烟草下脚料发酵制取乙醇

通过单因素实验考察了硫酸浓度、固液比和水解时间对硫酸水解的影响。结果显示最优条件为:硫酸浓度为50%(w/w),固液比为10%(w/v),时间为100 min。烟草下脚料在最佳硫酸水解条件下,经5倍稀释,中和pH值至5～6。取经过滤后的水解液(FH)用酿酒酵母(Sacchharomyces cerevisiae)发酵产生乙醇,最大的乙醇浓度和乙醇产量分别为1.09g/L和54.5 g/kg。未过滤水解液(UFH,包括水解残渣)加入纤维素酶(70 U/100 mL)和酿酒酵母(Sacchharomyces cerevisiae)进行发酵,最大的乙醇浓度和乙醇产量分别为1.23 g/L和61.5 g/kg。     

Kinetics study of fermentative hydrogen production from liquid swine manure supplemented with glucose under controlled pH

Kinetics of H₂ production from liquid swine manure supplemented with glucose by mixed anaerobic cultures was investigated using batch experiments under four different pH conditions (4.4, 5.0, 5.6, and uncontrolled). The temperature for the experiments was controlled at 37 ± 1°C and the length of experiments varied between 50 and 120 hours, depending upon the time needed for completion of each individual experiment. The modified Gompertz model was evaluated for its suitability for describing the H₂ production potential, H₂ production rate, and substrate consumption rate for all the experiments. The results showed that the Gompertz model could adequately fit the experimental results. The effect of pH was significant on all kinetic parameters for H₂ production including yield, production rate and lag time, and the substrate utilization rate. The optimal pH was found to be 5.0, at which a maximum H₂ production rate (0.64 L H₂/h) was obtained, and deviation from the optimal pH could result in substantial reductions in H₂ production rate (0.32 L H₂/h for pH 4.0 and 0.43 L H₂/h for pH 5.6). The results also showed that if pH was not controlled for the batch fermentation process, the substrate utilization efficiency could steeply decrease from 98.8% to 33.7%.     

响应面法和神经网络优化Acinetobactersp．DNS32发酵基质

为了提高阿特拉津降解菌Acinetobactersp．DNS32的产量，分别采用响应曲面法和基于人工神经网络的遗传算法对阿特拉津降解菌DNS32发酵培养基中3个重要基质成分（玉米粉、豆饼粉、K：HPO。）进行优化研究。响应曲面法确定3种成分的含量为玉米粉39．494g／L，豆饼粉25．638g／L和K。HPO。3．265g／L时，预测发酵活菌最大生物量为7．079×10^8CFU／mL，实测量为7．194×10^8CFU／mL；人工神经网络结合遗传算法优化确定3种主要成分含量为玉米粉为39．650g／L，豆饼粉为25．500g／L，K2HPO4为2．624g／L时，预测最大值为7．199×10^8CFU／mL，实测量为7．244×10。CFU／mL；最终确定培养基配方：玉米粉为39．650g／L，豆饼粉为25．500g／L，K2HPO4为2．624g／L，CaCO3为3．000g／L，MgSO4·7H2O和NaCl均为0．200g／L；优化后阿特拉津降解菌DNS32发酵生物量比优化前提高了36．6％。结果表明，在阿特拉津降解菌DNS32发酵培养基组分优化方面，响应面法和基于人工神经网络的遗传算法都是可行的，基于人工神经网络的遗传算法具有更好的拟合度和预测准确度。     

水稻与棉花秸秆不同预处理厌氧发酵产沼气

以猪粪为接种物,以棉花秸秆和水稻秸秆为发酵原料,分别对秸秆进行稀碱法预处理和稀碱法与超声波联合预处理,在发酵温度为(37±1)℃的条件下进行厌氧发酵产沼气的研究。结果表明,以联合预处理的秸秆为发酵原料,厌氧发酵的各项指标均比以稀碱预处理秸秆发酵的效果好,其中累积产气量和沼气中甲烷含量分别提高35.23%和2.4%,发酵后TS、VS含量相对减少2.6%～10.94%,发酵液代谢产物中的有机酸丙酮酸、乙酸和柠檬酸含量相对减少23.9%～25.9%、20.24%～24.53%和41.08%～45.91%。     

水生植物酸碱预处理对厌氧发酵联产氢气-甲烷的影响简

采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇，通过厌氧发酵动力学分析、还原糖变化及微观结构解析，研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明，酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高，酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳，最大氢气、甲烷含量分别达42.65%和52.82%，产氢气速率为4.118 mL/h，产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳，最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明，酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构，有效增加植物与微生物接触面积，有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。     

培养藻类制取生物能源的研究

能源紧张和环境污染是全世界所面临的共同问题，用藻类替代传统作物生产生物能源是生物质能的重要发展方向之一。文章介绍了国内外对藻类培养条件、光生物反应器型式、藻类基因工程、藻细胞收集方法以及能源藻类生产系统的研究成果。研究认为，以藻类为原料生产生物燃料具有良好的发展前景，并指出了今后能源藻类生长的重点研究方向。     

Development of a bird integrity index: using bird assemblages as indicators of riparian condition

We describe the development of a bird integrity index (BII) that uses bird assemblage information to assess human impacts on 13 stream reaches in the Willamette Valley, Oregon, USA. We used bird survey data to test 62 candidate metrics representing aspects of bird taxonomic richness, tolerance or intolerance to human disturbance, dietary preferences, foraging techniques, and nesting strategies that were affected positively or negatively by human activities. We evaluated the metric responsiveness by plotting each one against a measure of site disturbance that included aspects of land use/land cover, road density, riparian cover, and stream channel and substrate conditions. In addition, we eliminated imprecise and highly correlated (redundant) metrics, leaving 13 metrics for the final index. Individual metric scores ranged continuously from 0 to 10, and index scores were weighted to range from 0 to 100. Scores were calibrated using historical species information to set expectations for the number of species expected under minimally disturbed conditions. Site scores varied from 82 for the least disturbed stream reach to 8.5 for an urban site. We compared the bird integrity index site scores with the performance of other measures of biotic response developed during this study: a fish index of biointegrity (IBI) and two benthic macroinvertebrate metrics. The three assemblages agreed on the general level of disturbance; however, individual sites scored differently depending on specific indicator response to in-stream or riparian conditions. The bird integrity index appears to be a useful management and monitoring tool for assessing riparian integrity and communicating the results to the public. Used together with aquatic indicator response and watershed data, bird assemblage information contributes to a more complete picture of stream condition.     

乌鲁木齐市生态环境现状调查

乌鲁木齐市深居亚欧大陆腹地,远离海洋,气候干旱,降水稀少,植被稀疏,风沙危害严重,生态极期脆弱,属典型的温带半干旱绿洲生态环境。对乌鲁木齐市“八五”及“九五”期间的生态环境状况进行了多方面的调查分析。并就存在的问题谈了作者的观点,以供同行参考。     

EFFECTS OF INITIAL ABSTRACTION AND URBANIZATION ON ESTIMATED RUNOFF USING CN TECHNOLOGY1

ABSTRACT: Few studies have been conducted to explore the effects of initial abstraction on estimated direct runoff despite the widespread use of the curve number (CN) method in many hydrologic models to estimate direct runoff. In this study, use of a 5 percent ratio of initial abstraction (I_a) to storage (S) to estimate daily direct runoff with modified CN values for a 5 percent I_a/S value was investigated using the Long‐Term Hydrologic Impact Assessment (L‐THIA) geographic information system (GIS). In addition, the effects on estimated runoff of altering the hydrologic soil group due to urbanization were investigated. The L‐THIA model was applied to the Indiana Little Eagle Creek watershed with 5 percent and 20 percent I_a/S values, considering hydrologic soil group alteration due to urbanization. The results indicate that uses of a 5 percent l_a/S and modified CN values and Hydrologic Soil Group D for urbanized areas in model runs can improve long term direct runoff prediction.     

金沙江水电资源梯级开发及其经济发展研究

金沙江流域是我国13大水电基地中水能资源蕴涵量最大的地区，但开发率相对较低。在介绍金沙江流域丰富的水电资源及其开发现状的基础上，分析了加快金沙江水电开发的可能条件和重要意义；针对开发中存在的主要问题，根据市场经济原则和具体情况提出了对策和建议。