微藻培养的光生物反应器

微藻能有效利用光能、ＣＯ2 和无机盐类合成蛋白质、脂肪、碳水化合物以及多种高附加值生物活性物质 ,可以培养微藻来生产健康食品、食品添加剂、动物饲料、生物肥料及其他天然产品。另外 ,近年来分子遗传学和基因工程研究证实 ,大肠杆菌的载体和启动因子往往可以适用于蓝藻 ,尤其是单细胞蓝藻的转基因 ,这使得蓝藻基因工程得到了较快的发展 ,利用藻类为宿主的基因产物的生产也日益受到关注 ,因此微藻的培养受到广泛重视。微藻的生长方式决定光照在反应器中的重要性。除了一些能完全自养的微藻培养可以在无光照条件下进行[1](此时反应器可以…     

利用微藻生产生物柴油的研究进展

介绍了利用微藻生产生物柴油的优势及技术进展,对利用微藻生产生物柴油的经济性和可行性进行了分析和探讨,并指出了可以提高微藻柴油可行性的方法.     

微藻规模化培养技术研究进展

总结归纳了众多前人的研究成果,综述了微藻培养方式,并对规模化培养系统和主要的光生物反应器进行了简述。在此基础上,展望了微藻未来培养的发展方向,以期为今后微藻的规模化生产提供参考依据。     

微藻培养光生物反应器内传递现象的研究进展

微藻规模化培养过程中光生物反应器内传递现象是影响微藻的生长及产量的重要因素。本文重点综述了光生物反应器内传递现象（光传递、传热、传质和传动量传递）及其数学模型研究进展,分析了光生物反应器结构和尺寸对光传递和传质的影响,总结影响各传递现象的重要参数,如光吸收系数、体积传质系数等,为高效光生物反应器的设计、优化及放大提供了参考依据。     

光生物反应器中微藻生长影响因子研究进展

回顾了光生物反应器中微藻生长影响因子研究的总体情况,通过对其影响因子的系统分析得出,光照对微藻生长起着主要限制作用;二氧化碳、温度、营养盐及水动力特性对微藻生长影响较显著,各因子均存在一定的范围的适宜值能促进微藻生长;溶解氧和pH等因子也对微藻生长有一定影响,但其作用程度相对上述因子较低。目前研究所存在的问题有:1相关影响因子对微藻生长影响的内在机理和定量描述尚不完全;2各影响因子间均存在着一定的内在联系与相互作用,目前所展开的综合研究较少;3缺乏对光生物反应器制作材料的优化筛选及其与微藻生长影响的关系。     

光生物反应器中微藻生长影响因子研究进展

回顾了光生物反应器中微藻生长影响因子研究的总体情况,通过对其影响因子的系统分析得出,光照对微藻生长起着主要限制作用;二氧化碳、温度、营养盐及水动力特性对微藻生长影响较显著,各因子均存在一定的范围的适宜值能促进微藻生长;溶解氧和pH等因子也对微藻生长有一定影响,但其作用程度相对上述因子较低。目前研究所存在的问题有:1相关影响因子对微藻生长影响的内在机理和定量描述尚不完全;2各影响因子间均存在着一定的内在联系与相互作用,目前所展开的综合研究较少;3缺乏对光生物反应器制作材料的优化筛选及其与微藻生长影响的关系。     

微藻光生物反应器应用研究

选择三种海洋微型藻,叉鞭金藻、扁藻和塔玛亚历山大藻,在自行研制的光生物反应器中进行人工培育繁殖,采用不同光照强度和搅拌速度,测试光生物反应器应用于海洋微藻人工培育的效果。研究结果表明:这三种海洋微型藻在研制的生物反应器中细胞均能快速分裂增长,细胞增殖的浓度比在自然条件培养的同种藻的细胞增殖浓度要高1-2倍。并验证该光生物反应器的光照强度和搅拌强度可以根据微藻实际生长需要而调整到最佳状态,扁藻、叉鞭金藻、塔玛亚历山大藻分别在光照强度10000Lx±300Lx、5000Lx±300Lx、3000Lx±300Lx时生长最好。高转速和连续搅拌不利于塔玛亚历山大藻细胞增殖,增殖慢、藻浓度不高。     

用于微藻培养的气升式光生物反应器

基于微藻光自养培养特性 ,构建了具有较大面积体积比的 15 L内外光源相结合的气升式光生物反应器 ,考察了两种不同形态藻细胞培养体系中 ,光强随细胞浓度及光程距离衰减的规律 ,得到了描述光衰减的数学关系式 ,即在鱼腥藻 712 0培养体系中为 I=I0 exp[- (0 .0 131+0 .987OD750 )·L],在聚球藻 70 0 2培养体系中为 I=I0 exp[- (- 0 .0 2 39+0 .0 777OD750 )·L],并据此对培养过程中光强沿反应器径向的动态分布情况进行了估算。在该反应器中进行了鱼腥藻 712 0和聚球藻 70 0 2两种蓝藻的光自养培养 ,藻细胞培养终密度分别达到 1.5 3g/ L和 3.4g/ L ,体积产率分别为 0 .31g L-1d-1和 0 .5 7g L-1d-1,说明该反应器适合于微藻的高密度培养     

微流体技术在微藻生物柴油中的应用进展

聚焦于微流体技术在微藻生物柴油中的应用,归纳了限制微藻生物柴油商业化的技术障碍,重点介绍了微流体技术在产油微藻的筛选、鉴定、培养、采收、浓缩、脂质提取以及微藻原位酯交换中的应用进展,讨论了微流体装置在微藻生物柴油中发挥的作用,最后提出了微流体技术在微藻生物柴油应用中面临的问题并展望了其应用前景。     

光生物反应器微藻生长与比消光系数的关系

研究了两种微藻液消光系数的波长分布特征。经分析发现,色素吸收消光占总消光的比例各个波长下均小于１／４。藻体颗粒大小是藻液比消光系数的重要决定因素。利用这一特性可以监测单细胞藻的同步生长。文中指出：当入射光强相同,且在相同几何尺寸的光生物反应器中培养微藻,藻体半径越大,藻液的比消光系数越小藻液的平均光强越高。     

Microbial community in seawater reverse osmosis and rapid diagnosis of membrane biofouling

Due to the acceleration of global warming and the stress that population growth has placed on the global water supply, seawater reverse osmosis (SWRO) desalination is arising as a promising technology to overcome the stress placed on current water resources. However, the biofouling of RO membranes is a common problem, as it causes flux decline, demands frequent cleanings, and consumes high energy, resulting in a shortened lifespan of the system. In an attempt to address these issues, detailed knowledge of the microbial bacteria present, which have a strong correlation between biofilm community structure and operational problems, is ultimately expected to lead to greater control of biofouling. Furthermore, a more rapid diagnosis of biofilm bacteria in SWRO processes is required for faster process feedback. In this study, previous approaches that have been proposed for understanding, diagnosing, and predicting biofouling are reviewed. Finally, the future outlook towards controlling biofouling in SWRO is discussed.     

Effect of biofouling on corrosion behaviour of grade 2 titanium in Mandapam seawaters

Titanium has the ability to withstand extremely high seawater velocities with negligible corrosion. The inherent passive nature of the metal favours the attachment of bio-organisms more. In this paper the biofouling characteristics and the influence of macrofouling on grade 2 titanium have been investigated in the Palk Bay waters of Mandapam (India) over a period of a year.This work comprises both field exposure as well as laboratory studies. The deposits on titanium were analyzed with the XRD technique. Green algae such as Cladophorapsis zoolengeri, Cheatomorpha area, Chlorodesmis hillibrandii, Enteromorpha intestinalis, Cladophora species and red algae species of Hypnea valentiae, and animals such as bryozoans and barnacles 4 mm in size were identified on the titanium metal surface. The effect of macrofouling on corrosion of titanium was investigated by both impedance and polarization techniques. Titanium experienced negligible corrosion in seawater exposure with an appreciable fouling load of 0.4527 kg.m⁻²y⁻¹.     

无定型玻璃态聚碳酸酯的塑性行为模拟

用常压分子动力学模拟和固定晶胞能量最小化计算程序,以及构型和能量分析研究了无定型玻璃态聚合物双酚—A—聚碳酸酯(BPA-PC)的塑性变形。计算结果和"势能面理论"架构吻合,此理论将塑性转换解释成"理想结构"之间的相互交叉和塌陷。本方法可以在晶胞尺度有限、高压缩比和低温下对聚合物材料进行模拟,密度、杨氏模量、屈服应变、屈服应力、激化能、激化体积都与BPA-PC的实验数据吻合。     

Effect of dechlorination point location and residual chlorine on biofouling in a seawater reverse osmosis plant

Experiments were carried out to test the effect of dechlorination dosing point location and the concentration of residual chlorine on bacterial growth and biofouling in a seawater reverse osmosis (SWRO) plant. The plant is located in Al-Birk on the Red Sea coast, southern Saudi Arabia. The plant was routinely operated with injection of chlorine as a biocide in the intake chamber in the open sea and with the injection of sodium metabisulfite (SBS) to remove chlorine after the dual media filter (DMF). During the experiments, the SBS dosing point was shifted to two locations after the micron cartridge filter (MCF): first, to a point 13 m ahead of the high pressure pump (HPP) and second, to a point just ahead (<1 m) of the HPP. Due to fluctuations in residual chlorine resulting from certain operational and physical circumstances, it was possible to assess biofouling potential when free chlorine is regarded as high (≥0.5 mg/l) or low (<0.5 mg/l) within a maximum of 1 mg/l. Bacterial generation (doubling) time was used to evaluate biofouling. Generation time was higher (lower multiplication capacity) when the SBS dosing point was before the MCF (after DMF). It decreased significantly, reflecting higher multiplication capacity and higher biofouling potential, when the SBS dosing point was moved to after the MCF. Generation times in high-pressure RO feed water were similar when the SBS dosing point was moved to two locations after the MCF. This indicated minimal contribution of the low-pressure pipe between the MCF and the HPP to biofouling. In general, biofouling increased as the SBS dosing point was moved forward along the pretreatment line, closer to the RO membranes. Generation times were similar when residual chlorine was less or more than 0.5 mg/l. Bacteria were capable of biofilm formation in the chlorinated section of the plant.     

Nanoindentation behavior of ultrathin polymeric films

Measurement of the mechanical properties of nanoscale polymeric films is important for the fabrication and design of nanoscale layered materials. Nanoindentation was used to study the viscoelastic deformation of low modulus, ultrathin polymeric films with thicknesses of 47, 125 and 3000 nm on a high modulus substrate. The nominal reduced contact modulus increases with the indentation load and penetration depth due to the effect of substrate, which is quantitatively in agreement with an elastic contact model. The flow of the nanoscale films subjected to constant indentation loads is shear-thinning and can be described by a linear relation between the indentation depth and time with the stress exponent of 1/2.     

Comparison of glassy carbon and boron doped diamond electrodes: Resistance to biofouling

Carbon based electrodes are widely used for in vivo and in vitro electrochemical studies. In particular, monoamine neurochemistry has been investigated using carbon microfibre electrodes. Similarly, glassy carbon (GC) is the preferred material for many biochemical applications, such as electrochemical detection in chromatography. More recently, boron doped diamond (BDD) has been utilized for biosensing, as its carbon sp³ structure is expected to provide better resistance to analyte fouling. However, the main factor limiting the use of electrochemical sensors for biological studies is the effect of the biological matrix. Indeed, in vivo or in situ measurements expose the sensor to a complex matrix of proteins, which adsorb on the sensing surface and interfere with the electrochemical measurements.Here, we compare the performance of three carbon based electrodes: GC, GC with low surface oxides and BDD. The redox species ruthenium(III) hexaammine (outer-sphere), ferrocyanide (surface sensitive) and the biologically significant dopamine have been investigated in protein and blood-mimicking matrices. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to examine the effect of spectator molecules and reaction products on electrode mechanisms.Our results show that BDD generally exhibits the best performance for most conditions and reactions and should therefore be preferred for measurements in biologically fouling environments. Furthermore, surface oxides seem also to improve resistance of the GC electrode to biofouling.     

Effect of surface free energy on the adhesion of biofouling and crystalline fouling

Pipelines and heat exchangers using seawater as coolant suffer from biofouling. Biofouling not only reduces heat transfer performance significantly, but also causes considerable pressure drop, calling for higher pumping requirements. It would be much more desirable if surfaces with an inherently lower stickability for biofouling could be developed. In this paper, a cost-effective autocatalytic graded Ni-Cu-P-PTFE composite coating with corrosion-resistant properties was applied to reduce biofouling formation. The experimental results showed that the surface free energy of the Ni-Cu-P-PTFE coatings, which were altered by changing the PTFE content in the coatings, had a significant influence on the adhesion of microbial and mineral deposits. The Ni-Cu-P-PTFE coatings with defined surface free energy reduced the adhesion of these deposits significantly. The anti-bacterial mechanism of the composite coatings was explained with the extended DLVO theory.