在光生物反应器培养螺旋藻中pH值的调控作用分析

在光辐射板式光生物反应器中 ,为实现螺旋藻单藻种群优势生长 ,分析研究了螺旋藻在光生物反应器培养过程中 ,pH值的调控作用。研究结果表明 ,溶液的 pH值不仅显著影响培养基中无机碳源营养基质的离解程度 ,螺旋藻的光合放氧特性 ,而且是控制螺旋藻优势单种培养的必要条件和关键因素 ,当溶液的 pH值控制在 9 0～ 9 5时 ,即使螺旋藻处于低温或营养限制性生长时 ,仍能实现优势单藻种生长     

光生物反应器内设LED光源的特性研究

从LED集成光电板的光电特性、光热效应、光衰减性、光辐射特征与植物和藻类光吸收特征的相匹配性及LED辐射单色光对螺旋藻的光合色素含量的影响等几方面 ,分析研究了LED集成光电板作为光生物反应器内部光源的特性及可行性 ,研究结果表明 ,LED集成光电板作为光生物反应器的内部光源 ,它所发射的单色光谱红光 (6 6 0～ 6 80nm、蓝光 (430～4 50nm) ,不仅能覆盖植物和藻类光合作用所需要吸收的光谱能带 ,促进叶绿素a对光能的吸收和螺旋藻的生长 ,增强光合作用 ,使细胞生物量与光合色素含量显著提高 ;而且不被吸收的光谱减少 ,节能达 38 75% ,无疑它将是光生物反应器潜在最有效的光源     

高效培养螺旋藻封闭式光生物反应器系统的结构单元分析

本文根据螺旋藻工业生产特点和现状及国内外研究动态分析表明，螺旋藻等藻类生物高新技术的产业发展潜力，在很大程度上主要取决于封密式光生物反应器技术的发展。目前，封密式新型光生物反应器的研制已成为螺旋藻大规模培养及基因工程藻类生物工程技术的主要发展趋势及国外研究热点，而在我国，此项研究则刚刚起步。本文通过分析国外研制的光生物反应器系统的结构单元，阐述在这一研究领域的设计思路，主要问题及发展方向。     

螺旋藻的光生物反应器高密度培养

利用自制的光生物反应器对螺旋藻的生长进行了研究。结果表明 :光照强度和液体循环速度对藻体细胞的生长有极显著的影响 ,培养温度对生长有显著的影响 ;通过流加和碳源的供给形式的改变等培养条件和培养工艺的改进使藻体的生长速率、生物量产率和生物量产量分别达到了 0 .4 1 1 /d、3 2 .2 5g/m2 · d和 3 .93 g/L的水平 ,最大生长速率达到了0 .566/d。     

微藻培养中光生物反应器的研究进展

研制和应用光生物反应器是实现微藻的高密度和规模化培养的重要技术。本文综述了近年来微藻培养中光生物反应器的类型、基本构造以及实际应用状况,并对反应器的控制操作系统及检测技术做了简单的介绍,为微藻的高密度培养提供一些参考。     

采用不同装置培养螺旋藻的对比研究

该试验在光合自养和混合营养两种条件下,分别采用250 mL摇瓶、5.0 L全自动发酵罐和10.0 L自制光生物反应器培养螺旋藻,以藻体生物量为试验指标,比较细胞在3种装置中的生长情况。结果可知,10.0 L光生物反应器培养效果最好,在光合自养条件下藻体生物量最大为1.277 g/L,比摇瓶和全自动发酵罐培养时分别提高78.6%和61.8%,混合营养条件下最大值为1.715 g/L,比其他两种装置分别提高了6.3%和6.1%。表明自制的光生物反应器能很好地满足螺旋藻细胞生长,且结构简单,操作简便。     

Improvement of growth stability of photosynthetic bacterium Rhodobacter capsulatus

Using a semicontinuous culture method, in which operational parameters such as cell concentration and light intensity distribution were maintained almost constant, instability of the specific growth rate of Rhodobacter capsulatus B-100, a purple bacterium, was observed to be similar to that of R. capsulatus ST-410 when cultivated under high ratios of light intensity on the illuminated side to that of the transmitted light. Such instability was not observed in the cultivation of Chlorella vulgaris, a eukaryotic green alga, even at higher cell concentrations. Under the same conditions, the increase in only the ferrous concentration from 43 microM, the concentration in the original RCV medium, to 172 microM sustained a stable growth, whereas Fe(2+) was slightly consumed during the cultivation. Supplemental illumination with a fluorescent lamp on the transmitted side of a flat plate photobioreactor sustained a moderate level of stable growth, while a halogen lamp slightly affected the growth stability. Our results showed that an increase in Fe(2+) concentration or supplemental illumination improves the growth stability of R. capsulatus.     

采用新型溢流喷射光生物反应器培养螺旋藻的研究

采用一种新型溢流喷射光生物反应器进行螺旋藻的室内分批培养试验。并使用溢流喷射器同时实现藻液的循环、搅拌和通气。     

Quantitative measurement of direct nitrous oxide emissions from microalgae cultivation

Although numerous lifecycle assessments (LCA) of microalgae-based biofuels have suggested net reductions of greenhouse gas emissions, limited experimental data exist on direct emissions from microalgae cultivation systems. For example, nitrous oxide (N(2)O) is a potent greenhouse gas that has been detected from microalgae cultivation. However, little quantitative experimental data exist on direct N(2)O emissions from microalgae cultivation, which has inhibited LCA performed to date. In this study, microalgae species Nannochloropsis salina was cultivated with diurnal light-dark cycling using a nitrate nitrogen source. Gaseous N(2)O emissions were quantitatively measured using Fourier transform infrared spectrometry. Under a nitrogen headspace (photobioreactor simulation), the reactors exhibited elevated N(2)O emissions during dark periods, and reduced N(2)O emissions during light periods. Under air headspace conditions (open pond simulation), N(2)O emissions were negligible during both light and dark periods. Results show that N(2)O production was induced by anoxic conditions when nitrate was present, suggesting that N(2)O was produced by denitrifying bacteria within the culture. The presence of denitrifying bacteria was verified through PCR-based detection of norB genes and antibiotic treatments, the latter of which substantially reduced N(2)O emissions. Application of these results to LCA and strategies for growth management to reduce N(2)O emissions are discussed.     

大规模封闭式光生物反应器培养小球藻效果试验

在海南室外进行吨级光生物反应器中培养小球藻试验。当地藻种最高藻细胞密度达到27.45×107cell/mL,每天采收培养水体30%,平均日产量达到0.378 g/L.d细胞干重。北方藻种最高藻细胞密度达到3.38×107cell/mL,细胞干重达到1.44 g/L.d。     

无机碳源和有机碳源的相对含量和相互作用对螺旋藻混合营养生长的影响

在螺旋藻的混合营养生长中，若HCO3－浓度低（如0．05mol／L），螺旋藻优先同化葡萄糖时产生的一些有机副产物对其生长会产生抑制作用；而HCO3－浓度高时（如0．2mol／L），该抑制作用会减轻。自养生长条件下，在非开放的光生物反应器中，只要藻种未被污染，可采用0．05mol／LHCO3－培养螺旋藻而不会影响其生长。     

Advanced control for photoautotrophic growth and CO2-utilization efficiency using a membrane carbonation photobioreactor (MCPBR)

A membrane carbonation (MC) module uses bubbleless gas-transfer membranes to supply inorganic carbon (C(i)) for photoautotrophic cyanobacterial growth in a photobioreactor (PBR); this creates the novel MCPBR system, which allows precise control of the CO(2)-delivery rate and minimal loss of CO(2) to the atmosphere. Experiments controlled the supply rate of C(i) to the main PBR by regulating the recirculation rate (Q(R)) between the module of MC chamber and the main PBR. The experiments evaluated how Q(R) controls the CO(2) mass transport in MC chamber and how it connects with the biomass production rate, C(i) concentration, pH in the PBR, and CO(2)-utilization efficiency. The biomass production rate and C(i) concentration increased in response to the C(i) supply rate (controlled by Q(R)), but not in linear proportion. The biomass production rate increased less than C(i) due to increased light limitation. Except for the highest Q(R), when the higher C(i) concentration caused the pH to decrease, CO(2) loss to gas ventilation was negligible. The results demonstrate that this MCPBR offers independent control over the growth of photoautotrophic biomass, pH control, and minimal loss of CO(2) to the atmosphere.     

紫球藻的培养及其硫酸多糖的分离纯化

利用优化了的海水培养基和简易光生物反应器对紫球藻进行培养,建立了一套从培养液中直接分离纯化紫球藻多糖(PSP)的工艺,并对纯化后的PSP进行了初步分析。实验表明,本方法培养的紫球藻生物量达到了干重2.1g/L,分离后粗PSP产量为0.378g/L,离子交换得率约为78%。经气相色谱分析PSP主要由木糖、葡萄糖和半乳糖组成,质量比约为13.68:7.83:5.23。红外光谱显示该多糖具有一般多糖的特征吸收峰,其中六碳糖为吡喃型。PSP为硫酸酯化多糖,硫酸基团含量约为4%。     

Growth and hydrocarbon production of microalga Botryococcus braunii in bubble column photobioreactors

Microalga Botryococcus braunii, which produces high levels of liquid hydrocarbons called botryococcenes, was cultivated in bubble column photobioreactors. Algal cells, adapted to low irradiance (3 klx) in the preculture, showed lower biomass and hydrocarbons productivity in the photobioreactor illuminated at high irradiance (10 klx) due to the effects of photoinhibition. The degree of photoinhibition was reduced by partial shading, the lighted volume ratio being varied from 25 to 100%. The algal cells adapted to high irradiance in the preculture showed a high biomass productivity at 10 klx: the cell concentration reached higher than 7 kg/m³ and the hydrocarbon content was 50% based on cell dry weight. Hydrocarbon production kinetics of this alga in the linear growth phase was found to be growth-associated irrespective of the experimental conditions of illumination and preculture.     

Growth and hydrocarbon production of microalga Botryococcus braunii in bubble column photobioreactors

Microalga Botryococcus braunii, which produces high levels of liquid hydrocarbons called botryococcenes, was cultivated in bubble column photobioreactors. Algal cells, adapted to low irradiance (3 klx) in the preculture, showed lower biomass and hydrocarbons productivity in the photobioreactor illuminated at high irradiance (10 klx) due to the effects of photoinhibition. The degree of photoinhibition was reduced by partial shading, the lighted volume ratio being varied from 25 to 100%. The algal cells adapted to high irradiance in the preculture showed a high biomass productivity at 10 klx: the cell concentration reached higher than 7 kg/m3 and the hydrocarbon content was 50% based on cell dry weight. Hydrocarbon production kinetics of this alga in the linear growth phase was found to be growth-associated irrespective of the experimental conditions of illumination and preculture.     

Continuous cultivation of <Emphasis Type="Italic">Dunaliella salina</Emphasis> in photobioreactor for the production of β-carotene

A helix tube photobioreactor with a volume of 10 L was designed and manufactured. The facade of the reactor was designed as three-layer frame. The illumination helixes units were 16, illumination area volume was 1.5 L, illuminate specific area was 95 m⁻¹. A marine micro-alga Dunaliella salina was used as a model organism in this study. Results showed that the optimum inoculum concentration was OD₆₃₀ = 0.15 and the optimum circulation rate of culture fluid was 630 mL/h for the bioreactor. In continuous cultivation, in order to determine the optimum collection of alga solution for the highest yield of β-carotene, three different alga solution collection and addition fresh culture medium volumes were applied: 0.8, 1.5, 2.0 L/day. The biomass and extraction of β-carotene were determined in different cultivation periods. The result suggested that the optimum daily harvest of alga solution was 1.5 L/day for the cultivation of D. salina to obtain the highest production of β-carotene.     

Combinatorial life cycle assessment to inform process design of industrial production of algal biodiesel

The use of algae as a feedstock for biodiesel production is a rapidly growing industry, in the United States and globally. A life cycle assessment (LCA) is presented that compares various methods, either proposed or under development, for algal biodiesel to inform the most promising pathways for sustainable full-scale production. For this analysis, the system is divided into five distinct process steps: (1) microalgae cultivation, (2) harvesting and/or dewatering, (3) lipid extraction, (4) conversion (transesterification) into biodiesel, and (5) byproduct management. A number of technology options are considered for each process step and various technology combinations are assessed for their life cycle environmental impacts. The optimal option for each process step is selected yielding a best case scenario, comprised of a flat panel enclosed photobioreactor and direct transesterification of algal cells with supercritical methanol. For a functional unit of 10 GJ biodiesel, the best case production system yields a cumulative energy demand savings of more than 65 GJ, reduces water consumption by 585 m(3) and decreases greenhouse gas emissions by 86% compared to a base case scenario typical of early industrial practices, highlighting the importance of technological innovation in algae processing and providing guidance on promising production pathways.     

白光和红光光周期对西兰花芽苗菜生理生化和萝卜硫苷代谢的影响

本文研究了白光和红光不同光周期（0、4、8、12、16和20 h·d?1）对西兰花芽苗菜生长、可溶性糖、可溶性蛋白、抗坏血酸、花色苷和萝卜硫苷代谢的影响。结果表明:光照抑制西兰花芽苗的生长,红光较白光处理能够促进西兰花芽苗芽长增长;随着光周期的延长,西兰花芽苗菜中可溶性糖、可溶性蛋白、抗坏血酸、萝卜硫苷和总硫苷含量、黑芥子酶活力以及萝卜硫素含量均呈现先增加后降低的趋势。相较于白光,红光明显提高了西兰花芽苗菜中可溶性糖、可溶性蛋白、抗坏血酸和萝卜硫苷含量。但白光处理下花色苷含量明显高于红光处理。在光周期小于12 h·d?1时,红光处理下萝卜硫素形成量显著高于白光处理（P<0.05）,而当光周期大于12 h·d?1时,红光处理下萝卜硫素形成与白光处理之间差异不显著甚至低于白光处理。总之,红光相较于白光更有利于提高西兰花芽苗菜的产量和营养品质,12 h·d?1是比较适合的光周期。     

A study of the photolightening mechanism of blond hair with visible and ultraviolet light

In this study the photolightening behavior of blond hair was investigated. The results demonstrated that visible (VIS) and ultraviolet (UV) light lighten blond hair through different mechanisms. VIS light was found to contribute much more to the lightening of blond hair than UV light, and acted directly, while UV light only lightened blond hair that had been washed following irradiation. VIS and UV light both, however, lightened to a similar degree isolated melanin granules and decomposed melanin granules that were exposed on a cross section of blond hair. These results indicate that melanin granules are equally sensitive to both forms of light while blond hair is most sensitive to VIS light. The results also indicate that hair tissues, excluding melanin granules, are damaged by UV light but not by VIS light. Based on these facts, the hypothetical lightening mechanism of UV light is assumed to be that UV light preferentially attacks and damages hair tissues rather than melanin granules. This occurs only after the hair is washed, as the washing process removes the melanin granules that effuse from loose hair fibers. In contrast, VIS light preferentially attacks and decomposes the melanin granules rather than other tissues, and also results in the lightening of blond hair but without the need for subsequent washing. We also found that while VIS light destroys the structure of isolated melanin granules, UV light does not act in a similar manner. Consequently, it is proven that VIS and UV light attack different sites of the melanin granule, even though the lightening rates from both light sources are similar.     

转光膜的制备及性能研究

为了研究转光膜的光学特性和机械性能,将两种不同的转光剂(A、B)添加到聚乙烯树脂中,采用母料法制备转光膜.通过测试转光膜的荧光光谱和机械性能,得出以下结论:与普通薄膜相比,转光膜有明显的转光效果;添加转光剂A制备的薄膜转光效果较好;添加少量的转光剂对薄膜的机械性能影响不大.