矿区土壤中砷污染对微生物群落的影响研究

采用梯度培养和PCR-DGGE技术,对大柳塔矿区矸石山及周边土壤的砷含量及其对土壤微生物群落的影响进行了研究,并通过测序研究了土壤微生物群落的结构。结果表明,矸石山及其周边自然表土的含水量较少,且十分相近;全磷和有机质含量普遍较高,p H呈中偏碱性;不同风化程度矸石山土壤砷含量对土壤微生物群落有显著的影响,不同砷污染负荷土壤中微生物群落的丰度存在差异;矸石山复垦年限不同,土壤理化性质会发生变化;土壤中砷含量的增高,对植物生长起关键作用的Gemmatimonas(甲烷单毛菌属)等微生物群落受到不同程度的抑制;Proteobacterium(变形菌门)具有较强的耐砷性;矸石山土壤特有的理化性质可为GASP-WA2W2_F11等微生物群落的演替创造了条件。     

涠洲采油废水处理系统运行效果及微生物群落分析

涠洲终端处理厂选用ABR+SBR联合工艺处理采油废水,该系统运行稳定,处理效果好。进水ρ(COD)、ρ(石油类)分别为215~731,9~52 mg/L,系统处理后出水浓度为30~87,2~8 mg/L,去除率为83%~94%,78%~92%。废水中其余指标如S2-、SS和NH3-N去除率分别为99%、94%和70%~90%。利用分子分析法对微生物群落结构研究,表明进水较出水有更高的细菌丰度,出水较进水有更高的真菌丰度。推测活性污泥中Marinobacterium、Marinobacter和Thiomicrospira是系统中采油废水主要降解细菌。此外,真菌群落分布均匀主要为子囊菌门、担子菌门、接合菌门,兼性菌如Aspergillus、Alternaria、Fusarium、Blastobotrys及Meyerozyma在活性污泥中较为丰富,Aspergillus、Alternaria可能是潜在的降解真菌。     

纳米氧化锌对EBPR系统的长期作用机制研究:从宏观到微观

研究了纳米氧化锌(ZnO NPs)对强化生物除磷(EBPR)系统的长期作用机制,系统分析了EBPR系统在ZnO NPs长期抑制下宏观运行性能与微观结构的变化.结果发现,当进水开始添加ZnO NPs后,系统沉降性能随之降低.厌氧释磷速率与好氧吸磷速率均出现显著降低并降至0 mg·g~(-1)·h~(-1)(以每g MLSS释(吸)P量(mg)计,下同),从而使得系统丧失除磷效果.同时,厌氧段COD开始积累.ZnO NPs浓度增加至10 mg·L~(-1)时,多糖与蛋白质含量在抑制条件下均开始减少.通过高通量技术对微观层面进行分析发现,ZnO NPs将会严重抑制聚磷菌的正常生长.ZnO NPs对系统内不同细菌有截然不同的作用,Proteobacteria门在试验过程中比例减小,而Bacteroidetes门却受到促进作用.恢复阶段,较低浓度(2 mg·L~(-1))抑制条件下,EBPR系统恢复速度与程度均优于高浓度(6、10 mg·L~(-1))抑制条件.然而,即使系统得到一定程度恢复也难以恢复到初始水平.     

好氧堆肥微生物降解土壤中硝基苯的影响因素研究

为进一步了解好氧堆肥降解土壤硝基苯的机理,从堆肥高温期筛选出能以硝基苯为唯一碳源和氮源的微生物,并研究了该菌系降解硝基苯的最佳条件。发现该微生物不能以葡萄糖作为共代谢底物,在p H值为5,当硝基苯初始浓度为25 mg/L时,生长情况最佳,且降解时间最短为84 h,对于100 mg/L的硝基苯最快96 h能完全降解。通过16s r DNA对该菌系进行鉴定表明,该微生物为粪产碱杆菌和戴尔福特菌,硝基苯降解途径为好氧条件下的JS765氧化途径。采用该微生物体系接种到硝基苯污染的土壤中,相比不接种处理组的硝基苯降解率提高了10%左右。     

Exponential Collapse of Benthic Depurative Capacity in A Eutrophic Tropical Marine Ecosystem: A Threshold Response to Organic Nitrogen Loading

Microbial decomposition of particulate organic matter in sediments can substantially modulate eutrophication of nearshore marine environments. Flux budgets for nitrogen compounds and quantification of rates of microbial transformation can provide important information on the process of eutrophication. This survey documents sediment nitrogen budgets for a eutrophic nearshore marine environment at La Parguera on southwest coast of Puerto Rico, including consideration of the organic fraction in addition to microbial transformations.

Sediments of the inshore channel at La Parguera denote the input of heavy organic loads with low redox potentials and high ammonium contents. Benthic fluxes of dissolved organic nitrogen are below those recorded for ammonium. These observations suggest that nearshore tropical sediments subject to heavy nitrogen loads act as a sink for organic nitrogen and that ammonification is a key process in the release of nitrogen from sediments to the water column. Nitrification and denitrification rates are low overall and inversely related to the redox potential. Depuration of excess nitrogen through denitrification is ineffective in these sediments. in contrast to more robust temperate environments, our work demonstrates that tropical marine systems are particularly susceptible to eutrophication given their limited capacity for depuration of excess nitrogen.     

Influence of benomyl and prometryn on the soil microbial activities and community structures in pasture grasslands of Slovakia

The effects of pesticides (a herbicide and a fungicide) on the microbial community structure and their activity were analyzed in soil from four alpine pasture grasslands in Slovakia. Specifically, the effects of the herbicide, Gesagard (prometryn active ingredient), and fungicide, Fundazol 50 WP (benomyl active ingredient), on the microbial respiration activity (CO₂ production), the numbers of selective microbial physiological groups (CFU.g^?1) and the structure (relative abundance) of soil microbial communities [(phospholipid fatty acid (PLFA)] were analyzed under controlled laboratory conditions. All treatments including the treatments with pesticides increased (statistically significantly) the production of CO₂ in all fields during 21 days of incubation and posed a statistically insignificant negative influence on the numbers of the observed physiological groups of microorganisms. The significantly negative influence was evaluated only in the numbers of two physiological groups; spores of bacteria utilizing organic nitrogen and bacteria, and their spores utilizing inorganic nitrogen. A shift in the microbial composition was evident when the PLFA patterns of samples from different sites and treatments were compared by the Principal Component Analysis (PCA). According to the second component PCA 2 (15.95 %) the locations were grouped into two clusters. The first one involved the Donovaly and Dubakovo sites and the second one contained the Velka Fatra and Mala Fatra locations. The PLFA composition of the soils showed important changes after the treatment with pesticides according to PCA 1 (66.06 %). Other treatments had not had a significant effect on the soil microbial community with the exception of the population of fungi. The lower relative abundance (significant effect) of Gram-positive bacteria, actinomycetes and general group of bacteria were determined in samples treated by the herbicide Gesagard. The application of fungicide Fundazol decreased (statistically significantly) the relative abundance of actinomycetes and general group of bacteria and paradoxically increased the population of fungi.     

放牧对张家界索溪峪景区土壤微生物区系及活度的影响

为了探明旅游对张家界景区土壤微生物的影响,进行了放牧对土壤微生物区系及活度的影响研究。结果表明:放牧显著影响了0～5cm土壤的细菌、放线菌、真菌总数,活动区的细菌和真菌等主要有机质分解菌明显低于缓冲区和背景区,而背景区的放线菌明显高于缓冲区和活动区。在5～15、15～25cm土壤层中,细菌和放线菌总数没有受到放牧的影响,但背景区和缓冲区的真菌总数均显著高于活动区,活动区的细菌在5～15cm土壤中最多,而放线菌和真菌数量均表现为随土壤深度增加而减少的趋势。在缓冲区和背景区土壤中,3类微生物的数量均随土壤深度增加而减少。放牧也对表层土壤中的好气性纤维素分解菌、嫌气性纤维素分解菌、好气性固氮菌、硝化细菌以及反硝化细菌等微生物生理群造成了显著影响。土壤微生物活度随土壤深度增加而降低。在0～5和5～15cm²个土壤层中,缓冲区和活动区的微生物活度均明显高于背景区,而缓冲区的微生物活度与活动区的微生物活度没有显著性差异,微生物活度表现为活动区>缓冲区>背景区;在15～25cm土壤层中,活动区与缓冲区的微生物活度没有显著性差异,缓冲区与背景区的微生物活度没有显著性差异,但活动区的微生物活度明显高于背景区的微生物活度。     

Changes in enzymes activity, substrate utilization pattern and diversity of soil microbial communities under cadmium pollution

Heavy metal pollution has received increasing attention in recent years mainly because of the public awareness of environmental issues. In this study we have evaluated the effect of cadmium （Cd） on enzymes activity, substrate utilization pattern and diversity of microbial communities in soil spiked with 0, 20, 40, 60, 80, and 100 mg/kg Cd, during 60 d of incubation at 25℃. Enzyme activities determined at 0, 15, 30, 45, and 60 d after heavy metal application（DAA） showed marked declines for various Cd treatments, and up to 60 DAA, 100 mg/kg Cd resulted in 50.1%, 47.4%, and 39.8% decreases in soil urease, acid phosphatase and dehydrogenase activities, respectively to control. At 60 DAA, substrate utilization pattern of soil microbial communities determined by inoculating Biolog ECO plates indicated that Cd addition had markedly inhibited the functional activity of soil microbial communities and multivariate analysis of sole carbon source utilization showed significantly different utilization patterns for 80 and 100 mg/kg Cd treatments. The structural diversity of soil microbial communities assessed by PCR-DGGE method at 60 DAA, illustrated that DGGE patterns in soil simplified with increasing Cd concentration, and clustering of DGGE profiles for various Cd treatments revealed that they had more than 50% difference with that of control.     

垃圾渗出液微生物循环强化培养菌剂在堆肥中的应用

针对垃圾堆肥过程中外加菌剂存在接种后菌剂活性衰退的问题,提出一种直接利用垃圾堆肥渗出液中微生物制备高效菌剂的方法．分别以堆肥高温阶段和中温阶段产生的渗出液中微生物为来源,利用自制培养基经4次循环强化培养制得高温菌剂和中温菌剂,进行了接种和不接种的好氧堆肥对比试验,测定了堆肥渗出液中微生物数量、堆体温度、纤维素酶活、pH和好氧速率等指标实验结果表明：(1)接种组渗出液中高温细菌、高温放线菌和高温霉菌数量平均是对照组的2．17倍;中温细菌、中温放线菌和中温霉菌数量平均是对照组的2．41倍,接种组微生物的数量明显多于对照组;(2)接种组的纤维素酶活性较对照组最大提高26%,且提前4d达到最大值;堆体耗氧速率在高温阶段和中温阶段分别提高37％和42．8％．说明接种后的微生物经过堆体微生态环境的自然选择作用,其代谢活性增强,对有机垃圾的降解能力明显提高,垃圾中纤维素更快地被分解和转化,有利于加快堆肥腐熟．