Advances in photobioreactors for intensive microalgal production: configurations, operating strategies and applications
01 Feb 2014-Journal of Chemical Technology & Biotechnology (John Wiley & Sons, Ltd)-Vol. 89, Iss: 2, pp 178-195
TL;DR: 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.
Abstract: 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
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TL;DR: This review presents the recent biotechnological developments in microalgal carotenoid production including cultivation, harvesting, extraction, and purification with a specific focus on downstream processing.
441 citations
TL;DR: A techno-economic analysis of microalgae production was conducted, showing that biological productivity, geographical locations and production technology are important factors to lower production cost, and suggesting that focused research efforts can contribute to achieve economically sustainable production of micro algae rich in EPA and DHA for use in aquafeed in the near future.
238 citations
Cites background from "Advances in photobioreactors for in..."
...Major technological advances in design and technical configurations of closed cultivation system have been described over the years to increase productivity, mainly to maximize the utilization of light energy by a high surface-to-volume ratio and short light paths, but also to achieve an efficient mass transfer (uptake of CO2 and nutrients, and removal of O2) through better mixing systems and process control strategies (Olivieri et al., 2014)....
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TL;DR: There is considerable scope for further innovation in harvesting processes, especially with synergistic interactions that exploit multiple physical and chemical properties simultaneously, as well as three pilot-plants across Northwest Europe are detailed.
Abstract: Microalgae are a promising renewable feedstock for a diverse number of products such as fuels, fine chemicals, nutraceuticals, and cosmetics. The extraction and processing of biochemicals from microalgae require the handling of large volumes of feedstock, largely due to the small biomass to liquid ratio, typically This work reviews the developments in microalgae harvesting and details the underlying phenomena of each technology in relation to key physical parameters such as: size, morphology, surface charge, and density. A critical appraisal of each method is given in relation to biomass concentration, biomass recovery, energy consumption and integration into a biorefinery approach. Finally, we detail four microalgae harvesting case studies from pilot-plants across Northwest Europe. The case studies are: (1) membrane filtration of Scenedesmus sp. used for protein, carbohydrate and lipid extraction; (2) synergetic harvesting of cyanobacteria by autoflocculation and passive capillary dewatering for the production of bioactive extracts; and, (3) bioflocculation and filtering of wastewater-grown microalgae for the production of shrimp feed, biogas and fertilizer. Overall, this review highlights that there is considerable scope for further innovation in harvesting processes, especially with synergistic interactions that exploit multiple physical and chemical properties simultaneously.
215 citations
TL;DR: This present review is aimed to gain understanding how microalgae assimilate different forms of carbons and provide a comprehensive overview of the current advances in utilizing microalgai for CO2 fixation, with focus on strain screening and improvement, mass cultivation practice, and effects of environmental and nutritional factors onCO2 fixation performance.
Abstract: Carbon sequestration is an important strategy in combating rising carbon dioxide concentration in the atmosphere. Differing from carbon emission reduction, carbon sequestration offers the possibilities of reducing or avoiding CO2 emission if CO2 is to be captured from large stationary sources and utilization of the captured CO2 for production of chemical and energy. Biological sequestration or bio-mitigation of carbons through microalgal systems, despite in its early stage, represents a promising and sustainable alternative to current carbon mitigation methods. Microalgae consist of a group of highly diverse and fast-growing microorganisms, capable of photoautotrophy, heterotrophy, and mixotrophy. They can be cultivated on non-fertile land with unit CO2 fixation capacity 10–50 times higher than terrestrial plants. Production of food, feed, fine chemicals, and biofuels from microalgal biomass could further enhance the benefits of microalgae-based CO2 fixation. This present review is aimed to gain understanding how microalgae assimilate different forms of carbons and provide a comprehensive overview of the current advances in utilizing microalgae for CO2 fixation, with focus on strain screening and improvement, mass cultivation practice, and effects of environmental and nutritional factors on CO2 fixation performance. Economic viability, challenges and perspectives of microalgae-mediated CO2 bio-mitigation are also discussed.
197 citations
TL;DR: The mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes are summarized and development of combining microalgal biodiesel production with wastewater treatment is especially reviewed.
Abstract: Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgae can be produced under three major cultivation modes, namely photoautotrophic cultivation, heterotrophic cultivation, and mixotrophic cultivation. Potentials and practices of biodiesel production from microalgae have been demonstrated mostly focusing on photoautotrophic cultivation; mixotrophic cultivation of microalgae for biodiesel production has rarely been reviewed. This paper summarizes the mechanisms and virtues of mixotrophic microalgae cultivation through comparison with other major cultivation modes. Influencing factors of microalgal biodiesel production under mixotrophic cultivation are presented, development of combining microalgal biodiesel production with wastewater treatment is especially reviewed, and bottlenecks and strategies for future commercial production are also identified.
186 citations
Cites background from "Advances in photobioreactors for in..."
...photobioreactors was necessary and was extensively researched, among which tubular, flat plate, and column photobioreactors are the most popular forms [27, 29, 115]....
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TL;DR: As demonstrated here, microalgae appear to be the only source of renewable biodiesel that is capable of meeting the global demand for transport fuels.
9,030 citations
TL;DR: The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds).
Abstract: Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO 2 , wastewater treatment, in human health, as food additive, and for aquaculture.
5,158 citations
TL;DR: In this article, the authors reviewed the technologies underpinning microalgae-to-bio-fuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products.
Abstract: Sustainability is a key principle in natural resource management, and it involves operational efficiency, minimisation of environmental impact and socio-economic considerations; all of which are interdependent. It has become increasingly obvious that continued reliance on fossil fuel energy resources is unsustainable, owing to both depleting world reserves and the green house gas emissions associated with their use. Therefore, there are vigorous research initiatives aimed at developing alternative renewable and potentially carbon neutral solid, liquid and gaseous biofuels as alternative energy resources. However, alternate energy resources akin to first generation biofuels derived from terrestrial crops such as sugarcane, sugar beet, maize and rapeseed place an enormous strain on world food markets, contribute to water shortages and precipitate the destruction of the world's forests. Second generation biofuels derived from lignocellulosic agriculture and forest residues and from non-food crop feedstocks address some of the above problems; however there is concern over competing land use or required land use changes. Therefore, based on current knowledge and technology projections, third generation biofuels specifically derived from microalgae are considered to be a technically viable alternative energy resource that is devoid of the major drawbacks associated with first and second generation biofuels. Microalgae are photosynthetic microorganisms with simple growing requirements (light, sugars, CO 2 , N, P, and K) that can produce lipids, proteins and carbohydrates in large amounts over short periods of time. These products can be processed into both biofuels and valuable co-products. This study reviewed the technologies underpinning microalgae-to-biofuels systems, focusing on the biomass production, harvesting, conversion technologies, and the extraction of useful co-products. It also reviewed the synergistic coupling of microalgae propagation with carbon sequestration and wastewater treatment potential for mitigation of environmental impacts associated with energy conversion and utilisation. It was found that, whereas there are outstanding issues related to photosynthetic efficiencies and biomass output, microalgae-derived biofuels could progressively substitute a significant proportion of the fossil fuels required to meet the growing energy demand.
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TL;DR: The first use of microalgae by humans dates back 2000 years to the Chinese, who used Nostoc to survive during famine, while future research should focus on the improvement of production systems and the genetic modification of strains.
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TL;DR: The experiments showed that the eustigmatophyte Nannochloropsis sp.
Abstract: Thirty microalgal strains were screened in the laboratory for their biomass productivity and lipid content. Four strains (two marine and two freshwater), selected because robust, highly productive and with a relatively high lipid content, were cultivated under nitrogen deprivation in 0.6-L bubbled tubes. Only the two marine microalgae accumulated lipid under such conditions. One of them, the eustigmatophyte Nannochloropsis sp. FM102: 100–112. © 2008 Wiley Periodicals, Inc.
2,714 citations