封闭式光生物反应器研究进展

国际上80～90年代,封闭式光生物反应器是微藻生物技术的重要研究热点,也是微藻生物技术产业化的关键技术之一。本文较全面地介绍了用于微藻大规模培养的封闭式光生物反应器研究现状。将封闭式光生物反应器分为柱式、管式、板式和光导纤维反应器等类型。工业放大前景的管式和板式光生物反应器采取了典型个案分析的方法,列表比较了典型反应器的主要技术参数,并对它们的技术发展趋势进行了归纳总结。     

磁处理光生物反应器的研制及其应用研究

开发出一种新型气升式外环流磁处理光生物反应器,将其应用于钝顶螺旋藻的高细胞密度培养,并从光合作用的角度对磁致生物效应机理进行了初步探讨。光生物反应器主要由反应器主体（气升管道、下降管、除气室）、在线检测与控制系统,以及磁处理、光照、热交换和供所系统组成。结果表明,采用该生物反应器在０＜Ｈ＜３２０ｋＡ／ｍ的磁场强度范围内培养钝顶螺旋藻,不仅能显著加快藻细胞生长速度,而且可提高最大细胞干重浓度。钝顶螺     

用管式光生物反应器培养螺旋藻的研究

微藻大规模培养主要有敞开式大池培养和封闭式光生物反应器培养两种主要方式。管式光生物反应器是封闭式光生物反应器的主要类型之一。与其它类型相比,管式光生物反应器放大较易,成本较低。国外关于管式光生物反应器已有不少研究［１～３］但关于管式光生物反应器产率与光强和光暗比的关系等方面的研究尚未得出明确的结论。国内管式光生物反应器的研究较少［４］,尚未见有关管式光生物反应器中微藻悬浮液流变特性基础参数和产率影响因素的报道。螺旋藻是丝状体蓝藻,螺旋藻蛋白质含量高,其蛋白质所含必需氨基酸丰富,是国内外大规模商业…     

植物细胞培养生物反应器的种类特点及展望

生物反应器技术应用于植物细胞培养既可以打破环境条件的限制,又有助于生产过程的人为调控,为植物细胞大规模培养或工厂化直接生产植物细胞有用代谢产物创造了条件,是当前植物细胞培养工作的研究热点。在介绍植物细胞培养特点的基础上,对适用于植物细胞培养的各类生物反应器(搅拌式生物反应器、非搅拌式生物反应器、用于植物细胞固定化培养的生物反应器、光生物反应器以及一次性培养生物反应器)的原理、优缺点等进行比较分析,最后提出了植物细胞培养生物反应器研究的发展方向,以期为植物细胞培养生物反应器的选择及改良提供参考。     

微藻培养过程的光特性研究进展

微藻培养过程中光的吸收、衰减以及光暗循环等特性是影响微藻的生长速度及其产量的重要因素。本文分析了微藻的光吸收过程、光在微藻培养液中的衰减特性以及微藻培养过程中的光暗循环特性,重点综述了国内外各类光生物反应器中光特性的研究进展,并对其发展方向进行了展望,为微藻培养光生物反应器的设计提供参考依据。     

光生物反应器培养微藻研究进展

微藻具有固定CO2和净化有机废水的能力,在环保、食品饲（饵）料、医药和生物能源开发等领域备受关注,但规模化培养及其产业化仍是研究的难点,亟待解决。就常用于大规模培养微藻的光生物反应器的特点和结构进行了综述。其中,封闭式微藻光生物反应器能够较好地调控藻种的培养条件、不易遭受污染,藻种的纯度容易控制,但培养规模小,生产成本较高;而开放式微藻光生物反应器无法精确控制藻种生长环境,但生产规模大、产量高、生产成本低,因此应用广泛。最佳的方法是综合两者优点,即首先利用封闭式微藻光生物反应器进行中试放大,大量繁殖藻种,然后投入开放式微藻光生物反应器内进行大规模商业生产,此方法有望成为微藻光生物反应器的发展方向,以期为微藻大规模培养提供参考借鉴。     

光生物反应器培养大型海藻细胞或组织

许多大型海藻含有具潜在重要药用价值的次生代谢物质,通常这些物质在藻体中含量极微,大型海藻体本身也不像微藻那样易在短期内大量获取,并且这些物质化学结构复杂,这使得直接提取或者人工合成极为困难。利用光生物反应器培养大型海藻细胞或组织,可以经济、无限量和资源循环再利用的方式,在植物体外合成生产重要的海洋植物次生代谢物质。光生物反应器所提供的可调控和工程优化的培养环境有望成为优化次生代谢物生物合成的有效手段。光生物反应器培养大型海藻细胞或组织也是大型海藻养殖业育苗技术发展的一个重要方向。综述了近10年来光生物反应器培养大型海藻细胞或组织在培养条件以及生长动力学模型方面国内外的研究进展,并对该领域未来可能的研究方向作一展望。     

光照对光生物反应器中微藻高密度光自养培养的影响

光生物反应器是实现微藻高密度培养的重要装置,其设计的关键技术之一是选择合适的光照方式。根据国内外近十年来的相关研究成果,重点介绍了入射光性质(光源、光强、光质和光暗循环)和光能分布对微藻生长的影响,评述了用于微藻高密度培养的光照技术,展望了进一步的研究方向,为高效光生物反应器的设计和优化提供参考。     

微藻养殖中的新型光生物反应器系统

目前世界上微藻的大规模养殖仍普遍采用开放池式生产系统,该系统具有许多不足之处;开发高效、易于控制的新型生产系统是今后开展的趋势。本文对一些新型光生物反应器系统如优化的浅水道工生产系统、密闭管道式、发酵罐式光生物反应器、高密度藻类光生物反应器以及其它类型的光生物反应器进行了较为详细的介绍。     

一种用于微藻培养的新型板式光生物反应器

微藻的闪光效应可以大幅提高微藻的光效率,提高微藻产量。通过在传统的板式光生物反应器中加入斜挡板以增强微藻的闪光效应。以小球藻为模型藻种,考察了新型板式光生物反应器内不同光强和不同进口流速对小球藻生长速率和光效率的影响。结果表明,当进口流速为0.16 m/s时,随着光强的提高,小球藻的细胞浓度逐渐增加,光效率逐渐降低;在500μmol/(m2·s)的光强条件下,小球藻细胞浓度和光效率均随着进口流速的提高而增加。新型板式光生物反应器内小球藻的细胞浓度比传统板式光生物反应器提高了39.23%,表明在传统板式光生物反应器内加入斜挡板可有效增强微藻的闪光效应。     

Use of photoacclimation in the design of a novel photobioreactor to achieve high yields in algal mass cultivation

The concept of a completely new and novel photobioreactor consisting of various compartments each with a specific light regime is described. This is in response to the debate and development which have taken place in recent years concerning photobioreactor design and closed systems. It is well known that algae can photo-acclimate to various light intensities. At the extremes, they can be high light (HL) or low light (LL) acclimated. Both HL and LL acclimated algae typically have very specific characteristics indicating the plasticity of the organisms, which have developed specific strategies during evolution to cope with continuous and dynamic light fields. Not only are these considerations important in photobioreactor design, but also for the production of certain biocompounds, whose synthesis has specific light requirements. In the continuous flow photobioreactor described here, algal cells acclimated to different light conditions together permit utilization of the entire light gradient found in an optically dense medium, such as in a high-density culture. Compared to a single compartment vertical flat-plate photobioreactor, the multicompartment reactor yielded a 37% higher productivity rate. This is a significant improvement in photobioreactor performance.     

Reduction of CO2 by a high-density culture of Chlorella sp. in a semicontinuous photobioreactor

The microalga incorporated photobioreactor is a highly efficient biological system for converting CO2 into biomass. Using microalgal photobioreactor as CO2 mitigation system is a practical approach for elimination of waste gas from the CO2 emission. In this study, the marine microalga Chlorella sp. was cultured in a photobioreactor to assess biomass, lipid productivity and CO2 reduction. We also determined the effects of cell density and CO2 concentration on the growth of Chlorella sp. During an 8-day interval cultures in the semicontinuous cultivation, the specific growth rate and biomass of Chlorella sp. cultures in the conditions aerated 2-15% CO2 were 0.58-0.66 d(-1) and 0.76-0.87 gL(-1), respectively. At CO2 concentrations of 2%, 5%, 10% and 15%, the rate of CO2 reduction was 0.261, 0.316, 0.466 and 0.573 gh(-1), and efficiency of CO2 removal was 58%, 27%, 20% and 16%, respectively. The efficiency of CO2 removal was similar in the single photobioreactor and in the six-parallel photobioreactor. However, CO2 reduction, production of biomass, and production of lipid were six times greater in the six-parallel photobioreactor than those in the single photobioreactor. In conclusion, inhibition of microalgal growth cultured in the system with high CO2 (10-15%) aeration could be overcome via a high-density culture of microalgal inoculum that was adapted to 2% CO2. Moreover, biological reduction of CO2 in the established system could be parallely increased using the photobioreactor consisting of multiple units.     

Improvement of carbon dioxide biofixation in a photobioreactor using Anabaena sp. PCC 7120

The biological photosynthetic process is useful and environmentally benign compared with other carbon dioxide (CO₂) mitigation processes. In the present study, Anabaena sp. PCC 7120 was utilized for carbon dioxide mitigation. A customized airlift photobioreactor was found to provide higher light utilization efficiency and a higher rate of CO₂ biofixation compared with that of a bubble column. The maximum biomass concentrations were 0.71 and 1.13 g L^?1 in the bubble column and airlift photobioreactor, respectively, using BG11₀ medium under aerated conditions. A lower mixing time in the airlift photobioreactor compared with that of the bubble column resulted in improved mass transfer. The CO₂ biofixation rate of Anabaena sp. PCC 7120 was determined using different phosphate concentrations at a light intensity of 120 μE m^?2 s^?1 and 5% (v/v) CO₂-enriched air in the airlift photobioreactor. However, it was observed that the specific growth rate was independent at higher light intensity. In addition, it was observed that increased light intensity, phosphate and CO₂ concentrations could enhance the CO₂ biofixation efficiency to a greater extent.     

A novel photobioreactor with transparent rectangular chambers for cultivation of microalgae

An open tank photobioreactor containing transparent rectangular chambers (TRCs) was developed to improve the photosynthetic efficiency of microalgal cultivation. The TRCs, made of transparent acrylic, conducted light deep into the photobioreactor, especially at high cell concentrations. The average irradiance, I_av, was calculated by Lambert–Beer's law, and was used to determine the light conditions in the cultivation system. The photobioreactor provided large areas of illumination that improved the effective utilization of light energy for microalgae growth and created a good artificial environment for a high rate of cell growth, even at low I_av. The biomass concentration of Chlorella sp. reached 3.745 g L⁻¹ on the 13th day, with biomass productivity of 0.340 g L⁻¹ d⁻¹. The total biomass obtained was 56% more than that of similar culture systems without TRCs.     

微藻培养系统内光现象的研究进展

分析了微藻培养系统内光传递过程的数学模型和光分布影响因素,重点综述了光暗循环对微藻生长影响的实验研究和CFD技术应用研究进展,展望了微藻培养系统内光现象的发展方向,以期为规模化、高效微藻培养光生物反应器的设计、优化和放大提供参考。     

A light distribution model for an internally radiating photobioreactor

Analysis of light energy distribution in culture is important for maximizing the growth efficiency of photosynthetic cells and the productivity of a photobioreactor. To characterize the irradiance conditions in a photobioreactor, we developed a light distribution model for a single-radiator system and then extended the model to multiple radiators using the concept of parallel translation. Mathematical expressions for the local light intensity and the average light intensity were derived for a cylindrical photobioreactor with multiple internal radiators. The proposed model was used to predict the irradiance levels inside an internally radiating photobioreactor using Synechococcus sp. PCC 6301 as a model photosynthetic microorganism. The effects of cell density and radiator number were interpreted through photographic and model simulation studies. The predicted light intensity values were found to be very close to those obtained experimentally, which suggests that the proposed model is capable of accurately interpreting the local light energy profiles inside the photobioreactor system. Due to the simplicity and flexibility of the proposed model, it was also possible to predict the light conditions in other complex photobioreactors, including optical-fiber and pond-type photobioreactors.     

Photobioreactors for microalgal cultures: A Lagrangian model coupling hydrodynamics and kinetics

Closed photobioreactors have to be optimized in terms of light utilization and overall photosynthesis rate. A simple model coupling the hydrodynamics and the photosynthesis kinetics has been proposed to analyze the photosynthesis dynamics due to the continuous shuttle of microalgae between dark and lighted zones of the photobioreactor. Microalgal motion has been described according to a stochastic Lagrangian approach adopting the turbulence model suitable for the photobioreactor configuration (single vs. two‐phase flows). Effects of light path, biomass concentration, turbulence level and irradiance have been reported in terms of overall photosynthesis rate. Different irradiation strategies (internal, lateral and rounding) and several photobioreactor configurations (flat, tubular, bubble column, airlift) have been investigated. Photobioreactor configurations and the operating conditions to maximize the photosynthesis rate have been pointed out. Results confirmed and explained the common experimental observation that high concentrated cultures are not photoinhibited at high irradiance level. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:1259–1272, 2015     

<Emphasis Type="Italic">Chlorella vulgaris</Emphasis> (SAG 211-12) biofilm formation capacity and proposal of a rotating flat plate photobioreactor for more sustainable biomass production

Difficulties and cost of suspended microalgal biomass harvest and processing can be overcome by cultivating microalgae as biofilms. In the present work, a new photoautotrophic biofilm photobioreactor, the rotating flat plate photobioreactor (RFPPB), was developed aiming at a cost-effective production of Chlorella vulgaris (SAG 211-12), a strain not frequently referred in the literature but promising for biofuel production. Protocols were developed for evaluating initial adhesion to different materials and testing the conditions for biofilm formation. Polyvinyl chloride substrate promoted higher adhesion and biofilm production, followed by polypropylene, polyethylene, and stainless steel. The new RFPPB was tested, aiming at optimizing incident light utilization, minimizing footprint area and simplifying biomass harvesting. Tests show that the photobioreactor is robust, promotes biofilm development, and has simple operation, small footprint, and easy biomass harvest. Biomass production (dry weight) under non-optimized conditions was 3.35 g m^?2, and areal productivity was 2.99 g m^?2 day^?1. Lipid content was 10.3% (dw), with high PUFA content. These results are promising and can be improved by optimizing some operational parameters, together with evaluation of long-term photobioreactor maximum productivity.     

Hydrodynamic characteristics and microalgae cultivation in a novel flat‐plate photobioreactor

Flat‐plate photobioreactors (FPPBRs) are widely reported for cultivation of microalgae. In this work, a novel FPPBR mounted with inclined baffles was developed, which can make the fluid produce a “spirality” flow. The flow field and cell trajectory in the photobioreactor were investigated by using computational fluid dynamics. In addition, the cell trajectory was analyzed using a Fast Fourier transformation. The influence of height of the baffles, the angle α between the inclined baffle and fluid inlet flow direction (z), and the fluid inlet velocity on the frequency of flashing light effect and pressure drop were examined to optimize the structure parameters of the inclined baffles and operating conditions of the photobioreactor. The results showed that with inclined baffles built‐in, significant swirl flow could be generated in the FPPBR. In this way, the flashing light effect for microalgal cell could also be achieved and the photosynthesis efficiency of microalgae could be promoted. In outdoor cultivation of freshwater Chlorella sp., the maximum biomass productivity of Chlorella sp. cultivated in the photobioreactor with inclined baffles was 29.94% higher than that of the photobioreactor without inclined baffles. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2013     

The air‐lift photobioreactors with flow patterning for high‐density cultures of microalgae and carbon dioxide removal

A photobioreactor containing microalgae is a highly efficient system for converting carbon dioxide (CO₂) into biomass. Using a microalgal photobioreactor as a CO₂ mitigation system is a practical approach to the problem of CO₂ emission from waste gas. In this study, a marine microalga, Chlorella sp. NCTU‐2, was applied to assess biomass production and CO₂ removal. Three types of photobioreactors were designed and used: (i) without inner column (i.e. a bubble column), (ii) with a centric‐tube column and (iii) with a porous centric‐tube column. The specific growth rates (μ) of the batch cultures in the bubble column, the centric‐tube and the porous centric‐tube photobioreactor were 0.180, 0.226 and 0.252 day^?1, respectively. The porous centric‐tube photobioreactor, operated in semicontinuous culture mode with 10% CO₂ aeration, was evaluated. The results show that the maximum biomass productivity was 0.61 g/L when one fourth of the culture broth was recovered every 2 days. The CO₂ removal efficiency was also determined by measuring the influent and effluent loads at different aeration rates and cell densities of Chlorella sp. NCTU‐2. The results show that the CO₂ removal efficiency was related to biomass concentration and aeration rate. The maximum CO₂ removal efficiency of the Chlorella sp. NCTU‐2 culture was 63% when the biomass was maintained at 5.15 g/L concentration and 0.125 vvm aeration (volume gas per volume broth per min; 10% CO₂ in the aeration gas) in the porous centric‐tube photobioreactor.