微藻固碳技术基础及其生物质应用研究进展

简要综述了近年来国内外微藻固定二氧化碳的研究进展,着重讨论了光照、温度、pH和营养成分对微藻固碳生长的影响。从光生物反应器的结构、光的供给、混合与传质入手,合理设计反应器来提高效率。探讨了微藻固碳后的采集及其潜在的应用,破解长期存在于经济发展和二氧化碳排放之间的矛盾,对微藻的应用研究有所启示。     

小球藻光生物反应器设计及其应用

小球藻属于单细胞藻类,在地球上出现得非常早,因为它含有丰富的脂质、蛋白质、食用纤维,且有抗病毒感染、抗病原菌等活性,一直受到人们的关注。微藻太阳能运用个体小、生长迅速、效率高且易培养,所以人们很重视微藻开发工作,并在医药制品、食品保健等领域得到广泛应用。论述了光生物反应器种类和特点、光生物反应器的性能影响因素,进而设计出一种价格低廉、操作简单的罐式光生物反应器;介绍了光生物反应器在煤化工废水处理方面的运用。     

光生物反应器对工业锅炉烟道尾气中二氧化碳的利用

比较了工业化光生物反应器培养微藻的3种主要CO2利用方式,阐述了工业锅炉烟道尾气所含多种重金属元素会在藻液中形成重金属离子,微藻在吸收CO2的同时也吸附重金属离子的机理.指出当重金属离子在藻液中积累到一定浓度时会造成光生物反应器的微藻生长系统崩溃,不能直接采用工业锅炉烟道尾气作为工业化封闭式光生物反应器培养微藻系统的碳源供给方式.     

海洋微藻培养及光生物反应器的研究进展

概述微藻的特点及国内外应用现状,重点讨论培养微藻的条件及不同类型光生物反应器的特点。     

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。     

套管式新型光生物反应器的性能初步实验

针对管式光生物反应器藻液中溶解氧及pH限制进一步规模扩大等因素,设计了一种套管新型内曝气式光生物反应器。以Chlorella vulgaris为培养对象,BG-11为培养基,以细胞干重为检测指标,同时检测藻液的溶氧量和pH,比较了小规模实验条件(锥形瓶,500 mL)和套管式新型光生物反应器(36 L)对微藻生物质积累的影响。结果表明,新型反应器和小规模实验条件相比,培养体积扩大了72倍,培养10 d时微藻的比生长率下降了33.2%,单位体积产率下降了69.8%。在整个培养过程中,藻液溶氧量为6.2～7.0 mg/L,未超过限值7.5 mg/L。通入气体为空气,藻液pH由7.5上升至9.0,处于微藻可适应范围(4.5～10.6),尚可通过在空气中混入CO2进行调节。     

立式管排式微藻光生物反应器的设计及应用

微藻生物能源作为一种清洁可再生能源,具有较好的应用前景,但现有光生物反应器的低效率、高成本制约了微藻生物能源的发展。以提高光生物反应器生物质产率、降低制造和运营成本为目标,设计了一种管排式光生物反应器,并进行了小试和中试试验。从固定成本投入和生物质产率方面评价了该反应器的性能,结果表明：立式管排式光生物反应器较传统的管道式反应器具有显著的优势,单位面积产率达到30 g/(m²·d),较传统的管道式反应器提高了4倍。在相同的培养体积下,立式管排式反应器比管道式反应器占地面积减少了66%,设备投入减少了31%,能耗成本降低了75%。     

微藻生物固碳法在煤电碳减排应用的研究进展

概述了煤电碳排放及烟气碳减排技术发展现状,从藻种选育、光反应器开发、产业化模式探索三方面阐述了微藻固碳技术的研究进展,分析对比了平板式、管式、垂直柱式光生物反应器的工程化应用的适用性,进一步探讨了耦合烟气减排、污水处理、微藻能源和藻体大宗产品的微藻商业化减排模式,展望微藻固碳在煤电减排工程化应用中广阔的前景。     

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。     

Mathematical modelling of light dependent microorganisms cultivation in countercurrent film reactor

The kinetic parameters of the pseudo-continuous cultivation of green microalgae in the film photobioreactor with countercurrent flows of gas and liquid phases and equipped with spirals on the internal surface of quartz tubes have ben studied. A mathematical model of mass transfer during microalgae cultivation in a film photobioreactor has been developed. The model includes a kinetic equation that considers the effect of the conditions of the cultivation of microalgae populations and cells interactions. A method has been developed for solving equations of the model that uses the Galerkin combination and the finite-element methods.     

Characterization of a Novel Flat‐Panel Airlift Photobioreactor With an Internal Heat Exchanger

A novel flat‐panel airlift photobioreactor with an internal heat exchanger (FPA‐IHE) separating the riser and downcomer zones was characterized. The proposed FPA‐IHE has working volume of 2.2 L, height of 450 mm and light path of 50 mm. The overall heat transfer coefficients for the internal heat exchanger and the external surface of the reactor were 47.0 W m^–2K^–1 and 7.1 W m^–2K^–1, respectively. The mass transfer coefficient increased with an increase in the volumetric power input until a value of 0.01 s^–1. The mixture time decreased with the increase in the superficial gas velocity of the riser. The circulation time ranged from 5 to 6 s. The specific growth rates of Dunaliella tertiolecta and Chlorella minutissima were high, 0.77 d^–1 and 0.67 d^–1, respectively; thus, the FPA‐IHE photobioreactor is a promising environment for the development of highly productive processes using microalgae.     

Advances in photobioreactors for intensive microalgal production: configurations,operating strategies and applications

Over the past ten years a great deal of literature has focused on the biotechnological potential of microalgal commercial applications, mainly in the field of biofuel production. However, the biofuel production is not yet competitive, mainly due to the incidence of the photobioreactor technology on the process cost. Besides, major advances in classic photobioreactor design, several novel configurations have been proposed in the last 20 years to improve their performance expressed in terms of light absorption, biomass productivity, light to biomass yield and photosynthetic efficiency. This review aims at analyzing and classifying the most recent advances and the several novel approaches to the design, development, control and modeling of photobioreactors. The diverse approaches are grouped considering irradiance strategies, multiphase hydrodynamics, mass transfer mechanisms, modeling approaches and control strategies. Some innovative applications of the photobioreactor technology are also reported. © 2013 Society of Chemical Industry     

一种新型多节隔板-平板式光生物反应器的数值和实验研究

光是影响光生物反应器培养效率的最主要因素之一.而在一定的外部光强下,光生物反应器内部的混合状况对微藻细胞生长有重要影响.采用CFD(Computational Fluid Dynamics)模型对一种新型多节隔板-平板式光生物反应器在不同通气量下的流场分布进行了模拟并与PIV(Particle Image Veloeimetry)测量结果进行比较,结果表明CFD模型可用于光生物反应器流场的模拟;利用CFD模型对不同隔板节数的平板式光生物反应器的内部流场进行了模拟,对光照方向混合进行定量研究,并通过分析光照方向径向速度U、下降通道体积平均湍动能ADT、流体(藻液)绕隔板循环一周所用时间tc、下降通道(光区)停留时间占藻液绕隔板循环一周所用时间的比例ε四个参数来优化光生物反应器的隔板节数.理论分析表明,三节隔板-平板式光生物反应器为最佳选择,并通过球等鞭金藻3011培养实验对此进行了验证.     

Modified Photobioreactor for Biofixation of Carbon Dioxide by Chlorella vulgaris at Different Light Intensities

The performance of a modified bioreactor inside a light enclosure for carbon dioxide biofixation by Chlorella vulgaris was investigated. The influence of different light intensities on the CO₂ biofixation and biomass production rates was evaluated. The results showed that the photon flux available to the microalgal cultures can be a key issue in optimizing the microalgae photobioreactor performance, particularly at high cell concentrations. Although the optimal pH values for C. vulgaris are in the range of 6–8, cell growth can take place even at pH 4 and 10. Batch microalgae cultivation in the photobioreactor was used to investigate the effect of different light intensities. The maximum biomass concentration of 1.83 g L^?1 was obtained at a light intensity of 100 μmol m^?2s^?1 and under aeration with 2 L min^?1 of 2 % CO₂‐enriched air.     

Split internal-loop photobioreactor for Scenedesmus sp. microalgae:Culturing and hydrodynamics

In this study, the evaluation of the performance of the split internal loop photobioreactor for culturing a species of green microalgae, Scenedesmus sp. under different operating superficial gas velocity and during a different time of growth (i.e., starting for the first day until end day of the culturing process) was addressed. The evaluation of the performance of the split internal loop photobioreactor was included assessing the density, pH, temperature, vis-cosity, surface tension, the optical density, cell population, dry biomass, and chlorophyll of the culture medium of the microalgae culturing. Additionally, the hydrodynamics of a Split Internal-Loop Photobioreactor with microalgae culturing was comprehensively quantified. Radioactive particle tracking (RPT) and gamma-ray com-puted tomography (CT) techniques were applied for the first time to quantify and address the influence of microalgae culture on the hydrodynamic parameters. The hydrodynamics parameters such as local liquid veloc-ity field, shear stresses, turbulent kinetic energy, and local gas holdup profiles were measured at different super-ficial gas velocities as well as under different times of algae growth. The obtained results indicate that the flow distribution may significantly affect the performance of the photobioreactor, which may have substantial effects on the cultivation process. The obtained experimental data can serve as benchmark data for the evaluation and validation of computational fluid dynamics (CFD) codes and their closures. This, in turn, allows us to develop ef-ficient reactors and consequently improving the productivity and selectivity of these photobioreactors.     

微藻柱状式光生物反应器流动特性及结构的数值模拟优化

微藻作为最具潜力的可再生生物质能源,在生物固碳和生物燃料生产领域优势显著,有助于碳达峰、碳中和目标的实现。通过改善反应器曝气装置的性能可以大幅度提高微藻的培养效率,本工作采用数值模拟方法对柱式光生物反应器的球型曝气结构进行了优化。模拟采用欧拉模型,湍流模型选取k-ε模型,研究分析了不同曝气装置条件下气含率、平均液相速度、湍流动能几种参数的变化和光生物反应器内的流场情况。结果表明,曝气装置结构的变化对光生物反应器内的流动特性具有很大的影响,通过曝气装置向反应器内通气,气含率、平均液相速度、湍流动能随着曝气量的增大而增大,随着曝气装置孔径的增大而减小。综合各相关参数得到当总曝气量为1400 mL/min、曝气孔数为50、曝气孔径为30μm时,曝气装置性能最好,此时测得气含率为68.6%,平均液相速度为0.905 m/s,湍流动能为0.149 m²/s²。     

转基因聚球藻7942培养中光传递及其对细胞生长的影响

对转人源胸腺素a1基因聚球藻7942光生物反应器分批培养过程中光的分布、平均光强变化及其对藻细胞生长的影响进行了分析. 结果表明，Hyperbolic光衰减模型较之Lambert-Beer光衰减模型能更好地描述转基因聚球藻7942培养液中的光衰减；随着藻细胞密度的增加，光生物反应器内平均光强不断减小，藻细胞的光能比吸收速率也不断降低，反应器中“暗区”体积不断加大；培养时间0~1.5 d，藻细胞能获得充足光能，因而呈指数生长；1.5 d后藻细胞处于光限制，比生长速率不断下降，但体积光能吸收速率达到最大并保持恒定，藻细胞进入线性生长期；5 d后光生物反应器“暗区”体积超过了反应器总体积的50%，藻细胞吸收的光能用于维持的比例不断增加，从而导致生长速率下降；培养8 d，转基因聚球藻7942中人源胸腺素a1表达量为4.53 mg/L.     

Cultivation of microalgae for biodiesel production: A review on upstream and downstream processing

Fluctuating market price of fossil fuel and overwhelming emission of greenhouse gases to the atmosphere have resulted in climate change and have been a global concern in this decade.Hence,biodiesel has become an alternative option to fossil diesel as it is renewable and environmentally friendly.Nevertheless,this alternative fuel that is usually derived from terrestrial oil crops will cause shortage in food supply and deforestation if mass production is realized.In recent years,cultivation of aquatic microorganism (particularly microalgae) to produce biodiesel is considered as a practical solution due to their high growth rate and ability to synthesize large quantity of lipid within their cell.However,the development of energy and cost-efficiency of microalgae cultivation system are the main issues in producing renewable microalgae biodiesel.Of late,wastewater or organic compost has been used as the cultivation medium as it can provide sufficient nutrients to sustain microalgae growth.Microalgae cultivation method and system are vitally important as these factors undoubtedly affect the final microalgae biomass and lipid yield.In this review,the cultivation system of microalgae,nutrients demanded for microalgae production,cell harvesting and drying,microalgae oil extraction,and utilization of microalgae biomass for biodiesel production are introduced and discussed.It is anticipated to convey clearer perspectives in upstream and downstream processes in microalgae-derived biodiesel production.     

蓝细菌鱼腥藻7120混合营养培养的生长和生理特征

Mixotrophic growth is one potential mode for mass culture of microalgae and cyanobacteria particularly suitable for the production of high value bioactive compounds and fine chemicals.The typical heterocystous cyanobacterium Anabaena sp.PCC 7120 was grown in the presence of exogenous glucose in light.Glucose improved the cell growth evidently,the maximal specific growth rate under mixotrophic condition(0.38 d1)being 1.6-fold of that of photoautotrophic growth.Mixotrophy caused a variation in cellular pigment composition,increasing the content of chlorophyll a and decreasing the contents of carotenoid and phycobiliprotein relative to chlorophyll a.Fluorescence emission from photosystem II(PSII)relative to photosystem I was enhanced in mixotrophic cells,implying an increased energy distribution in PSII.Glucokinase(EC 2.7.1.2)activity was further induced in the presence of glucose.The mixotrophic culture was scaled up in a 15 L airlift photobioreactor equipped with an inner and an outer light source.A modified Monod model incorporating the specific growth rate and the average light intensity in the reactor was developed to describe cell growth appropriately.The understanding of mixotrophic growth and relevant physiological features of Anabaena sp.PCC 7120 would be meaningful for cultivation and exploitation of this important cyanobacterial strain.