小球藻生长及关键营养元素代谢规律的研究

[目的]探索小球藻生长过程中关键营养元素代谢的基本规律,优化小球藻大规模培养工艺。[方法]以新型、高效的平板气升环流式光生物反应器为模式反应器培养小球藻,定时检测均匀鼓泡流下小球藻的生长状况和培养液中氮、磷、钾、钙、镁、铁等关键营养元素的浓度。[结果]小球藻在264 h内的干重浓度接近线性增加趋势;铁元素在48 h后几乎消耗殆尽;氮和磷元素在168 h后降至较低水平;镁和钙元素在96 h降至较低水平后不再明显下降;钾元素虽然是小球藻生长的重要组成元素,但其浓度始终处于波动状态,变化并不显著。[结论]小球藻的元素代谢主要发生在168 h前,各种元素的代谢速率有显著差异;生长后期虽然大多数营养元素比较缺乏,但在持续光照和通入足够二氧化碳的条件下小球藻仍然可以继续生长一段时间。     

小球藻的分离及其DNA提取方法的研究

[目的]从湖水中分离小球藻并提取其DNA。[方法]采用稀释法及水滴法分离小球藻,优化小球藻培养条件,并用改良CTAB法及SDS法提取其DNA。[结果]温度20~25℃、光照4.39~5.86W/m2及转速100~150 r/min的条件适于小球藻的培养;改良CTAB法适于提取小球藻DNA。[结论]该研究将有助于在分子水平研究小球藻,促进小球藻的开发和利用。     

不同壳聚糖改性黏土对小球藻的絮凝效应及絮凝条件优选

微藻个体微小,不易采收,为其开发利用带来了很大困难。利用酸性壳聚糖对3种不同类型的黏土矿物(膨润土、硅藻土、沸石)进行改性,制备无公害复合絮凝剂,探究其对小球藻(C.pyrenoidosa)的絮凝效果,并考察了复合絮凝剂的浓度、静置时间、藻液p H值和壳聚糖与黏土矿物的比例对絮凝率的影响。结果表明:复合絮凝剂的絮凝效果明显高于壳聚糖。其中壳聚糖改性硅藻土对小球藻的絮凝效果最佳,其最佳絮凝条件为p H值为8,壳聚糖和硅藻土的配比为1∶6,浓度为0.2 g/L,沉降120 min。在该条件下,小球藻的絮凝采收率可达到约96.16%。复合絮凝剂无毒环保,不会造成二次污染影响微藻生物质后续加工利用,是一种环境友好,安全健康的微藻絮凝剂,具有良好的应用前景。     

Fe~(3+)对鳗池中铜绿微囊藻和小球藻生长的影响

以铜绿微囊藻(Microcystis aeruginosa)和小球藻(Chlorella vulgaris)为研究对象,分别测定了初始Fe3+摩尔浓度为0、1、10、15、20、25、50、100μmol·L-1时铜绿微囊藻和小球藻的生长曲线和叶绿素a含量。结果表明,2株藻均存在铁限制,其中缺铁对铜绿微囊藻生长的限制较为显著,当初始Fe3+浓度为0,1μmol·L-1时,其生长曲线呈现出负增长的趋势;铜绿微囊藻的μmax出现在25μmol·L-1,小球藻的μmax则出现在20μmol·L-1;当浓度为100μmol·L-1时,2株藻的生长均受到了一定的抑制,但此时的生长速度仍高于低Fe3+组。     

蛋白核小球藻无菌培养体系的建立

[目的]为了建立蛋白核小球藻无菌培养体系。[方法]选取卡那霉素、链霉素、庆大霉素、氨苄青霉素、潮霉素和头孢霉素6种常用抗生素,比较蛋白核小球藻的除菌和纯化效果。同时,对比蛋白核小球藻对不同浓度的卡那霉素和潮霉素的耐受性以及单独使用卡那霉素和潮霉素的多次除菌效果。[结果]卡那霉素和潮霉素对涂布带菌藻液的抑菌和除菌效果明显,其他4种抗生素的抑菌效果较差;小球藻对不同抗生素的耐受性不同,蛋白核小球藻对潮霉素敏感,50 mg/L就可以明显抑制其的生长,而对卡那霉素的敏感性要低得多,在200 mg/L时其生长受到显著抑制。[结论]考虑到高浓度卡那霉素对蛋白核小球藻生长的抑制作用,最终确定用50 mg/L卡那霉素连续3次除菌处理的方式建立蛋白核小球藻的无菌培养体系;同时,测得纯化培养的蛋白核小球藻藻液在685 nm处具有最大吸收峰,在此波长下小球藻的细胞浓度与吸光值呈线性相关,可用A685来估测蛋白核小球藻浓度。     

蛋白核小球藻处理猪场废水的效果观察

 研究一种微藻即蛋白核小球藻处理猪场废水的能力。将猪场废水稀释为3个不同浓度组,G₁组（100%废水）、G₂组（50%废水）、G₃组（25%废水）,分别加入等量蛋白核小球藻,分析其对猪场废水的处理能力。结果表明,蛋白核小球藻处理猪场废水浓度为50%时(COD、TN和TP分别为296 mg/L、64 mg/L和7 mg/L)具有最佳效果;微藻生长浓度前2 d和4 d分别达到0.029 g/L和0.016 g/L,对COD、TN和TP去除率分别达到80.07%、79.69%和87.14%。说明蛋白核小球藻对稀释50%的猪场废水具有较强的处理能力。     

Effects of daphnia (Moina micrura) plus chlorella (Chlorella pyrenoidosa) or microparticle diets on growth and survival of larval loach (Misgurnus anguillicaudatus)

Culture performance beyond metamorphosis of larval loach (Misgurnus anguillicaudatus) was examined in a feeding experiment of the early development stage (20 days after hatch; DAH). Total length, dry weight, length- and weight-specific growth rate (SGR) and survival were monitored in different diet regimes. During 20 days, diet treatments included: microparticle diets (A); live daphnia (Moina micrura) (B); live daphnia plus live chlorella (Chlorella pyrenoidosa) (C); and live daphnia plus microparticle diets (D). Fish survival rates during 20 days were 21.23 ± 4.2% (A), 73.19 ± 2.8% (B), 90.76 ± 3% (C) and 91.46 ± 3.1% (D), respectively. Length- and weight-specific growth rate after 20 DAH (final mean SGR; % day⁻¹) were 5.36 ± 0.44 and 15.75 ± 1.52 (A), 9.29 ± 1.25 and 23.47 ± 2.23 (B), 9.42 ± 1.55 and 24.88 ± 2.9 (C) and 9.55 ± 1.23 and 24.40 ± 2.75 (D), respectively. Fish in treatments B, C and D displayed higher growth rates and were significantly longer and heavier than fish in treatment A by the end of the experiment (Ρ < 0.05). Fish in treatment A had highly significant greater (Ρ < 0.001) mortalities than in treatments B, C and D. There were no significant differences in any growth parameter between fish in treatments B, C and D, but the survivals in treatments C and D (90.76% and 91.46%) were significantly higher than in treatment B (73.19%, Ρ < 0.05). The results demonstrated that enriched prey and co-feeding may serve as a potential feeding strategy for loach larvae, and the form of co-feeding reduces the costs and dependence on live foods to a certain extent. We concluded that larval loach should be reared over metamorphosis using either of the following methods: feed with live daphnia supplemented with microparticle diets or with live chlorella. However, a prolonged rearing period of loach larvae is needed to detect nutritional problems and observe remote effects of co-feeding on weaning in the future.     

利用季铵盐有机改性铝污泥絮凝除藻试验

选择具有良好吸附沉降性能的给水厂副产物铝污泥作为下沉载体替代粘土,探究季铵盐十六烷基三甲基溴化铵(CTAB)对铝污泥的吸附改性,并将其用于常见淡水小球藻(Chlorella)的絮凝去除试验。结果显示:(1)经600℃焙烧后的铝污泥对浓度为36.4 mg/L的CTAB改性溶液吸附能力最强,10 min内即可达到吸附平衡,吸附容量为9.19 mg/g;(2)当改性铝污泥中原始用量为3.0 g/L时,24 h后对藻密度和浊度的去除率可分别达到80.25%和80.05%;(3)改性剂CTAB不会影响铝污泥对磷酸盐的吸附性能,改性前后的铝污泥对磷的最大吸附率分别为90.91%和90.77%,且都在2 h左右达到吸附平衡。研究表明,有机改性铝污泥可初步形成一个除藻抑藻体系,可为藻类的去除和铝污泥的资源化利用提供理论依据及技术支持。     

Effect of living cells of microalgae or their extracts on soil enzyme activities

The enzymatic activity of the soil and potential plant growth can both be affected by the addition of different substances, such as biostimulants. The final objective of this work was to evaluate the effect of Chlorella vulgaris, Scenedesmus quadricauda or their extracts applied directly into the soil, by monitoring the complex soil-microorganism-plant system. Experiments were conducted in pots using agricultural soil and tomato plants in a growth chamber at 25 ± 2 °C illuminated by artificial light with a 16-h photoperiod. The soil biological activity was analyzed by monitoring fluorescein diacetate hydrolysis, dehydrogenases, acid and alkaline phosphomonoesterase and urease activities. Dry weight and chlorophyll index values of tomato plants were also investigated. Results showed that both the microalgae and their extracts positively affected soil biological activity by increasing values of the biochemical index of potential soil fertility (Mw) both in cultivated and uncultivated soils. The highest Mw value was reached in cultivated soil treated for 11 days with the lower concentration of S. quadricauda extract (Mw 9.47). All treatments significantly increased the growth of tomato plants with respect to untreated soil. These results are very promising with a view to improving soil biological activity as well as increasing plant growth.     

硒对异养小球藻生长及品质的影响

从可溶性糖、蛋白质、色素、Vc含量以及生物量等方面,探讨了不同浓度硒处理对异养小球藻生长及品质的影响。结果表明,硒对小球藻生长过程中及体内主要化学物质的影响显著。随着硒浓度的增加,可溶性糖、Vc、叶绿素b的含量均呈显著下降趋势,而生物量、蛋白质、叶绿素a和类胡萝卜素含量则呈先升后降趋势。当硒浓度增加至25 mg/L时,小球藻的生长即受到明显的抑制,各种化学物质的含量均显著下降。表明一定量的硒有利于异养小球藻的生长及其品质的改善。