Microbiology Teaching Practice and Application in Engineering Undergraduates

本文对我系本科课程微生物学教学实践等进行了有益的探索,确定了将微生物学所涉及理论知识与工业过程联系起来,引导学生学习,激发学生兴趣,本文希望对学生读者有理解和促进作用,与教师读者共同探讨,研究该门课程的教学规律。In this paper, the author made a useful exploration on undergraduate courses such as microbiology teaching practice, to determine the microbiology involved in the theory of knowledge and industrial processes linked to guide student learning, to stimulate student interest, the paper in the hope that the students have to understand and promote the role of the reader to discuss with teachers readers to study the teaching law of the course

The use of experimental data and the application of a kinetic model to determine the subcellular distribution of Zn/Cd/Ni/Cu over time in Indian mustard

National Natural Science Foundation of China [21077056, 41071212, 41071302, 41171193]; Program for New Century Excellent Talents in University [NCET-12-0326]; Natural Science Foundation of Jiangsu Province [BE2011780]; Fundamental Research Funds for the Central Universities of China [KYZ201109]; Fok Ying Tung Education Foundation [122045]The precise subcellular distribution of metallic elements in plants may have a significant impact on metal detoxification and bioaccumulation processes. In this study, we report the subcellular distribution of metallic elements in Indian mustard (Brassica juncea) and the application of a kinetic model to confirm the experimental data by aqua-culture experiment. The metals in Indian mustard were determined on the 3rd, 5th, 9th, and 14th day. The results showed that concentrations of Zn, Cd, and Ni in root samples increased with exposure time, reaching maximum values of 13 161, 9602, and 864 mg kg(-1) (DW), respectively, at the 9th day, while concentrations of Cu in root samples reached a maximum value of 17 566 mg kg(-1) (DW) on the 14th day. A decrease in the concentration of Cu/Zn/Cd/Ni from roots to stem/leaf was observed, however, the difference in metal concentration between the roots and stem/leaf was much greater for Cu than for the other three metals. The majority of these metals were present in the cell walls, organelles, and the soluble fraction, with only minor amounts present in the cell membranes. The Zn, Cd, Ni and Cu existed mainly in the cell walls of the root on the 14th day, reaching maximum values of 424, 483, 23 and 839 mg kg(-1) (fresh samples), respectively. Nearly all (90%) of the Cu existed in the cell water-soluble fraction of stems and leaves on the 3rd day, however, 44%-52% of Cu was present in the cell water-soluble fraction on the 14th day. There were also 25%-35% of Zn, 53%-60% of Cd and 70%-73% of Ni in the cell water-soluble fraction of stems and leaves. The kinetic model adequately described the experimental data for accumulation by roots, stems, and leaves. The majority of the data for the subcellular fractions of roots and stems fit the equations well. The accumulation rate constant k and the maximum accumulation capacity y(max) of plant and subcellular fractions were calculated. Our results provide insight into the accumulation and subsequent subcellular distribution of metals in plants in hydroponics culture and will be valuable for further studies of phytoremediation

脉冲电源电解处理含氰含银电镀废水

利用脉冲电源从含氰含银电镀废水中回收银和去除氰,对比了脉冲电源与直流电源对含氰镀银废水的处理效果,系统研究了脉冲电源的电解电压、占空比和脉冲频率等参数对电能消耗、银回收率和除氰率的影响。结果表明,脉冲电源较直流电源能更加有效降低阳极的超电位,减少电极的极化,从而降低槽电压,进而有效地降低电能消耗。脉冲电源的优化参数是:脉冲电压2.0V,脉冲频率1200Hz,占空比50%。在循环流速100ml.min-1,pH值10～11,曝气速率1.0L·min-1的实验条件下,通入电解电压2.0V、脉冲频率1200Hz以及占空比50%的脉冲电源,电解2.0h后,银回收率高达99%,除氰率达到86%

高速电镀银漂洗水的近零排放技术

利用逆流漂洗和逆流蒸发联合装置实现高速电镀银漂洗水的近零排放。该联合装置中逆流漂洗由三级漂洗槽组成,而逆流蒸发包含电镀槽、填料蒸发器、过滤机和风机等。实际镀液实验表明,在保持一定的液位水平和第三槽漂洗水的浓度小于20 mg/L的前提下,系统运行稳定,没有向外界排放含银漂洗废水,新鲜漂洗水用量比原来节省超过90%,实现电镀银过程的节水高效和漂洗水近零排放

Diversity of bacterial community structure and its driving factors in three bays of Bohai Sea

[Background] Sustainable development of coastal ecosystem has become one of the most important concerns for people nowadays. Riverine output and anthropogenic interrupt have important impacts on the coastal environment. [Objective] In this study, we collected 12 samples from three transects including Bohai Bay, Liaodong Bay and Laizhou Bay to explore the microbial community and diversity in summer of 2015. [Methods] DNA was extracted from water samples by using DNA extraction kit. Samples were analyzed by Illumina HiSeq sequencing technology. We compared the differences among these three transects according to the analysis results. [Results] The diversity index and rarefaction curves showed significant differences among these three transects. The order of diversity value was Laizhou Bay>Bohai Bay>Liaodong Bay. The distribution of the dominant community was as follows: the proportion of Proteobacteria, Bacteroidetes, Cyanobacteria, Actinobacteria and Planctomycetes in the Bohai Bay was 39.8%, 25.7%, 22.4%, 5.85% and 4.38%, respectively. The dominant community proportion in Liaodong bay was Proteobacteria (37.8%), Bacteroidetes (25.7%), Cyanobacteria (17.8%), Actinobacteria (10.4%) and Planctomycetes (5.64%). While in Laizhou Bay there were only four dominant communities as follows: Proteobacteria (59.0%), Bacteroidetes (17.5%), Cyanobacteria (8.2%), Actinobacteria (7.88%). By using the principal component analysis (PCA) and Heatmap correlation analysis, we found that environmental factors were key roles in controlling the microbial diversity in the Bohai Sea. Among them, the concentration of nitrate was particularly significant according to the Mantel test analysis. [Conclusion] The microbial diversity in the three bays of Bohai Sea was very rich and multifarious. The population structure and species in the Laizhou Bay is the most complex and abundant among these three bays, and then it is Bohai Bay and Liaodong Bay. There was a significant correlation among microbial diversity, environmental factors and the spatial distribution. Above all, this study will provide a theoretical basis for further protection and ecological development of Bohai Sea

Polyphenol Contents in Eight Fruits and Their Antioxidant Activities

[中文摘要]测定了苹果、石榴、橄榄、芒果、香蕉、菠萝、葡萄和龙眼的壳、肉及核中的多酚含量及其抗氧化性。以70%丙酮(v/v)为提取溶剂,室温下超声波辅助浸提样品后得到提取液。采用普鲁士兰(Prussian blue)法测定了提取液中多酚和单宁的含量,利用FRAP法测定其抗氧化性。结果表明:提取液中多酚和单宁的含量均与其抗氧化性成正相关关系;石榴、橄榄、芒果、葡萄和龙眼等水果的壳与核有望成为天然抗氧化剂的新来源。[英文摘要]The contents o f polyphenols of peel pulp and seed fractions of apple, pome granate, olive, mango, banana, pineapple, grape and long an and their to talantioxidant ac tiv ities were studied. A fter ultrasound-assisted extraction w ith 70% aqueous acetone at room temperature, polypheno ls and tann ins in the p lant ce lls w ere separated and their contents were determ ined by Prussian blue assay. Antioxidant activities of the aqueous acetone extracts were evaluated by Ferric Reducing /Antioxidant Power (FRAP) assay. A positive linear correlation between antioxidant activities and phenolic contents was observed. The resu lts show ed that the fru it pee l and seeds o f pom egranate, olive, mango, grape and longan could be conside red as potentia l sources o f antioxidants rather than just discarded as waste

Component analysis and risk assessment of anaerobically digested slurry from households in China

采集了中国8个省市的43个不同原料家庭户用沼气池的沼液,进行化学需氧量(COd)、氨氮(nH+4-n)、磷酸盐(PO43？)和重金属等指标分析,阐述不同原料导致沼液成分的差异,评价了不同来源沼液存在的生态风险,旨在为不同来源沼液的资源化利用提供理论依据。研究结果表明,以牛粪和秸秆为原料的沼液COd浓度较高,分别达到6800 Mg·l？1和5800 Mg·l？1;以猪粪和混合粪便为原料的沼液氨氮浓度较高,都超过1800 Mg·l？1,而牛粪原料沼液氨氮浓度明显低于其他原料,平均值仅有450 Mg·l？1,因此以牛粪为原料的沼液COd/nH+4-n显著高于其他三种原料,COd/nH+4-n达到15,而其他三种原料的沼液COd/nH+4-n均低于5;所有原料沼液磷酸盐浓度的平均值均低于80 Mg·l？1;沼液中汞的污染较严重,且在不同原料和不同地区的沼液中具有普遍性;潜在生态风险指数rI分析结果表明,云南、河南和湖北的沼液rI介于130~260之间,属于中等生态危害,存在一定的生态风险。Forty-three biogas slurries from household biogas plants using different substrates were collected from different parts of China.The contents of chemical oxygen demand(COD), ammonium nitrogen(NH+ 4-N), phosphate(PO4 3?) and heavy metals were determined.The concentrations of COD in cow dung and straw as raw materials were higher than other treatments, reaching 6800 mg·L?1 and 5800 mg·L?1 respectively.The concentrations of NH+ 4-N in pig manure and mix manure were higher than other treatments, reaching more than 1800 mg·L?1..The concentration of NH+ 4-N in cow dung was significantly lower than that in other materials, with the average being 450 mg·L?1.Therefore, COD/ NH+ 4 ratio of 15 in the slurry with cow dung as raw material was significantly higher than those in other three materials(less than 5).The average PO4 3? concentrations of all raw biogas were lower than 80 mg·L?1.Mercury pollution was serious and universal in different materials and different provinces.Environment risk evaluation showed that the pollution in biogas slurries from Yunnan, Henan and Hubei was medium and could not be ignored.国家重点基础研究发展计划项目(2013CB733505)~

微波辅助萃取-大孔树脂分离纯化芳樟叶黄酮

为了综合利用芳樟叶精油提取过程中产生的大量残渣,该文利用微波辅助萃取和大孔树脂选择性吸附来分离纯化芳樟叶黄酮。采用L9(34)正交试验,考察了萃取剂、微波辐射功率、辐射时间及料液比对黄酮得率的影响,确定了微波辅助萃取的优化工艺条件:以60%乙醇做萃取剂,微波功率320W,间歇辐射2次,每次1min,料液质量体积比1:12,在此条件下,芳樟叶黄酮的提取得率为2.97%,与乙醇热回流提取方法相比,得率提高了6.83%,时间缩短了98.89%;为进一步纯化萃取所得的黄酮提取物,选择6种大孔吸附树脂,测定芳樟叶黄酮在树脂上的吸附量和解吸率,筛选出了吸附剂HPD-450,其对芳樟叶黄酮有较好的静态吸附和解吸效果。经装填有大孔树脂HPD-450的固定床纯化后黄酮纯度由22.49%提高到51.28%,纯化倍数2.3倍

Effect of pretreatment temperature on volatile fatty acids production by activated sludge

考察了预处理温度对剩余污泥水解酸化生产挥发性脂肪酸(VFAs)的影响。分别在70、80、90、100℃下处理剩余活性污泥2 h,考察其水解酸化情况。结果表明:热处理可提高溶液中的SCOD及碳水化合物含量,提高效果随温度升高而增大;预处理温度对污泥产酸的促进效果为:90℃>80℃>100℃>70℃。经加90℃处理的活性污泥在缺氧条件下水解酸化30 h后,VFAs的产酸量达到最大,为946 mg/L。VFAs包括乙酸、丙酸、丁酸和戊酸,其中乙酸和丙酸为主要产物,热预处理污泥可提高VFAs中乙酸的含量。The effect of thermal pretreatment temperature on solubilization an acidification of waste sludge(WAS) was investigated.Pretreatment temperatures of WAS ranged from 70℃ to 100℃ and holding time was 2 h.The results showed that COD solubilization was found to increase with treatment temperature.Whereas,total volatile fatty acid(TVFAs)concentration was found to be in the following order:90℃>80℃>100℃>70℃.The optimal pretreatment temperature was 90℃.The VFAs concentration of WAS pretreated under 90℃ was 946 mg/L after 30 h of fermentation.The VFAs consisted of acetic,propionic,butyric and valeric acids,but acetic and propionic acids were the two main products.The proportion of acetic acid was increased by thermal pretreatment.福建省科技重点项目(2008Y0060);; 厦门市科技计划项目(3502Z20073005);; 新加坡厦大校友会研发与学术交流基金项

Green Synthesis of Potassium Diformate

以甲酸和氢氧化钾为原料,不外加任何溶剂一步合成二甲酸钾。通过单因素实验,考察了原料配比、反应温度和反应时间对产品质量与收率的影响。采用正交实验进一步优化了合成工艺,确定了最佳工艺条件:n(HCOOH)/n(KOH)=2.2、反应温度70℃、反应时间30 m in,在该条件下,二甲酸钾产品收率达98%以上。所得产品经红外光谱分析及熔点测定,其结果与文献报道一致。反应过程绿色化,有很好的原子经济性。Potassium diformate was synthesized without solvent,using formic acid and potassium hydroxide as raw materials.The optimal conditions for the reaction were:molar ratio of HCOOH to KOH 2.2∶1,reaction temperature 70 ℃ and reaction time 30 min.Yield of the process was over 98% under the optimal conditions.The infrared spectrum and melting range of the product were in good agreement with those reported in literature.The technology developed in this study could be an environmentally benign synthesis route with efficient atom economy