脂肪酸（PLFA）总量较干旱年型降低30.75%,覆盖能有效提高土壤PLFA质量摩尔浓度.多雨年型下土壤细菌、真菌PLFA质量摩尔浓度较干旱年型平均减少33.67%和53.21%;而放线菌PLFA增加13.04%.微生物群落对异常降水具有敏感响应.多雨气候会造成细菌/真菌升高;干旱气候则会增加直链饱和脂肪酸/直链单不饱和脂肪酸及直链单不饱和脂肪酸/环丙烷脂肪酸.通过秸秆覆盖与缓释肥的集成技术,能稳定异常降水下的土壤微环境,缓解水分和养分胁迫,为油菜稳产和可持续发展提供有效途径.     

Prenatal diagnosis of carnitine palmitoyltransferase 2 deficiency in chorionic villi: a novel approach

Carnitine palmitoyltransferase 2 (CPT2) deficiency, the most common autosomal recessive inherited disease of the mitochondrial long-chain fatty acid (LCFA) β-oxidation, may result in three distinct clinical phenotypes, namely, a mild adult muscular form, a severe infantile hepatocardiomuscular disease, and a neonatal form, which includes dysmorphic features in addition to hepatocardiomuscular symptoms. Both the latter forms are life-threatening diseases, and prenatal diagnosis (PND) can be offered to couples at a one-fourth risk of having an affected child. PND of CPT2 deficiency hitherto relied mostly on mutation detection from fresh chorionic villi (10 weeks' gestation), since CPT2 activity could be assayed on cultured amniocytes only (16–17 weeks' gestation). We devised a CPT2 activity assay from 10 mg of chorionic villi sampling (CVS). Combining this enzymatic assay to haplotype study using polymorphic markers linked to the CPT2 gene, we were able to carry out within 2 days, CPT2 deficiency PND, in two unrelated families, using a CVS performed at the 11th week of gestation. Copyright © 2003 John Wiley & Sons, Ltd.     

Analysis of TCDD and TCDF on the ppq-level in milk and food sources

Analysis of 2378-TCDD and 2378-TCDF on the ppq-level in foods with high fat content is described. The migration over twelve days of 2378-TCDD, 2378-TCDF and 1278-TCDF from bleached paperboard cartons into whole milk was found to be exponential with time. A survey of selected fatty foods shows the presence of 2378-TCDD and 2378-TCDF in foodstuff.     

废食用油脂作生物柴油原料的可行性分析

分析了各国废食用油脂的产生、回收和法规管理现状.重点通过分析废食用油脂物化性质,评价利用废食用油脂制造生物柴油的工艺特征和技术可行性.探讨了利用废食用油脂制造的生物柴油产品的品质和环境效益以及使用要求.同时分析了利用废食用油脂制造生物柴油的经济成本和存在的问题.     

Intrinsic degradation of volatile fatty acids in laboratory-compacted clayey soil

Volatile fatty acids (VFAs) represent the major organic constituent of landfill leachate and provide the greatest potential for leachate induced organic contamination of groundwater (e.g. as represented by an increase in the concentration of dissolved organic carbon and chemical oxygen demand). Long-term diffusion tests were performed for laboratory-compacted clayey soil plugs exposed to continuous supply of synthetic leachate containing VFAs. Significant microbial activity developed upon exposure of the soil's indigenous microorganisms to these degradable contaminants. The growth of heterotrophic aerobic bacteria (HAB, which include facultative anaerobes), sulfate reducing bacteria (SRB) and methanogenic bacteria carrying out fermentation and mineralization of the VFAs became evident after 30-50 days of testing. The maximum microbial counts of (2-8) x 10(8) and (0.1-1) x 10(8) cfu/g for HAB and SRB were localized in the soil layer at the interface with the source of organic and inorganic nutrients. Regardless of this rapid growth in microbial population, the VFA consumption was small and measurable only after a lag of 140-180 days. It is considered that this lag of otherwise readily degradable organic compounds (such as VFAs) persisted due to a combination of the effects of a high initial concentration of these acids (2.4 g/l as dissolved organic carbon, DOC) applied to carbon starved soil microorganisms and the small pore size of the compacted clay. Once the significant amounts of gas were generated from fermentation, conditions developed for improved mass transport and exchange of the nutrients and bacteria and the outcome of the intrinsic degradation was more apparent. The breakdown of VFAs that followed after the lag was localized near the top of the soil and was characterized by a short half-life of 0.75-5 days for DOC (total VFAs as dissolved organic carbon).     

废食用油脂作生物柴油原料的可行性分析

分析了各国废食用油脂的产生、回收和法规管理现状。重点通过分析废食用油脂物化性质，评价利用废食用油脂制造生物柴油的工艺特征和技术可行性。探讨了利用废食用油脂制造的生物柴油产品的品质和环境效益以及使用要求。同时分析了利用废食用油脂制造生物柴油的经济成本和存在的问题。     

高温好氧消化污泥对生物除磷的强化作用初探

由于高温好氧消化(TAD)后的污泥中常含有一定浓度的挥发性脂肪酸(VFA),为考察其对生物除磷系统的影响,通过将TAD污泥上清液与乙酸钠进行磷去除作用的对比试验。表明在厌氧条件下,加入TAD污泥的上清液,会使大量的P释放,磷释放规律及其释放速度均与乙酸钠造成的磷释放相当,因此,可以考虑将高温好氧消化污泥或上清液回流作为一种补充碳源,以强化生物除磷系统的除磷效果。但实际应用中,还要考虑到VFA降解以及回流污泥中的氮磷负荷,而且长期回流还需要进一步的试验验证。     

纳米富勒烯对土壤酶活性和微生物群落的影响

采用室内暗培养试验,研究了纳米富勒烯对土壤呼吸强度、酶活性及微生物结构群落多样性的影响.结果表明,添加纳米富勒烯抑制了土壤呼吸强度(p0.05),较对照处理CO_2累积量降低了1.2%～11.3%.纳米富勒烯显著抑制了土壤脲酶活性(p0.05),与对照相比,降低了19.1%～33.7%,土壤脱氢酶活性整体上表现为随纳米富勒烯添加量增加先增加后降低的趋势.与之相反,添加不同剂量纳米富勒烯整体上提高了土壤碱性磷酸酶活性,但差异不明显(p0.05).利用磷脂脂肪酸(Phospholipid Fatty Acids, PLFAs)分析发现,添加纳米富勒烯(10～500 mg·kg~(-1))后土壤总PLFAs含量较对照降低了3.6%～27.3%,在低剂量(≤50 mg·kg~(-1))纳米富勒烯处理下革兰氏阳性细菌、革兰氏阴性细菌、真菌、细菌含量均有所提升,而当纳米富勒烯剂量达到500 mg·kg~(-1)时,土壤微生物数量在不同程度上受到抑制.土壤微生物生态学指数(Shannon、Simpson和Pielou指数)、聚类分析(Cluster analysis)、主成分分析(Principal component analysis)均显示纳米富勒烯对土壤中微生物群落多样性产生了负面影响.     

Dynamic Modeling of the Ratio Volatile Fatty Acids/Bicarbonate Alkalinity in a UASB Reactor for Potato Processing Wastewater Treatment

In this work, dynamic mathematical model for the prediction of the operational parameter volatile fatty acids/bicarbonate alkalinity (VFA/ALK) in a UASB reactor was developed. The dynamic modeling technique was applied successfully to a two-year data record from an industrial wastewater treatment plant of a potato processing industry. The technique used included regression analysis by residuals. Seventeen parameters were examined including the following: wastewater's flow rate, reactor's temperature and pH, total and soluble influent COD, wastewater's temperature and pH, total and soluble effluent COD, volatile fatty acids, alkalinity, biogas production rate and each parameter with a time lag of up to 10 days. Finally, after all parameters and all time lag trials the best fitted model was developed. The model's adequacy was checked by χ² test for a data record of the same UASB reactor but at a different time period and proved to be satisfactory. Additionally, the model's ability to predict and to control the plant's operation via VFA/ALK was examined. Through this model, in contrary to steady state models, various aspects of the process can be enlighten, such as the fact that the hydrolysis of starch requires at least a resident time of seven days.     

油酸钠对餐厨垃圾两相厌氧发酵中利用乙酸产甲烷过程的影响

为了研究餐厨垃圾油脂中含有的长链脂肪酸(主要是油酸)对两相厌氧发酵中利用乙酸产甲烷过程的影响,采用中温(35±1)℃批式发酵,以浓度为10 g·L~(-1)的餐厨垃圾厌氧发酵产甲烷相出水为接种液,以乙酸为底物,考察了添加不同浓度油酸钠对累积甲烷产量、产甲烷古菌数量以及发酵过程中乙酸代谢和氢气分压的影响.结果表明:1产甲烷延滞期随油酸钠浓度增加而延长.2油酸钠浓度低于6.0 g·L~(-1)的处理组经过延滞期后乙酸代谢恢复正常,可以完全被转化为甲烷,且部分油酸钠也可被转化为甲烷;油酸钠浓度高于8.0 g·L~(-1)的处理组乙酸代谢受到严重抑制,只有少量甲烷生成;油酸钠生成中间代谢产物,且甲烷转化率为0.3油酸钠对厌氧发酵中产甲烷古菌有严重的抑制作用,产甲烷古菌数量大幅度减少是乙酸代谢过程受到抑制的主要原因.4油酸钠的添加量超过6.0 g·L~(-1)时,在发酵初期会引起产甲烷相中氢分压的升高,也证实了油酸钠对厌氧发酵的抑制作用.