近临界水中生物质固体废弃物水解制备氨基酸及水解液脱色研究

对废鱼肉、废禽畜肉及其加工过程产生的废弃物在近临界水中水解制备氨基酸和氨基酸水解液的脱色进行研究.反应器容积为200mL,反应温度为180～320 ℃,反应压力为5～26 MPa,反应时间为5～60 min.利用氨基酸分析仪对水解产物中的氨基酸进行定性和定量分析,实验结果发现,实验所用原料水解后可得到17种氨基酸.水解产物中不同种类氨基酸的产率随反应温度、反应压力和反应时间的变化规律各不相同.对其中8种含量较高、用途较广、附加值较高的氨基酸,分别进行了反应温度、反应压力、反应时间对水解液中氨基酸浓度的影响研究,得到了在较低的反应温度、合适的反应压力和一定的反应时间内获得较高氨基酸产率的水解条件.以颗粒状活性炭为脱色剂,对水解液在不同pH值、活性炭用量、吸附温度和吸附时间条件下进行脱色实验,并考察了脱色率和氨基酸损失率.结果表明,较好的吸附条件为:pH=4.0、活性炭用量为0.02g·mL-1、吸附温度40℃、吸附时间15min,脱色率96%;被活性炭吸附的氨基酸可以通过解吸附得到回收.     

城市污泥与园林废弃物混合堆肥施用对林地土壤微生物量碳、氮及酶活性的影响

研究城市污泥和园林废弃物混合堆肥施用对土壤微生物量碳(SMBC)、微生物量氮(SMBN)及酶活性的影响,可为林地施用混合堆肥产品的安全及功效性评价提供科学依据.本研究采用大田试验,选取紫穗槐为研究对象,将污泥和园林废弃物以3种比例(GF(纯园林废弃物)、SGA(V(污泥)∶V(园林废弃物)=1∶3)、SGB(V(污泥)∶V(园林废弃物)=1∶1))进行混合堆肥,每种堆肥产品分别按0、5、10、50 kg·株-1(分别记作CK、T5、T10、T50)均匀施入样地.施肥1年后,于田间采样测定土壤生物活性指标及理化性质,采用主成分分析及单、双因素方差分析法研究混合堆肥产品施用后对土壤酶活性及微生物量碳、氮含量的影响.结果表明:施入GF、SGA和SGB时,SMBC和SMBN均在施用量50 kg·株-1时达到最大.随着施用量的增加,土壤酶指数(SEI)总体上呈现逐步递增的趋势,施入GF、SGA、SGB时,各个施肥梯度处理的土壤酶指数较CK分别增加93.33%~186.67%、14.58%~54.17%、119.05%~204.76%.通过主成分分析,依据各处理综合得分情况,不同堆肥产品总体上表现为:SGBGFSGA.施入GF、SGA和SGB,不同处理综合得分均为T50T10T5CK.说明施用堆肥产品能够提高土壤微生物量,增加土壤酶活性,改善土壤的生物环境.     

Effects of vegetation type on soil microbial community structure and catabolic diversity assessed by polyphasic methods in North China

Soil microbes play a major role in ecological processes and are closely associated with the aboveground plant community.In order to understand the effects of vegetation type on the characteristics of soil microbial communities,the soil microbial communities were assessed by plate counts,phospholipid fatty acid (PLFA) and Biolog microplate techniques in five plant communities,i.e.,soybean field (SF),artificial turf (AT),artificial shrub (AS),natural shrub (NS),and maize field (MF) in Jinan,Shandong Province,North China.The results showed that plant diversity had little discernible effect on microbial biomass but a positive impact on the evenness of utilized substrates in Biolog microplate.Legumes could significantly enhance the number of cultural microorganisms,microbial biomass,and community catabolic diversity.Except for SF dominated by legumes,the biomass of fungi and the catabolic diversity of microbial community were higher in less disturbed soil beneath NS than in frequently disturbed soils beneath the other vegetation types.These results confirmed that high number of plant species,legumes,and natural vegetation types tend to support soil microbial communities with higher function.The present study also found a significant correlation between the number of cultured bacteria and catabolic diversity of the bacterial community.Different research methods led to varied results in this study.The combination of several approaches is recommended for accurately describing the characteristics of microbial communities in many respects.     

重金属铜、锌、镉、铅复合污染对土壤环境微生物群落的影响

以铜锌冶炼厂附近的水稻土为例 ,研究了重金属复合污染对土壤微生物群落的影响 .结果表明 ,有效铜、锌、镉、铅与微生物生物量碳、微生物生物量氮、微生物商、微生物生物量氮 全氮均呈显著负相关 .重金属污染均能降低细菌、真菌和放线菌的数量 .用BIOLOG生态盘研究了重金属污染对微生物群落结构的影响 ,发现重金属污染明显影响了微生物群落结构 ,反映在典型变量 1(CV1)与重金属元素含量呈极显著正相关 ,因此认为典型变量 1是反映重金属污染程度的有效指标 .经逐步回归分析发现 ,有效铜是影响典型变量 1最主要的因素 .     

淀山湖着生藻类群落结构与数量特征

在１９９３～１９９７－０６间对淀山湖５种沉水植物及人工基质上的着生藻类群落进行了研究。结果表明,沉水植物上着生藻类群落由３７属３９种藻类组成,其中硅藻门１３属１３种,绿藻门１２属１３种,蓝藻门６属７种。５种沉水植物上着生藻类群落密度和生物量,均以黑藻最高,金鱼藻次之,菹草居第３,人工基质（塑料板）介于金鱼藻和菹草之间;并于冬季达全年最高峰,夏季为全年最低。着生藻类生长与沉水植物生长间呈负相关,并限     

Bacterial diversity in soils around a lead and zinc mine

Five samples of soil collected from a lead and zinc mine were used to assess the effect of combined contamination of heavy metals on soil bacterial communities using a polyphasic approach including characterization of isolates by culture method, community level catabolic profiling in BIOLOG GN microplates, and genetic community fingerprinting by denaturing gradient gel electrophoresis of 16S rDNA fragments amplified by PCR from community DNA （PCR-DGGE）. The structure of the bacterial community was affected to a certain extent by heavy metals. The PCR-DGGE analysis of 16S rRNA genes showed that there were significant differences in the structure of the microbial community among the soil samples, which were related to the contamination levels. The number of bacteria and the number of denaturing gradient gel electrophoresis （DGGE） bands in the soils increased with increasing distance from the lead and zinc mine tailing, whereas the concentration of lead （Pb） and cadmium （Cd） was decreased. Heavily polluted soils could be characterized by a community that differs from those of lightly polluted soils in richness and structure of dominating bacterial populations. The clustering analysis of the DGGE profiles showed that the bacteria in all the five samples of soil belonged to three clusters. The data from the BIOLOG analysis also showed the same result. This study showed that heavy metal contamination decreased both the biomass and diversity of the bacterial community in soil.     

La0.5Ca0.5Ni0.5Fe0.5O3催化剂的制备及其对生物质热解特性的影响

采用共沉淀法制备了La0.5Ca0.5Ni0.5Fe0.5O3纳米粉体,并通过XRD、SEM、TG-DTA等手段对所合成的样品进行了分析和表征.结果表明,采用碳酸铵作为共沉淀剂、聚乙二醇为分散剂,在600℃下煅烧6h可作为实验制备该催化剂粉体的最优条件.用实验室自制热解催化炉验证其对生物质热解的效果,实验结果表明,采用La0.5Ca0.5Ni0.5Fe0.5O3催化剂,生物质热解过程中焦油产量降低了12.4%,气体产率提高了14.0%,气体产物中一氧化碳、甲烷含量分别从33.8%和15.1%提高到了38.5%和18.4%,燃气的品质大大提升.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

黄土高原典型土壤有机碳和微生物碳分布特征的研究

以阐明黄土高原典型区域土壤有机碳(SOC)含量和储量及微生物碳(Mc)含量随土壤类型、土层和土地利用方式变异规律为目的,研究了从北向南依次分布的干润砂质新成土(神木)、黄土正常新成土(延安)和土垫旱耕人为土(杨凌)等典型土壤的SOC含量和储量及Mc含量的变化特征。结果表明,不同土壤类型、不同土层SOC和Mc含量存在显著差异。同一土壤类型SOC和Mc含量在0～60cm随土层深度增加下降很明显,60～120cm土层有轻微下降,120cm土层以下低而稳定,同层次土壤从南到北,SOC、Mc和SOC储量含量显著下降,均以土垫旱耕人为土最高,黄土正常新成土次之,干润砂质新成土最低,且差异显著(P<0.05);0～200cm土层SOC总储量也沿土垫旱耕人为土(102.23±30.12t/hm²)、黄土正常新成土(67.78±9.23t/hm²)、干润砂质新成土(27.07±4.59t/hm²)依次下降;土垫旱耕人为土、黄土正常新成土和干润砂质新成土在100～200cm土层SOC累积量分别是0～100cm土层的65%、74%和58%,因此在研究黄土高原SOC贮量时必需考虑深层贮量的贡献。Mc随土壤类型的变化趋势与SOC基本相同,与SOC间存在极显著正相关关系(P<0.01);土壤Mc/SOC比值范围为0.005～0.05,土地利用仅对干润砂质新成土和土垫旱耕人为土SOC含量和储量影响显著(P>0.05),但对3种土壤Mc和Mc/SOC比值均产生显著影响;与农田土壤相比,草地土壤Mc和Mc/SOC比值均明显增加,这一结果说明用Mc和Mc/SOC比值更能有效反映土壤质量的变化。     

三江平原小叶章湿地土壤微生物活性特征研究

选取三江平原河滨湿地、沼泽湿地和草甸化湿地3种类型小叶章湿地0~20cm土壤,研究了不同类型湿地土壤总有机碳(TOC)、微生物生物量碳(MBC)、微生物生物量氮(MBN)、基础呼吸(BR)、呼吸势(PR)、微生物熵(Cmic/Corg)和代谢熵(qCO2)变化规律.结果表明,不同类型小叶章湿地土壤总有机碳、微生物生物量碳和基础呼吸分别为46.60~75.44g.kg-1、1106.86~2319.42mg.kg-1和5.72~10.10mg.kg-.1h-1.河滨湿地和沼泽湿地土壤总有机碳、微生物生物量碳、微生物生物量氮、基础呼吸、呼吸势和微生物熵均显著高于草甸化湿地(p0.01),而河滨湿地和沼泽湿地代谢熵明显低于草甸化湿地(p0.05).各土壤微生物活性指标在河滨湿地和沼泽湿地间均无明显差异.因而,相对于河滨湿地和沼泽湿地,草甸化湿地土壤微生物活性处于较低水平,土壤总有机碳和水分含量低是限制草甸化湿地土壤微生物活性的重要因素.