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。     

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。     

微藻规模化培养研究进展

微藻作为地球上最古老的物种之一,其诞生可追溯到35亿多年前.微藻的种类十分丰富,形态也多种多样.微藻一般都含有叶绿体,因此可进行光合作用,有研究表明微藻固定CO2的能力是陆地植物的10倍.微藻以其丰富的代谢产物及独特的生理特性在可再生能源、生物医药、食品工业和环境监测等方面有着广泛的应用.然而如何在控制成本的前提下对微...     

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。     

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。     

产生物柴油微藻培养研究进展

石油的大量使用会导致能源枯竭和温室气体（CO2）排放的增加。为了实现经济和环境的和谐发展,必须使用可再生能源代替石油。可再生能源使用后不会造成温室气体排放的增加。生物柴油是一种理想的可再生能源, 能满足以上要求,所以近年来得到迅速发展。微藻是一种主要利用太阳能固定 CO2,生成制备生物柴油所需油脂的藻类。因此以微藻油脂为原料转化成的生物柴油是石油理想的替代品。简要介绍了产油微藻的种类和微藻油脂的合成,较详细地阐述了微藻自养培养、异养培养、生物反应器、工程微藻的最新研究进展,并初步展望了微藻产油研究的未来发展方向。     

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。     

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。     

能源微藻规模化培养及光生物反应器研究现状与发展策略

引言 众所周知,资源、能源和环境是当前人类社会发展必须面临和解决的三大难题.传统化石能源的过量使用导致了石油资源短缺、全球气候变暖和环境污染.目前,各国政府和企业开始大力开发可再生能源,其中生物能源被认为是最具潜力的可再生能源之一.微藻能源集生物能源、生物固碳及N/P废水处理等多种功能于一体,具有独特的优势,已经成为国内外研究与开发的热点①.能源微藻的低成本规模化培养是实现微藻能源产业化的关键,也是当前限制微藻能源产业化的瓶颈.     

微藻生物柴油的现状与进展

微藻生物柴油能够解决目前使用植物原料发展生物柴油面临的耕地不足、气候变化对产量影响大和引起农作物价格上涨等突出问题。通过转基因技术培育“工程微藻”,繁衍能力高,生长周期短,比陆生植物产油高出几十倍,并且能用海水作为其天然培养基进行工业化生产。介绍了微藻生物柴油的优势,高脂质微藻选育,以及工程微藻研究与下游生产工艺的研究现状和进展。     

Optimizing microalgal production in raceway systems

The industrial exploitation of microalgae is characterized by the production of high‐value compounds. Optimization of the performance of microalgae culture systems is essential to render the process economically viable. For raceway systems, the optimization based on optimal control theory is rather challenging, because the process is by essence periodically forced and, as a consequence, optimization must be carried out in a periodic framework. In this article, we propose a simple operational criterion for raceway systems that when integrated in a strategy of closed‐loop control allows attaining biomass productivities very near to the theoretical maximal productivities. The strategy developed was tested numerically using a mathematical model of microalgae growth in raceways. The model takes into account the temporal variation of the environmental variables temperature and light intensity and their influence on microalgae growth. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29: 543–552, 2013     

Hydrogen production by microalgae

The production of H₂ gas from water and sunlightusing microalgae, `biophotolysis', has been a subjectof applied research since the early 1970s. A numberof approaches have been investigated, but most provedto have fundamental limitations or requireunpredictable research breakthroughs. Examples areprocesses based on nitrogen-fixing microalgae andthose producing H<sub>2</sub> and O<sub>2</sub> simultaneously fromwater (`direct biophotolysis'). The most plausibleprocesses for future applied R & D are those whichcouple separate stages of microalgal photosynthesisand fermentations (`indirect biophotolysis'). Theseinvolve fixation of CO₂ into storagecarbohydrates followed by their conversion to H₂by the reversible hydrogenase, both in dark andpossibly light-driven anaerobic metabolic processes. Based on a preliminary engineering and economicanalysis, biophotolysis processes must achieve closeto an overall 10% solar energy conversion efficiencyto be competitive with alternatives sources ofrenewable H₂, such as photovoltaic-electrolysisprocesses. Such high solar conversion efficiencies inphotosynthetic CO₂ fixation could be reached bygenetically reducing the number of light harvesting(antenna) chlorophylls and other pigments inmicroalgae. Similarly, greatly increased yields ofH₂ from dark fermentation by microalgae could beobtained through application of the techniques ofmetabolic engineering. Another challenge is toscale-up biohydrogen processes with economicallyviable bioreactors.Solar energy driven microalgae processes forbiohydrogen production are potentially large-scale,but also involve long-term and economically high-riskR&D. In the nearer-term, it may be possible tocombine microalgal H₂ production with wastewatertreatment.     

Effect of daytime CO2 supplement on productivity and biochemical composition of Scenedesmus armatus under outdoor cultivation

The cultivation of Scenedesmus armatus was carried out under outdoor Thailand climate conditions. The highest actual growth rate occurred at around 9:00 a.m. to 3:00 p.m., with a wide pH range of 6.4 to 11. The supply of CO₂ had slight influence on growth characteristics but did exert some observable effects on nutritional accumulations. Adding CO₂ from 2 to 15% by volume in the aeration (0.2 vvm) caused an increase in lipid and protein from 19.8 to 25.6 and 37.8 to 48.2% w/w, respectively, whereas carbohydrate decreased from 42.5 to 26.2% w/w. Scenedesmus armatus cultivated with 2% CO₂-enriched air provided the highest the average of the average biomass productivity of 91.25 mg L^?1 d^?1, which corresponded to a CO₂ fixation of 165 mg CO₂ L^?1 d^?1 with the average lipid, protein, and carbohydrate productivities of 22.24, 38.34, and 30.67 mg L^?1 d^?1.     

Botryococcus braunii: A Renewable Source of Hydrocarbons and Other Chemicals

ABSTRACT:?

Botryococcus braunii, a green colonial microalga, is an unusually rich renewable source of hydrocarbons and other chemicals. Hydrocarbons can constitute up to 75% of the dry mass of B. braunii. This review details the various facets of biotechnology of B. braunii, including its microbiology and physiology; production of hydrocarbons and other compounds by the alga; methods of culture; downstream recovery and processing of algal hydrocarbons; and cloning of the algal genes into other microorganisms. B. braunii converts simple inorganic compounds and sunlight to potential hydrocarbon fuels and feedstocks for the chemical industry. Microorganisms such as B. braunii can, in the long run, reduce our dependence on fossil fuels and because of this B. braunii continues to attract much attention.     

Biotechnology of algal biomass production: a review of systems for outdoor mass culture

Microalgae are very efficient solar energy converters and they can produce a great variety of metabolites. Man has always tried to take advantage of these proporties through algal mass culture. Despite the fact that many applications for microalgae have been described in the literature, these micro-organisms are still of minor economic importance. Industrial reactors for algal culture are at present, all designed as open race-ways (shallow open ponds where culture is circulated by a paddle-wheel). Technical and biological limitations of these open systems have given rise to the development of enclosed photoreactors (made of transparent tubes, sleeves or containers and where light source may be natural or artificial). The present review surveys advances in these two technologies for cultivation of microalgae. Starting from published results, the advantages and disadvantages of open systems and closed photobioreactors are discussed. A few open systems are presented for which particularly reliable results are available. Emphasis is then put on closed systems, which have been considered as capital intensive and are justified only when a fine chemical is to be produced.