水体中悬浮泥沙对藻类生长的影响

藻类生长需要适当的光强,水体中悬浮物(如泥沙)的存在,势必对进入水体的光强产生抑制,从而影响藻类生长。通过实验研究了不同浓度和不同粒径的泥沙对藻类生长的影响,结果表明,适量的泥沙浓度反而使水体chla最大浓度比空白水体有所增大,100目粒径的泥沙对光线的阻隔作用最强。     

针对刚毛藻的植物源抑制剂的筛选及工艺优化

刚毛藻(Cladophora sp.)凭借强大的环境适应性异常增殖现象在淡水和海洋浅水区普遍存在。探讨了不同配置、不同提取方式及不同质量浓度的植物浸提液对刚毛藻生长及光合系统的影响,以期为刚毛藻的防治提供科学依据。结果表明:银杏叶、柳树叶及两种落叶复配后的水提液均能对刚毛藻的生长表现出极显著抑制效果,其中银杏叶水提液的抑藻效果最好,96 h时的生长抑制率可达66.65 %。此外,银杏叶水提液对刚毛藻的光合系统也产生了较高的抑制作用,96 h时最大PSⅡ光能转换效率 F_v/F_m、实际光化学效率Yield及非光化学淬灭参数NPQ的抑制率分别达96.69 %、99.22 %和78.06 %。不同提取剂对银杏叶浸提液抑藻效果的实验结果表明,银杏叶乙醇浸提液和丙酮浸提液对刚毛藻的生长抑制作用强于氯仿及水浸提液,其中银杏叶乙醇浸提液对刚毛藻光合系统的抑制效果最好,48 h时F_v/F_m、Yield及快速光曲线初始斜率α值抑制率均可达99 %。进一步研究不同浓度梯度银杏叶乙醇浸提液抑藻效果显示,浸提液质量浓度与抑藻效果存在正相关,3.00 g/L和6.00 g/L质量浓度组对刚毛藻有显著的抑制效果(P<0.05),6.00 g/L质量浓度组96 h时的F_v/F_m、Yield、α值抑制率分别达到99.87 %、100 %和100 %。综上所述,以植物落叶为原料研制针对刚毛藻的抑藻剂是可行的。     

Functional Properties of Dunaliella salina and Its Positive Effect on Probiotics

The unicellular green microalga Dunaliella is a potential source of a wide range of nutritionally important compounds applicable to the food industry. The aim of this study was to assess the effect of Dunaliella salina dried biomass on the growth and adherence of 10 strains of Lactobacillus, Lacticaseibacillus, and Bifidobacterium. The immunomodulatory, antioxidant, and cytotoxic effects of D. salina on human peripheral mononuclear cells and simulated intestinal epithelial cell lines Caco-2 and HT-29 were evaluated. Furthermore, the hypocholesterolemic effects of the microalgae on lipid metabolism in rats fed a high-fat diet were analyzed. The addition of D. salina biomass had a positive effect on the growth of nine out of 10 probiotics and promoted the adherence of three bifidobacteria strains to human cell lines. The antioxidant and immunomodulatory properties of D. salina were concentration-dependent. The inflammatory cytokines (TNF-α and IL-6) were significantly increased following Dunaliella stimulation at the lowest concentration (0.5% w/v). Eight week supplementation of D. salina to the diet of hypercholesteromic rats significantly decreased the serum concentrations of LDL-C, VLDL, IDL-B, and IDL-C. D. salina is not cytotoxic in intestinal cell models; it promotes adherence of selected bifidobacteria, it affords immunomodulatory and antioxidant effects, and its addition to diets may help decrease atherosclerosis risk factors.     

絮凝剂对藻类后续厌氧消化过程的影响

[目的]研究絮凝剂对藻类后续厌氧消化过程的影响。[方法]对不同含固率条件下水华藻类的产沼潜力及聚合氯化铝絮凝剂对藻类消化的影响进行分析。[结果]水华藻类的产甲烷潜力较高,含固率为6.0%时单位有机质累积甲烷产量可达147.03 mL/g VS,但脱水过程中使用的聚合氯化铝会严重抑制厌氧消化过程,在较低含固率3.0%条件下,铝离子浓度达984 mg/L,产气量低于潜力值的60%。[结论]该研究为藻类厌氧消化处理提供参考,同时为调整藻类采收方法提供理论依据。     

鸡粪厌氧消化废液的生物处理研究

应用好氧接触氧化，颤藻附着生物床和水生植物联合处理新工艺，对厌氧处理后的难生化降解的，碳氮磷比严重失调的鸡粪发酵液进行小规模的生产处理，经处理后出水可达ＧＢ８９７８－８８污水综合排放标准。颤藻为敝开处理系统中的优势藻种，固定在填料上的藻类去污能力强，脱氮，脱磷以及色素等效果好。充分进行光合作用，大量产生溶解氧能清洁水体。颤藻个大，易收集，定时采收后可作为畜用高蛋白饲料。     

库布齐沙漠东缘荒漠藻人工生物结皮的光谱特性简

为了探明库布齐沙漠东缘荒漠藻人工生物结皮的光谱特性,采用HR1024地物光谱仪,测定研究区包括荒漠藻在内的主要地物光谱数据,分析内蒙古林业科学研究院达拉特旗沙漠综合科学研究站不同年份接种的荒漠藻黑色、绿色结皮及裸沙、沙打旺、油蒿、沙柳的光谱特性及其变化规律.结果表明：1）沙打旺、油蒿、沙柳3种绿色植物光谱曲线与健康植被光谱曲线相近,“红边”位置明显,但荒漠藻黑色、绿色结皮及裸沙的光谱反射率变化比较平缓.2）荒漠藻绿色结皮表现出绿色植物所具有的光谱曲线变化特点;荒漠藻黑色结皮与绿色结皮光谱反射率相比,总的变化趋势为,在350～ 710 nm波段之间,黑色结皮光谱反射率较绿色结皮高,在710～1350nm波段之间,黑色比绿色结皮的光谱反射率低.     

基于CFD数值模拟的平板式微藻光生物反应器比较

为进一步提高微藻光生物反应器的混合与传质性能,在已有多节隔板平板式光生物反应器的基础上设计多级进气,新建立了多级进气多级隔板平板式光生物反应器。构建了普通反应器、多节隔板反应器、多级进气反应器并利用计算流体动力学模拟研究了3种反应器的流动与传质特性。结果表明,模拟结果与相关试验测量值吻合良好,多级进气结构可以带来更明显的级内环流现象,从而使该反应器在液体平均速度、死区比、湍动能、湍动能耗散率、气含率、液相传质系数等性能参数上较前2种反应器均有很大提高。在适合微藻培养的通气率0.4~0.8(每分钟通入反应器的气体体积与反应器实际装液体积之比)内,该反应器的混合及传质性能均表现优异。该工作为平板式生物反应器的设计及优化提供了新的方向。     

Beneficial effects of blue-green algae and Azolla, excluding supplying nitrogen, on wetland rice fields: a review

 The role of blue-green algae (BGA) and Azolla in supplying N to rice fields is well documented. In addition, they also bring about, directly or indirectly, a number of changes in the physical, chemical and biological properties of the soil and soil-water interface in rice fields. For example, BGA liberate extracellular organic compounds and photosynthetic O₂ during their growth, while Azolla prevent a rise in the pH, reduce water temperature, curb NH₃ volatilisation and suppress weeds; and both of them contribute biomass. On decomposing, they influence the redox activity and result in the formation of different organic acids in soil. All such changes brought about by BGA and Azolla in soil may ultimately influence plant-available nutrients and also soil characteristics. An attempt has been made in this review to highlight these effects of BGA and Azolla in rice fields and discuss their possible implications relating to management and productivity of rice-field systems. Received: 4 February 1998     

Use of blue-green algae and bryophyte biomass as a source of nitrogen for oil-seed rape

Summary Blue-green algal (Nostoc muscorum) or bryophyte (Barbula recurvirostra) growth on the surface of a brown earth silt loam contained in flooded columns significantly increased soil C (+20.9% and ±23.0%, respectively) and soil N (+25.1% and +9.6%, respectively) after 5 weeks in the surface 0.7-cm soil layer. Differences in the lower layers were not significant since there was no movement of C or N metabolites down the profile, even after 21 weeks. The input of C by the inoculated blue-green algae was estimated at 0.48 Mg C 100^-1 g soil or 0.45g C ha^-1; the bryophyte growth gave 0.5 Mg C ha^-1. N fixation by the blue-green algae alone was estimated at 60 kg N ha^-1 after 5 weeks of growth. Blue-green algae associated with bryophyte growth had fixed 23 kg N ha^-1 after 5 weeks, rising to 40 kg ha^-1 after 21 weeks. Decomposition of the bryophyte biomass led to a significant increase in the dry weight (+16.8%) and the N uptake (+27.5%) of spring oil-seed rape planted in homogenised soil. In contrast, soil incorporation of the blue-green algal biomass had no significant effect on yield. The equivalent mineralized N from the blue-green algal and bryophyte incorporation was estimated as 24 and 58 kg N ha^-1, respectively.     

Nitrogen use efficiency of microalgae application in wheat compared to mineral fertilizer

Background

Wastewater from sewage treatment plants contains high levels of nutrients, which can be used for plant nutrition. Classical wastewater treatment plants use complex microbial consortia of autotrophic and heterotrophic microorganisms for biological wastewater treatment. Certain autotrophic microalgae (e.g., species of the genera Chlorella, Scenedesmus, and Pediastrum) accumulate nutrients from wastewater very effectively.

Aims

We investigated the potential of microalgae biomass obtained from a prototype wastewater treatment plant as a source of nutrients for crops, focusing on nitrogen.

Methods

We provided wheat plants with different levels of algae biomass equivalent to 60, 120, and 180 kg N per hectare or with mineral fertilizer (N, P, and K) equivalent to the amounts contained in the algal biomass. Physiological and phenotypic traits were measured during growth, including vegetation indices, photosynthetic performance, growth, and nitrogen use efficiency (NUE). In addition, the adundances of Bacteria, Archaea and fungi and genes of ammonium oxidizing Bacteria and Archaea were determined in the rhizosphere of differently fertilized plants.

Results

Microalgal application at fertilizer levels of 120 and 180 kg N ha^–1 showed significantly improved physiological performance, growth, yield and nutrient uptake compared to the unfertilized control. Nevertheless, their yields and NUE were lower than with the application of equal amounts of mineral fertilization, while the adundance of rhizosphere microbes and ammonia-oxidizing microorganisms were not significantly affected.

Conclusions

Microalgae from wastewater treatments form a suitable source of organic fertilizer for wheat plants with only moderate reductions in N use efficiency compared to mineral fertilizer.