Journal articles on the topic 'Microalgae'
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1
Ramírez, M. E., Y. H. Vélez, L. Rendón, and E. Alzate. "Potential of microalgae in the bioremediation of water with chloride content." Brazilian Journal of Biology 78, no. 3 (October 23, 2017): 472–76. http://dx.doi.org/10.1590/1519-6984.169372.
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Abstract In this work it was carried out the bioremediation of water containing chlorides with native microalgae (MCA) provided by the Centre for study and research in biotechnology (CIBIOT) at Universidad Pontificia Bolivariana. Microalgae presented an adaptation to the water and so the conditions evaluated reaching a production of CO2 in mg L-1 of 53.0, 26.6, 56.0, 16.0 and 30.0 and chloride removal efficiencies of 16.37, 26.03, 40.04, 25.96 and 20.25% for microalgae1, microalgae2, microalgae3, microalgae4 and microalgae5 respectively. Water bioremediation process was carried out with content of chlorides in fed batch system with an initial concentration of chlorides of 20585 mg L-1 every 2 days. The Manipulated variables were: the flow of MCA3 (10% inoculum) for test one; NPK flow for test two, and flow of flow of MCA3+0.5 g L-1 NPK. Chloride removal efficiencies were 66.88%, 63.41% and 66.98% for test one, two and three respectively, for a total bioprocess time of 55 days.
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Postaue, Najla, Leila Cristina Moraes, and Rosa Maria Farias Asmus. "CHORUME COMO FONTE DE NUTRIENTE NA PRODUÇÃO DA BIOMASSA MICROALGAL." e-xacta 12, no. 2 (March 9, 2020): 11. http://dx.doi.org/10.18674/exacta.v12i2.2746.
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A biomassa de microalgas tem apresentado potencial para produção de biodiesel, contudo a viabilidade do cultivo de microalgas depende de fonte de nutrientes de baixo custo. O presente estudo objetivou utilizar o chorume como fonte de nutrientes para microalgas. Os experimentos foram conduzidos visando avaliar a obtenção da biomassa microalgal, conversão de lipídios e rendimento em ésteres metílicos de ácidos graxos, para os meios de cultivos utilizando 5%, 12% e 20% de chorume, com concentrações de 0,02, 0,05 e 0,08 g N. L-1 e para meio de controle contendo 1% de, Nitrogênio (N), Fósforo (P) e Potássio (K), na concentração de 20 g L-1, 5 g L-1 e 20 g L-1, respectivamente. A microalga utilizada neste trabalho foi a de classe Chlorophyceae e família Coccomyxaceae. Os resultados demonstraram que o meio com concentração de 12% de chorume obteve melhores resultados, possibilitando alcançar 1,19 g de biomassa, conversão de 108,15 mg g-1 de lipídios e conteúdo de ésteres de 410,77mg g-1, a microalga utilizada apresentou ainda predominância dos ácidos graxos palmítico e oleico, apresentando baixa quantidade de ácidos graxos saturados o que pode fornecer ao combustível, resistência ao frio. E tais aspectos demonstraram que o chorume pode ser uma fonte promissora de nutrientes para o cultivo das microalgas estudadas. AbstractMicroalgae biomass has presented potential for biodiesel production, however the viability of microalgae cultivation depends on low cost nutrient source. The present study aimed to use leachate as a source of nutrients for microalgae. The experiments were conducted to evaluate the microalgal biomass, lipid conversion and yield in fatty acid methyl esters, for the culture media using 5%, 12% and 20% leachate, with concentrations of 0.02, 0.05 and 0.08 g N. L-1 and for control medium containing 1% Nitrogen (N), Phosphorus (P) and Potassium (K), at a concentration of 20 g L-1, 5 g L-1 and 20 g L-1, respectively. The microalgae used in this work was Chlorophyceae class and Coccomyxaceae family. The results showed that the medium with a concentration of 12% of leachate obtained better results, allowing to reach 1.19 g of biomass, conversion of 108.15 mg g-1 of lipids and esters content of 410,77 mg g-1. The microalgae used also presented predominance of palmitic and oleic fatty acids, presenting low amount of saturated fatty acids which can provide the fuel with cold resistance. And these aspects demonstrated that the leachate can be a promising source of nutrients for the cultivation of the studied microalgae.
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Gonzalez, Luz E., and Yoav Bashan. "Increased Growth of the Microalga Chlorella vulgariswhen Coimmobilized and Cocultured in Alginate Beads with the Plant-Growth-Promoting Bacterium Azospirillum brasilense." Applied and Environmental Microbiology 66, no. 4 (April 1, 2000): 1527–31. http://dx.doi.org/10.1128/aem.66.4.1527-1531.2000.
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ABSTRACT Coimmobilization of the freshwater microalga Chlorella vulgaris and the plant-growth-promoting bacteriumAzospirillum brasilense in small alginate beads resulted in a significantly increased growth of the microalga. Dry and fresh weight, total number of cells, size of the microalgal clusters (colonies) within the bead, number of microalgal cells per cluster, and the levels of microalgal pigments significantly increased. Light microscopy revealed that both microorganisms colonized the same cavities inside the beads, though the microalgae tended to concentrate in the more aerated periphery while the bacteria colonized the entire bead. The effect of indole-3-acetic acid addition to microalgal culture prior to immobilization of microorganisms in alginate beads partially imitated the effect of A. brasilense. We propose that coimmobilization of microalgae and plant-growth-promoting bacteria is an effective means of increasing microalgal populations within confined environments.
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Barbara Araújo, Wesley Machado, Luiz Rodrigo Ito Morioka, Mayara Mari Murata, Josemeyre Bonifácio Da Silva, and Helio Hiroshi Suguimoto. "Uso de Microalgas como Bioestimuladoras da Germinação de Sementes." UNICIÊNCIAS 26, no. 1 (June 23, 2022): 58–62. http://dx.doi.org/10.17921/1415-5141.2022v26n1p58-62.
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As microalgas possuem diversas aplicações biotecnológicas e dentro da agricultura podem ser utilizadas como biofertilizantes, bioestimuladoras da germinação de semente, biopesticidas e bioinsetisidas. Para estudar experimentalmente o uso da microalga Chlorella sorokiniana na germinação de sementes, é necessário obter informações na literatura sobre as metodologias de aplicação de microalgas em experimentos de campo que visem este processo. O presente trabalho teve como objetivo coletar informações por meio de uma revisão de literatura, sobre as metodologias e formas de aplicação das microalgas na germinação de sementes. O trabalho de revisão foi realizado na base de dados do Google Acadêmico com os seguintes termos de busca avançada: *seeds germination and biostimulant agent and Chlorella microalgae* -wastewater, nos anos de 2018 a 2022. Foram encontrados 164 artigos científicos dentro da temática estudada e foram selecionados somente aqueles trabalhos que apresentavam em suas metodologias as informações sobre a aplicação de microalgas em experimentos de campo e germinação de sementes, totalizando 5 artigos. As microalgas comprovadamente apresentam efeitos positivos na germinação de sementes de feijão, agrião, beterraba, tomate e pepino. Contudo é evidente a necessidade de se investir em pesquisas que considerem as diferentes variáveis nesta ação bioestimuladora, como espécies de microalgas, tipo de extratos (cultura inteira, sobrenadante, biomassa seca ou úmida), extração dos compostos bioativos da microalga, além de quantidade e método de aplicação. Palavras-chave: Chlorella sorokiniana. Agricultura Sustentável. Compostos Bioativos. Métodos de Extração. Abstract Microalgae have several biotechnological applications and in agriculture it can be used as biofertilizers, seed germination biostimulators, biopesticides and bioinsecticides. In order to study the use of microalgae Chlorella sorokiniana in seed germination, it is necessary to obtain information in the literature regarding methodologies for applying microalgae in field experiments. The present work aimed to collect information through a literature review, on methodologies and forms of microalgae application in seed germination. The review was carried out at Google Scholar database using the keywords: *seeds germination and biostimulant agent and Chlorella microalgae* -wastewater, from 2018 to 2022. 164 scientific articles were found but only studies that presented information about microalgae application in field experiments and seed germination were selected, totalizing 5 articles. Microalgae showed positive effects on germination of beans, watercress, beetroot, tomato and cucumber seeds. However, it is evident the need to invest in research that considers different variables in biostimulating action, such as microalgae species, type of extracts (whole culture, supernatant, dry or wet biomass), extraction of bioactive compounds, in addition to quantity and application method. Keywords: Chlorella sorokiniana. Sustainable Agriculture. Bioactive Compounds. Extraction Methods.
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Fernandes, Tomásia, and Nereida Cordeiro. "Microalgae as Sustainable Biofactories to Produce High-Value Lipids: Biodiversity, Exploitation, and Biotechnological Applications." Marine Drugs 19, no. 10 (October 14, 2021): 573. http://dx.doi.org/10.3390/md19100573.
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Microalgae are often called “sustainable biofactories” due to their dual potential to mitigate atmospheric carbon dioxide and produce a great diversity of high-value compounds. Nevertheless, the successful exploitation of microalgae as biofactories for industrial scale is dependent on choosing the right microalga and optimum growth conditions. Due to the rich biodiversity of microalgae, a screening pipeline should be developed to perform microalgal strain selection exploring their growth, robustness, and metabolite production. Current prospects in microalgal biotechnology are turning their focus to high-value lipids for pharmaceutic, nutraceutic, and cosmetic products. Within microalgal lipid fraction, polyunsaturated fatty acids and carotenoids are broadly recognized for their vital functions in human organisms. Microalgal-derived phytosterols are still an underexploited lipid resource despite presenting promising biological activities, including neuroprotective, anti-inflammatory, anti-cancer, neuromodulatory, immunomodulatory, and apoptosis inductive effects. To modulate microalgal biochemical composition, according to the intended field of application, it is important to know the contribution of each cultivation factor, or their combined effects, for the wanted product accumulation. Microalgae have a vital role to play in future low-carbon economy. Since microalgal biodiesel is still costly, it is desirable to explore the potential of oleaginous species for its high-value lipids which present great global market prospects.
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Gonzalez-Bashan, Luz E., Vladimir K. Lebsky, Juan P. Hernandez, Jose J. Bustillos, and Yoav Bashan. "Changes in the metabolism of the microalga Chlorella vulgaris when coimmobilized in alginate with the nitrogen-fixing Phyllobacterium myrsinacearum." Canadian Journal of Microbiology 46, no. 7 (July 1, 2000): 653–59. http://dx.doi.org/10.1139/w00-041.
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In an agroindustrial wastewater pond, a naturally occurring unicellular microalga, Chlorella vulgaris, was closely associated with the terrestrial plant-associative N2-fixing bacterium Phyllobacterium myrsinacearum. When the two microorganisms were artificially coimmobilized in alginate beads, they shared the same internal bead cavities, and the production of five microalgal pigments increased, but there were no effects on the number of the cells or the biomass of the microalga. The association, however, reduces the ability of C. vulgaris to remove ammonium ions and phosphorus from water. The bacterium produced nitrate from ammonium in synthetic wastewater with or without the presence of the microalga, and fixed nitrogen in two culture media. Our results suggest that interactions between microalgae and associative bacteria should be considered when cultivating microalgae for wastewater treatment.Key words: alginate, bacterial immobilization, microalgae, nitrogen fixation, Phyllobacterium, wastewater treatment.
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Ajala, E. O., M. A. Ajala, G. S. Akinpelu, and V. C. Akubude. "Cultivation and Processing of Microalgae for Its Sustainability as a Feedstock for Biodiesel Production." Nigerian Journal of Technological Development 18, no. 4 (February 9, 2022): 322–43. http://dx.doi.org/10.4314/njtd.v18i4.8.
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Microalgae are becoming sustainable alternative feedstocks to food crops for biodiesel production which can also solve the problems associated with the use of fossil fuels. However, several challenges about microalgae’s cultivation, harvesting, pre-treatment and extraction processes as well as the technology of biodiesel production affect its sustainability. This study proffers solutions to these challenges and recommended that hybrid culture systems with genetically engineered microalgal species would overcome the challenges of cultivation. The coagulation/flocculation method was adjudged the best harvesting process of the microalgae for its sustainability for biodiesel production. The pre-treatment by ultrasound coupled with enzymatic extraction was suggested best, due to their numerous advantages over other methods. A novel integrated ultrasound-enzyme-enzyme in-situ pre-treatment-extraction-transesterification design is considered a sustainable approach to utilising microalgae biomass for biodiesel production. The study concludes that the microalgae biomass is more than sufficient to meet the global energy demand and can be economically harnessed as a sustainable feedstock for biodiesel production.
HIGHLIGHTS
•Microalgae contain sufficient characteristics for their sustainability for biodiesel production.• Implementation of genetic strategies of microalgal species by cultivating in a hybrid system is the key to microalgae sustainability.• Harvesting of microalgae by coagulation/flocculation method would promote its efficient lipid recovery.• Microalgae are novel feedstocks with a rigid cell wall, its lipid extraction requires the use of effective and efficient pre-treatment.• The ultrasound-enzymatic extraction and enzymatic transesterification in an in-situ process can sustainably utilise microalgae biomass for biodiesel production.
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Journal, Baghdad Science. "Microalgae Chlorella Vulgaris Harvesting Via Co-Pelletization with Filamentous Fungus." Baghdad Science Journal 15, no. 1 (March 4, 2018): 31–36. http://dx.doi.org/10.21123/bsj.15.1.31-36.
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The objective of this study was to progress another method for coagulation/flocculation of the microalga Chlorella vulgaris via pellet-forming of the fungal species Aspergillus niger which was isolated from municipal wastewater mud and the facultative heterotrophic microalga "C.vulgaris was used. The main factors studies were spore inoculums, organic carbon concentration in medium as well as pH variation which had considerably positive effects on microalgae/fungi co-pelletization formation. The process parameters are an inoculum1×104 spores/ML, 15 g/l sucrose as carbon source and pH ranged from 5 - 7.0 were found optimal for efficient microalgae/fungi co-pelletization formation. For autotrophic growth, when pH of culture broth was adjusted to 5.0 -7.0 with organic carbon addition (15 g/L sucrose), almost complete harvesting efficiency of the microalga was achieved. Furthermore, it was observed that diameter and the concentration of microalgae/fungi pellets were pretentious by the shaker rotation. The new harvesting technology established in this study will decrease the microalga harvesting cost and will be possible to adapt this technique to all microalgal species as an alternative to other old-style harvesting approaches.
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Wang, Hui, Haywood D. Laughinghouse, Matthew A. Anderson, Feng Chen, Ernest Willliams, Allen R. Place, Odi Zmora, Yonathan Zohar, Tianling Zheng, and Russell T. Hill. "Novel Bacterial Isolate from Permian Groundwater, Capable of Aggregating Potential Biofuel-Producing Microalga Nannochloropsis oceanica IMET1." Applied and Environmental Microbiology 78, no. 5 (December 22, 2011): 1445–53. http://dx.doi.org/10.1128/aem.06474-11.
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ABSTRACTIncreasing petroleum costs and climate change have resulted in microalgae receiving attention as potential biofuel producers. Little information is available on the diversity and functions of bacterial communities associated with biofuel-producing algae. A potential biofuel-producing microalgal strain,Nannochloropsis oceanicaIMET1, was grown in Permian groundwater. Changes in the bacterial community structure at three temperatures were monitored by two culture-independent methods, and culturable bacteria were characterized. After 9 days of incubation,N. oceanicaIMET1 began to aggregate and precipitate in cultures grown at 30°C, whereas cells remained uniformly distributed at 15°C and 25°C. The bacterial communities in cultures at 30°C changed markedly. Some bacteria isolated only at 30°C were tested for their potential for aggregating microalgae. A novel bacterium designated HW001 showed a remarkable ability to aggregateN. oceanicaIMET1, causing microalgal cells to aggregate after 3 days of incubation, while the total lipid content of the microalgal cells was not affected. Direct interaction of HW001 andN. oceanicais necessary for aggregation. HW001 can also aggregate the microalgaeN. oceanicaCT-1,Tetraselmis suecica, andT. chuiias well as the cyanobacteriumSynechococcusWH8007. 16S rRNA gene sequence comparisons indicated the great novelty of this strain, which exhibited only 89% sequence similarity with any previously cultured bacteria. Specific primers targeted to HW001 revealed that the strain originated from the Permian groundwater. This study of the bacterial communities associated with potential biofuel-producing microalgae addresses a little-investigated area of microalgal biofuel research and provides a novel approach to harvest biofuel-producing microalgae by using the novel bacterium strain HW001.
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Baldisserotto, Costanza, Sara Demaria, Ornella Accoto, Roberta Marchesini, Marcello Zanella, Linda Benetti, Francesco Avolio, Michele Maglie, Lorenzo Ferroni, and Simonetta Pancaldi. "Removal of Nitrogen and Phosphorus from Thickening Effluent of an Urban Wastewater Treatment Plant by an Isolated Green Microalga." Plants 9, no. 12 (December 18, 2020): 1802. http://dx.doi.org/10.3390/plants9121802.
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Microalgae are photosynthetic microorganisms and are considered excellent candidates for a wide range of biotechnological applications, including the removal of nutrients from urban wastewaters, which they can recover and convert into biomass. Microalgae-based systems can be integrated into conventional urban wastewater treatment plants (WW-TP) to improve the water depuration process. However, microalgal strain selection represents a crucial step for effective phytoremediation. In this work, a microalga isolated from the effluent derived from the thickening stage of waste sludge of an urban WW-TP was selected and tested to highlight its potential for nutrient removal. Ammonium and phosphate abatements by microalgae were evaluated using both the effluent and a synthetic medium in a comparative approach. Parallelly, the isolate was characterized in terms of growth capability, morphology, photosynthetic pigment content and photosystem II maximum quantum yield. The isolated microalga showed surprisingly high biomass yield and removal efficiency of both ammonium and phosphate ions from the effluent but not from the synthetic medium. This suggests its clear preference to grow in the effluent, linked to the overall characteristics of this matrix. Moreover, biomass from microalgae cultivated in wastewater was enriched in photosynthetic pigments, polyphosphates, proteins and starch, but not lipids, suggesting its possible use as a biofertilizer.
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Pérez -Morales, A., A. Martínez -López, and J. M. Camalich -Carpizo. "DRY WEIGHT, CARBON, C/N RATIO, HYDROGEN, AND CHLOROPHYLL VARIATION DURING EXPONENTIAL GROWTH OF SELECTED MICROALGAE SPECIES USED IN AQUACULTURE." CICIMAR Oceánides 30, no. 1 (June 27, 2015): 33. http://dx.doi.org/10.37543/oceanides.v30i1.168.
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Microalgae are commonly used as food source in aquaculture, mainly for shellfish and larvae of crustacean and fish. All hatcheries need an excellent inoculum to produce high-quality microalgae when cultured outdoor in extensive systems, and this depends largely on the health of the microalgae cultured under laboratory conditions as a primary step. Therefore, the aim of this work was to assess variations of dry weight, carbon, C/N ratio, hydrogen and chlorophylls as physiological indicators of nutrients uptake and growth rate during exponential growth of Isochrysis galbana, Chaetoceros calcitrans and Dunaliella tertiolecta, using f/2 as culture medium. Chaetoceros calcitrans and D. tertiolecta had higher carbon content (~30 pg cell-1). The C/N ratio varied widely, gradually decreasing on I. galbana. Chlorophyll a varied among the three microalgae tested, ranging from 0.25 pg cell-1. Growth rate was higher in I. galbana (K’ 0.83) followed by D. tertiolecta and C. calcitrans. Results showed that nutrient incorporation by cell change when cell density increases; this information provides new insights in the physiology of marine microalgae and confirms that nutrient uptake dynamics is different in each microalga species. Finally, this study indicates that using one culture medium is not equally efficient for all microalgae used in aquaculture since each species has specific nutritional requirements. Variación de peso seco, carbono, relación C/N, hidrógeno y clorofilas durante el crecimiento exponencial de especies selectas de microalgas utilizadas en acuacultura Las microalgas son comúnmente utilizadas como fuente de alimento en acuacultura, principalmente para cultivo de moluscos y para las fases larvarias de crustáceos y peces. Los criaderos de larvas necesitan un excelente inóculo para producir microalgas de alta calidad cuando se cultivan al exterior en sistemas extensivos; esto depende principalmente de la salud de las microalgas cultivadas bajo condiciones de laboratorio como primer paso. Por lo tanto, el objetivo de este trabajo fue evaluar variaciones de peso seco, carbono, relación C/N, hidrógeno y clorofilas como indicadores fisiológicos de la asimilación de nutrientes y tasa de crecimiento durante el crecimiento exponencial de Isochrysis galbana, Chaetoceros calcitrans y Dunaliella tertiolecta, usando f/2 como medio de cultivo. Chaetoceros calcitrans y D. tertiolecta presentaron el mayor contenido de carbono (~30 pg cél-1). La relación C/N varió ampliamente, decreciendo gradualmente en I. galbana. La clorofila a fue la que más varió entre las tres microalgas evaluadas, en el intervalo de 0.25 pg cél-1. La tasa de crecimiento fue mayor en I. galbana (K’ 0.83) seguido por D. tertiolecta y C. calcitrans. Los resultados mostraron que la incorporación de nutrientes por célula cambia cuando la densidad celular se incrementa; esta información provee nuevo conocimiento sobre la fisiología de microalgas marinas y confirma que la dinámica de incorporación de nutrientes es diferente en cada especie de microalga. Por último, este estudio indicó que el uso de un solo medio de cultivo no es igualmente eficiente para todas las microalgas usadas en acuacultura, debido a que necesitan requerimientos nutricionales específicos.
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Pérez -Morales, A., A. Martínez -López, and J. M. Camalich -Carpizo. "DRY WEIGHT, CARBON, C/N RATIO, HYDROGEN, AND CHLOROPHYLL VARIATION DURING EXPONENTIAL GROWTH OF SELECTED MICROALGAE SPECIES USED IN AQUACULTURE." CICIMAR Oceánides 30, no. 1 (June 27, 2015): 33. http://dx.doi.org/10.37543/oceanides.v30i1.168.
Full textAbstract:
Microalgae are commonly used as food source in aquaculture, mainly for shellfish and larvae of crustacean and fish. All hatcheries need an excellent inoculum to produce high-quality microalgae when cultured outdoor in extensive systems, and this depends largely on the health of the microalgae cultured under laboratory conditions as a primary step. Therefore, the aim of this work was to assess variations of dry weight, carbon, C/N ratio, hydrogen and chlorophylls as physiological indicators of nutrients uptake and growth rate during exponential growth of Isochrysis galbana, Chaetoceros calcitrans and Dunaliella tertiolecta, using f/2 as culture medium. Chaetoceros calcitrans and D. tertiolecta had higher carbon content (~30 pg cell-1). The C/N ratio varied widely, gradually decreasing on I. galbana. Chlorophyll a varied among the three microalgae tested, ranging from 0.25 pg cell-1. Growth rate was higher in I. galbana (K’ 0.83) followed by D. tertiolecta and C. calcitrans. Results showed that nutrient incorporation by cell change when cell density increases; this information provides new insights in the physiology of marine microalgae and confirms that nutrient uptake dynamics is different in each microalga species. Finally, this study indicates that using one culture medium is not equally efficient for all microalgae used in aquaculture since each species has specific nutritional requirements. Variación de peso seco, carbono, relación C/N, hidrógeno y clorofilas durante el crecimiento exponencial de especies selectas de microalgas utilizadas en acuacultura Las microalgas son comúnmente utilizadas como fuente de alimento en acuacultura, principalmente para cultivo de moluscos y para las fases larvarias de crustáceos y peces. Los criaderos de larvas necesitan un excelente inóculo para producir microalgas de alta calidad cuando se cultivan al exterior en sistemas extensivos; esto depende principalmente de la salud de las microalgas cultivadas bajo condiciones de laboratorio como primer paso. Por lo tanto, el objetivo de este trabajo fue evaluar variaciones de peso seco, carbono, relación C/N, hidrógeno y clorofilas como indicadores fisiológicos de la asimilación de nutrientes y tasa de crecimiento durante el crecimiento exponencial de Isochrysis galbana, Chaetoceros calcitrans y Dunaliella tertiolecta, usando f/2 como medio de cultivo. Chaetoceros calcitrans y D. tertiolecta presentaron el mayor contenido de carbono (~30 pg cél-1). La relación C/N varió ampliamente, decreciendo gradualmente en I. galbana. La clorofila a fue la que más varió entre las tres microalgas evaluadas, en el intervalo de 0.25 pg cél-1. La tasa de crecimiento fue mayor en I. galbana (K’ 0.83) seguido por D. tertiolecta y C. calcitrans. Los resultados mostraron que la incorporación de nutrientes por célula cambia cuando la densidad celular se incrementa; esta información provee nuevo conocimiento sobre la fisiología de microalgas marinas y confirma que la dinámica de incorporación de nutrientes es diferente en cada especie de microalga. Por último, este estudio indicó que el uso de un solo medio de cultivo no es igualmente eficiente para todas las microalgas usadas en acuacultura, debido a que necesitan requerimientos nutricionales específicos.
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Pathom-aree, Wasu, Sritip Sensupa, Antira Wichaphian, Nanthakrit Sriket, Benyapa Kitwetch, Jeeraporn Pekkoh, Pachara Sattayawat, Sureeporn Lomakool, Yupa Chromkaew, and Sirasit Srinuanpan. "An Innovative Co-Cultivation of Microalgae and Actinomycete-Inoculated Lettuce in a Hydroponic Deep-Water Culture System for the Sustainable Development of a Food–Agriculture–Energy Nexus." Horticulturae 10, no. 1 (January 10, 2024): 70. http://dx.doi.org/10.3390/horticulturae10010070.
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In recent years, researchers have turned their attention to the co-cultivation of microalgae and plants as a means to enhance the growth of hydroponically cultivated plants while concurrently producing microalgal biomass. However, the techniques used require precise calibration based on plant growth responses and their interactions with the environment and cultivation conditions. This study initially focused on examining the impact of hydroponic nutrient concentrations on the growth of the microalga Chlorella sp. AARL G049. The findings revealed that hydroponic nutrient solutions with electrical conductivities (EC) of 450 µS/cm and 900 µS/cm elicited a positive response in microalgae growth, resulting in high-quality biomass characterized by an elevated lipid content and favorable properties for renewable biodiesel. The biomass also exhibited high levels of polyunsaturated fatty acids (PUFAs), indicating excellent nutritional indices. The microalgae culture and microalgae-free culture, along with inoculation-free lettuce (Lactuca sativa L. var. longifolia) and lettuce that was inoculated with plant growth actinobacteria, specifically the actinomycete Streptomyces thermocarboxydus S3, were subsequently integrated into a hydroponic deep-water culture system. The results indicated that several growth parameters of lettuce cultivated in treatments incorporating microalgae experienced a reduction of approximately 50% compared to treatments without microalgae, and lowering EC levels in the nutrient solution from 900 µS/cm to 450 µS/cm resulted in a similar approximately 50% reduction in lettuce growth. Nevertheless, the adverse impacts of microalgae and nutrient stress were alleviated through the inoculation with actinomycetes. Even though the co-cultivation system leads to reduced lettuce growth, the system enables the production of high-value microalgal biomass with exceptional biodiesel fuel properties, including superior oxidative stability (>13 h), a commendable cetane number (>62), and a high heating value (>40 MJ/kg). This biomass, with its potential as a renewable biodiesel feedstock, has the capacity to augment the overall profitability of the process. Hence, the co-cultivation of microalgae and actinomycete-inoculated lettuce appears to be a viable approach not only for hydroponic lettuce cultivation but also for the generation of microalgal biomass with potential applications in renewable energy.
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Van Anh, Le Thi, Tran Ngoc Anh Thu, and Nguyen Thi Dong Phuong. "Investigation of microalgae culture by autoflocculation methodologies." Vietnam Journal of Biotechnology 20, no. 3 (September 30, 2022): 487–94. http://dx.doi.org/10.15625/1811-4989/17059.
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Harvesting of microalgae from their different cultivation media has pointed out challenges in resolving the problems of flocculation. These challenges must be faced with a suitable method for inducing flocculation that avoid or limit the microalgae’s contamination. This study developed the fundamental experiments with a support of chemicals and some bacteria strains inducing the flocculation of Chlorella vulgaris SAG 211-19. Particularly, the determination of minimum content of Mg2+, Ca2+, E. coli ATCC 85922 and Bacillus subtilis MT300405 was effectuated with co-cultivation of microalgae and set up in batch culture in Bold’s Basal Medium. As a result, the adjustment in 25 minutes of 199.2 mg/L CaCl2.2H2O, 50 mg/L KH2PO4, and of 141 mg/L MgSO4.7H2O induced a microalgal settling efficiency of 81% and 70%, respectively. Meanwhile, the perfomance of microalgal removing reached up to 83.6% and 84% by the inoculation into microalgal culture media of a minimum initial cell density of 8.1 ´ 105 CFU/mL of Bacillus subtilis MT300405 and 12 ´ 105 CFU/mL of E. coli ATCC 85922, respectively. The flocculation of microalgal cells by bacterial inoculation did not require a high pH adjustment as in the case of salt addition.
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Kuo, Chiu-Mei, Yu-Ling Sun, Cheng-Han Lin, Chao-Hsu Lin, Hsi-Tien Wu, and Chih-Sheng Lin. "Cultivation and Biorefinery of Microalgae (Chlorella sp.) for Producing Biofuels and Other Byproducts: A Review." Sustainability 13, no. 23 (December 6, 2021): 13480. http://dx.doi.org/10.3390/su132313480.
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Microalgae-based carbon dioxide (CO2) biofixation and biorefinery are the most efficient methods of biological CO2 reduction and reutilization. The diversification and high-value byproducts of microalgal biomass, known as microalgae-based biorefinery, are considered the most promising platforms for the sustainable development of energy and the environment, in addition to the improvement and integration of microalgal cultivation, scale-up, harvest, and extraction technologies. In this review, the factors influencing CO2 biofixation by microalgae, including microalgal strains, flue gas, wastewater, light, pH, temperature, and microalgae cultivation systems are summarized. Moreover, the biorefinery of Chlorella biomass for producing biofuels and its byproducts, such as fine chemicals, feed additives, and high-value products, are also discussed. The technical and economic assessments (TEAs) and life cycle assessments (LCAs) are introduced to evaluate the sustainability of microalgae CO2 fixation technology. This review provides detailed insights on the adjusted factors of microalgal cultivation to establish sustainable biological CO2 fixation technology, and the diversified applications of microalgal biomass in biorefinery. The economic and environmental sustainability, and the limitations and needs of microalgal CO2 fixation, are discussed. Finally, future research directions are provided for CO2 reduction by microalgae.
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Glazunova, D. M., P. Yu Galitskaya, and S. Yu Selivanovskaya. "Atmospheric Carbon Sequestration Using Microalgae." Uchenye Zapiski Kazanskogo Universiteta Seriya Estestvennye Nauki 166, no. 1 (March 15, 2024): 82–125. http://dx.doi.org/10.26907/2542-064x.2024.1.82-125.
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This article outlines biotechnological methods that can help reduce atmospheric and industrial carbon dioxide emissions through the use of microalgae. A general description of microalgae was provided, and the most promising species for microalgal biotechnology were identified. The metabolic process by which microalgae capture and degrade carbon dioxide was described. The microalgae-based biotechnological systems and devices available today were analyzed. The key factors that need to be considered for the effective and successful use of microalgae were highlighted. Different products obtained from microalgal biomass after atmospheric carbon dioxide sequestration were overviewed.
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Takahashi, Toshiyuki. "Potential of an Automated- and Image-Based Cell Counter to Accelerate Microalgal Research and Applications." Energies 13, no. 22 (November 18, 2020): 6019. http://dx.doi.org/10.3390/en13226019.
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Efforts to achieve Sustainable Development Goals (SDGs) have resulted in enhancement of the position of microalgae in feedstocks for food, feed, healthcare, and biofuels. However, stabile microalgal biorefineries require a sustainable and reliable management system of microalgae, which are sensitive to environmental changes. To expand microalgal applicability, assessment and maintenance of microalgal quality are crucial. Compared with conventional methods, including hemocytometry and turbidity, an automated- and image-based cell counter contributes to the establishment of routine management of microalgae with reduced work burden. This review presents the principle of an automated cell counter and highlights the functional capacities of the device for microalgal management. The method utilizing fluorescence function to evaluate the chlorophyll integrity of microalgae may lay the groundwork for making a large variety of microalgal biorefineries, creating an important step toward achieving SDGs.
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Silva, Samara C., Isabel C. F. R. Ferreira, Madalena M. Dias, and M. Filomena Barreiro. "Microalgae-Derived Pigments: A 10-Year Bibliometric Review and Industry and Market Trend Analysis." Molecules 25, no. 15 (July 28, 2020): 3406. http://dx.doi.org/10.3390/molecules25153406.
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Microalgae productive chains are gaining importance as sustainable alternatives to obtain natural pigments. This work presents a review on the most promising pigments and microalgal sources by gathering trends from a 10-year bibliometric survey, a patents search, and an industrial and market analysis built from available market reports, projects and companies’ webpages. The performed analysis pointed out chlorophylls, phycocyanin, astaxanthin, and β-carotene as the most relevant pigments, and Chlorella vulgaris, Spirulina platensis, Haematococcus pluvialis, and Dunaliella salina, respectively, as the most studied sources. Haematococcus is referred in the highest number of patents, corroborating a high technological interest in this microalga. The biorefinery concept, investment in projects and companies related to microalgae cultivation and/or pigment extraction is increasingly growing, particularly, for phycocyanin from Spirulina platensis. These pieces of evidence are a step forward to consolidate the microalgal pigments market, which is expected to grow in the coming years, increasing the prospects of replacing synthetic pigments by natural counterparts.
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Bansfield, Danielle, Kristian Spilling, Anna Mikola, and Jonna Piiparinen. "Bioflocculation of Euglena gracilis via direct application of fungal filaments: a rapid harvesting method." Journal of Applied Phycology 34, no. 1 (November 30, 2021): 321–34. http://dx.doi.org/10.1007/s10811-021-02651-5.
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AbstractThe high cost and environmental impact of traditional microalgal harvesting methods limit commercialization of microalgal biomass. Fungal bioflocculation of microalgae is a promising low-cost, eco-friendly method but the range of fungal and microalgal species tested to date is narrow. Here, eight non-pathogenic, filamentous fungi were screened for their ability to self-pelletize and flocculate Euglena gracilis (ca.50 µm motile microalga) in suspension. Self-pelletization was tested under various rotational speeds, and species which formed pellets (Ø > 0.5 cm) were selected for harvesting tests. Filaments of each species were combined with E. gracilis at various ratios based on dry weight. Harvesting efficiency was determined by measuring the change in cell counts over time, and settling of the flocs was evaluated by batch settling tests. Three fungal species, Ganoderma lucidum, Pleurotus ostreatus, and Penicillium restrictum, were able to reliably flocculate and harvest 62–75% of the microalgae while leaving it unharmed. The results demonstrated that self-pelletization, harvesting, and settling were dependent on the fungal species. The fungi to algae ratio also had significant but contrasting effects on harvesting and settling. In balancing the needs to both harvest and settle the biomass, the optimal fungi to algae ratio was 1:2. The application of fungal filaments to microalgae in suspension produced readily settling flocs and was less time-consuming than other commonly used methods. This method is especially attractive for harvesting microalgal biomass for low-value products where speed, low cost, and cell integrity is vital.
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Al-Jabri, Hareb, Probir Das, Shoyeb Khan, Mahmoud Thaher, and Mohammed AbdulQuadir. "Treatment of Wastewaters by Microalgae and the Potential Applications of the Produced Biomass—A Review." Water 13, no. 1 (December 25, 2020): 27. http://dx.doi.org/10.3390/w13010027.
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The treatment of different types of wastewater by physicochemical or biological (non-microalgal) methods could often be either inefficient or energy-intensive. Microalgae are ubiquitous microscopic organisms, which thrive in water bodies that contain the necessary nutrients. Wastewaters are typically contaminated with nitrogen, phosphorus, and other trace elements, which microalgae require for their cell growth. In addition, most of the microalgae are photosynthetic in nature, and these organisms do not require an organic source for their proliferation, although some strains could utilize organics both in the presence and absence of light. Therefore, microalgal bioremediation could be integrated with existing treatment methods or adopted as the single biological method for efficiently treating wastewater. This review paper summarized the mechanisms of pollutants removal by microalgae, microalgal bioremediation potential of different types of wastewaters, the potential application of wastewater-grown microalgal biomass, existing challenges, and the future direction of microalgal application in wastewater treatment.
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Lugo, Libardo A., Ragnheidur I. Thorarinsdottir, Sigfus Bjornsson, Olafur P. Palsson, Hakon Skulason, Skuli Johannsson, and Sigurdur Brynjolfsson. "Remediation of Aquaculture Wastewater Using the Microalga Chlorella sorokiniana." Water 12, no. 11 (November 10, 2020): 3144. http://dx.doi.org/10.3390/w12113144.
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The aquaculture industry requires solutions to several environmental challenges in order to become sustainable, including adequate wastewater management. Aquaculture wastewater (AWW) is rich in nitrogen, phosphorus, organic carbon, and other elements essential for microalgae. Due to the potential for AWW to be used as a microalgal growth medium and the potential of Chlorella sorokiniana to remediate wastewater, the growth of this species in AWW was evaluated. The microalgal growth in AWW was compared to the growth in a modified BG11 growth medium containing similar nutrient concentrations as the AWW. The effect of pH regulation and air-lifting the cell suspension at different airflow rates was also studied. As a result, it was found that C. sorokiniana can grow successfully in AWW; however, its cultivation required pH regulation. This microalga species can reach a biomass concentration of up to 476 mg/L and a biomass productivity of 140 mg/L/day. Furthermore, up to 78% of the nitrogen, 77% of the phosphorus, 70% of the magnesium, 90% of the zinc, and 99% of the nickel contained in the AWW were assimilated by the microalgae. The results of this study show that microalga cultivation in wastewater has great potential to reduce contamination while generating economic benefits.
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Lafarga, Tomás, Carlo Pieroni, Giuliana D’Imporzano, Lorenzo Maggioni, Fabrizio Adani, and Gabriel Acién. "Consumer Attitudes towards Microalgae Production and Microalgae-Based Agricultural Products: The Cases of Almería (Spain) and Livorno (Italy)." ChemEngineering 5, no. 2 (May 28, 2021): 27. http://dx.doi.org/10.3390/chemengineering5020027.
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The production of microalgal biomass and products derived thereof for a wide variety of applications is a hot research topic, with the number of facilities being built and products and biologically active molecules launched into the market increasing every year. The aim of the current study was to identify the attitudes of citizens in Almería (Spain) and Livorno (Italy) towards the construction of a microalgae production plant and a biorefinery in their cities and also their opinions about the microalgae-based products that could be produced. Overall, in Almería (Spain), a NIMBY (not in my back yard) attitude towards the construction of a microalgal production facility and especially towards a microalgal biorefinery was observed, despite the strong microalgal industry in the region and the higher knowledge of citizens about microalgae. In both locations, but especially in Livorno (Italy), microalgae-based biostimulants, biofertilisers, and aquafeeds were well accepted. Proximity was the main factor affecting the acceptance of a microalgae producing facility. Consumer knowledge about microalgal biotechnology and the health and environmental benefits of this valuable raw material are scarce, and opinions are based on drivers other than knowledge. After gaining more knowledge about microalgal biorefineries, most of the responses in Almería (47%) and Livorno (61%) were more positive.
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Mahata, Chandan, Probir Das, Shoyeb Khan, Mahmoud I. A. Thaher, Mohammed Abdul Quadir, Senthil Nagappan Annamalai, and Hareb Al Jabri. "The Potential of Marine Microalgae for the Production of Food, Feed, and Fuel (3F)." Fermentation 8, no. 7 (July 5, 2022): 316. http://dx.doi.org/10.3390/fermentation8070316.
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Whole-cell microalgae biomass and their specific metabolites are excellent sources of renewable and alternative feedstock for various products. In most cases, the content and quality of whole-cell biomass or specific microalgal metabolites could be produced by both fresh and marine microalgae strains. However, a large water footprint for freshwater microalgae strain is a big concern, especially if the biomass is intended for non-food applications. Therefore, if any marine microalgae could produce biomass of desired quality, it would have a competitive edge over freshwater microalgae. Apart from biofuels, recently, microalgal biomass has gained considerable attention as food ingredients for both humans and animals and feedstock for different bulk chemicals. In this regard, several technologies are being developed to utilize marine microalgae in the production of food, feed, and biofuels. Nevertheless, the production of suitable and cheap biomass feedstock using marine microalgae has faced several challenges associated with cultivation and downstream processing. This review will explore the potential pathways, associated challenges, and future directions of developing marine microalgae biomass-based food, feed, and fuels (3F).
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Xin, Yi, Shan Wu, Congcong Miao, Tao Xu, and Yandu Lu. "Towards Lipid from Microalgae: Products, Biosynthesis, and Genetic Engineering." Life 14, no. 4 (March 28, 2024): 447. http://dx.doi.org/10.3390/life14040447.
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Microalgae can convert carbon dioxide into organic matter through photosynthesis. Thus, they are considered as an environment-friendly and efficient cell chassis for biologically active metabolites. Microalgal lipids are a class of organic compounds that can be used as raw materials for food, feed, cosmetics, healthcare products, bioenergy, etc., with tremendous potential for commercialization. In this review, we summarized the commercial lipid products from eukaryotic microalgae, and updated the mechanisms of lipid synthesis in microalgae. Moreover, we reviewed the enhancement of lipids, triglycerides, polyunsaturated fatty acids, pigments, and terpenes in microalgae via environmental induction and/or metabolic engineering in the past five years. Collectively, we provided a comprehensive overview of the products, biosynthesis, induced strategies and genetic engineering in microalgal lipids. Meanwhile, the outlook has been presented for the development of microalgal lipids industries, emphasizing the significance of the accurate analysis of lipid bioactivity, as well as the high-throughput screening of microalgae with specific lipids.
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Sivaramakrishnan, Ramachandran, Subramaniyam Suresh, Simab Kanwal, Govindarajan Ramadoss, Balasubramani Ramprakash, and Aran Incharoensakdi. "Microalgal Biorefinery Concepts’ Developments for Biofuel and Bioproducts: Current Perspective and Bottlenecks." International Journal of Molecular Sciences 23, no. 5 (February 27, 2022): 2623. http://dx.doi.org/10.3390/ijms23052623.
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Microalgae have received much interest as a biofuel feedstock. However, the economic feasibility of biofuel production from microalgae does not satisfy capital investors. Apart from the biofuels, it is necessary to produce high-value co-products from microalgae fraction to satisfy the economic aspects of microalgae biorefinery. In addition, microalgae-based wastewater treatment is considered as an alternative for the conventional wastewater treatment in terms of energy consumption, which is suitable for microalgae biorefinery approaches. The energy consumption of a microalgae wastewater treatment system (0.2 kW/h/m3) was reduced 10 times when compared to the conventional wastewater treatment system (to 2 kW/h/m3). Microalgae are rich in various biomolecules such as carbohydrates, proteins, lipids, pigments, vitamins, and antioxidants; all these valuable products can be utilized by nutritional, pharmaceutical, and cosmetic industries. There are several bottlenecks associated with microalgae biorefinery. Hence, it is essential to promote the sustainability of microalgal biorefinery with innovative ideas to produce biofuel with high-value products. This review attempted to bring out the trends and promising solutions to realize microalgal production of multiple products at an industrial scale. New perspectives and current challenges are discussed for the development of algal biorefinery concepts.
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Kovačević, Goran, Daniela Petrinec, Petra Tramontana Ljubičić, Siegfried Reipert, Damir Sirovina, Maria Špoljar, Petra Peharec Štefanić, and Davor Želježić. "Formation of Microalgal Hunting Nets in Freshwater Microcosm Food Web: Microscopic Evidence." Water 15, no. 19 (September 30, 2023): 3448. http://dx.doi.org/10.3390/w15193448.
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The microcosm is a laboratory method frequently used in ecological studies related to population and food web interactions and environmental dynamics. It simultaneously brings into interaction different species in the same controlled laboratory experimental area and provides an opportunity for modeling and reconstruction of relationships in the natural biocenoses and ecosystems. We applied that approach to determine and improve our understanding of predator–prey interactions in different freshwater environments. The inhabitants of the microcosms were isolated endosymbiotic microalga Desmodesmus subspicatus (Chlorophyceae) (Chodat) Hegewald et Schmidt (CZ), green hydras, freshwater turbellarians, and large water fleas. Experiments were performed in five replicates, at 25 °C and 13.5 °C, with fed and hungry predators, respectively. Herein, we proposed a mechanism for microalgal hunting net formation in the freshwater microcosm. Ultrastructural visualization of the endosymbiotic microalgae revealed rod-like structures on the cell wall surface, structures that could possibly fit together and interconnect, suggesting the possibility of microalgal hunting net formation. Interspecific cooperation between isolated microalgae and turbellarians resulted in stronger hunting net formation in preying upon water fleas. This study contributes to the diversity of species interactions and shows the producers as a top link, as opposed to what is generally considered as a basic link in the food web, and presents the microalgae as triggers of the dynamics in the freshwater microcosm.
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Estime, Bendy, Dacheng Ren, and Radhakrishna Sureshkumar. "Tailored Fabrication of Plasmonic Film Light Filters for Enhanced Microalgal Growth and Biomass Composition." Nanomaterials 14, no. 1 (December 22, 2023): 44. http://dx.doi.org/10.3390/nano14010044.
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Through plasmon resonance, silver and gold nanoparticles can selectively backscatter light within different regions of the visible electromagnetic spectrum. We engineered a plasmonic film technology that utilizes gold and silver nanoparticles to enhance light at the necessary wavelengths for microalgal photosynthetic activities. Nanoparticles were embedded in a polymeric matrix to fabricate millimeter-thin plasmonic films that can be used as light filters in microalgal photobioreactors. Experiments conducted with microalga Chlamydomonas reinhardtii proved that microalgal growth and photosynthetic pigment production can be increased by up to 50% and 78%, respectively, by using these plasmonic film light filters. This work provides a scalable strategy for the efficient production of specialty chemicals and biofuels from microalgae through irradiation control with plasmonic nanoparticles.
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Sendzikiene, Egle, and Violeta Makareviciene. "Application of Liquid Waste from Biogas Production for Microalgae Chlorella sp. Cultivation." Cells 11, no. 7 (April 3, 2022): 1206. http://dx.doi.org/10.3390/cells11071206.
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Microalgae biomass is a viable feedstock for a wide range of industries. Recently, there has also been interest in the ability of microalgae biomass applications for biofuel production. In the meantime, the cultivation of microalgae biomass requires high energy costs, and the application of microalgae for technical purposes is still problematic. A significant part of the cost of biomass arises from the nutrients used for cultivation. Chemical compounds included in the microalgae cultivation media can be replaced by suitable wastes containing nitrogen, phosphorus, and other elements. This could reduce the microalgae biomass cultivation price and allow cheaper biomass to be used for biofuel production. The aim of this work was to comprehensively investigate and optimize the growth process of microalgae using liquid waste (liquid waste after biogas production from sewage sludge and distillers’ grain) as a source of nitrogen and phosphorus, and technical glycerol as a carbon source. It was found that higher levels of waste in the cultivation media were found to inhibit the accumulation of microalgal biomass, with the optimum level corresponding to a nitrogen concentration of 0.08 g/L. The influence of technical glycerol from biodiesel production on the yield of microalgal biomass was investigated, and it was found that the addition of 6% glycerol allows an increase in the concentration of microalgal biomass in the cultivation media, from 18.1 to 20.6%.
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Zhu, L. D., Z. H. Li, and E. Hiltunen. "Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock." BioMed Research International 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/8792548.
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In response to the energy crisis, global warming, and climate changes, microalgae have received a great deal of attention as a biofuel feedstock. Due to a high lipid content in microalgal cells, microalgae present as a promising alternative source for the production of biodiesel. Environmental and culturing condition variations can alter lipid production as well as chemical compositions of microalgae. Therefore, application of the strategies to activate lipid accumulation opens the door for lipid overproduction in microalgae. Until now, many original studies regarding the approaches for enhanced microalgal lipid production have been reported in an effort to push forward the production of microalgal biodiesel. However, the current literature demonstrates fragmented information available regarding the strategies for lipid production improvement. From the systematic point of view, the review highlights the main approaches for microalgal lipid accumulation induction to expedite the application of microalgal biodiesel as an alternative to fossil diesel for sustainable environment. Of the several strategies discussed, the one that is most commonly applied is the design of nutrient (e.g., nitrogen, phosphorus, and sulfur) starvation or limitation. Other viable approaches such as light intensity, temperature, carbon dioxide, salinity stress, and metal influence can also achieve enhanced microalgal lipid production.
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Jeevanandam, Jaison, Mohd Razif Harun, Sie Yon Lau, Divine D. Sewu, and Michael K. Danquah. "Microalgal Biomass Generation via Electroflotation: A Cost-Effective Dewatering Technology." Applied Sciences 10, no. 24 (December 18, 2020): 9053. http://dx.doi.org/10.3390/app10249053.
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Microalgae are an excellent source of bioactive compounds for the production of a wide range of vital consumer products in the biofuel, pharmaceutical, food, cosmetics, and agricultural industries, in addition to huge upstream benefits relating to carbon dioxide biosequestration and wastewater treatment. However, energy-efficient, cost-effective, and scalable microalgal technologies for commercial-scale applications are limited, and this has significantly impacted the full-scale implementation of microalgal biosystems for bioproduct development, phycoremediation, and biorefinery applications. Microalgae culture dewatering continues to be a major challenge to large-scale biomass generation, and this is primarily due to the low cell densities of microalgal cultures and the small hydrodynamic size of microalgal cells. With such biophysical characteristics, energy-intensive solid–liquid separation processes such as centrifugation and filtration are generally used for continuous generation of biomass in large-scale settings, making dewatering a major contributor to the microalgae bioprocess economics. This article analyzes the potential of electroflotation as a cost-effective dewatering process that can be integrated into microalgae bioprocesses for continuous biomass production. Electroflotation hinges on the generation of fine bubbles at the surface of an electrode system to entrain microalgal particulates to the surface. A modification of electroflotation, which combines electrocoagulation to catalyze the coalescence of microalgae cells before gaseous entrainment, is also discussed. A technoeconomic appraisal of the prospects of electroflotation compared with other dewatering technologies is presented.
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López-Pacheco, Itzel Y., Victoria Guadalupe Ayala-Moreno, Catherinne Arlette Mejia-Melara, José Rodríguez-Rodríguez, Sara P. Cuellar-Bermudez, Reyna Berenice González-González, Karina G. Coronado-Apodaca, et al. "Growth Behavior, Biomass Composition and Fatty Acid Methyl Esters (FAMEs) Production Potential of Chlamydomonas reinhardtii, and Chlorella vulgaris Cultures." Marine Drugs 21, no. 8 (August 15, 2023): 450. http://dx.doi.org/10.3390/md21080450.
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The production of biomolecules by microalgae has a wide range of applications in the development of various materials and products, such as biodiesel, food supplements, and cosmetics. Microalgae biomass can be produced using waste and in a smaller space than other types of crops (e.g., soja, corn), which shows microalgae’s great potential as a source of biomass. Among the produced biomolecules of greatest interest are carbohydrates, proteins, lipids, and fatty acids. In this study, the production of these biomolecules was determined in two strains of microalgae (Chlamydomonas reinhardtii and Chlorella vulgaris) when exposed to different concentrations of nitrogen, phosphorus, and sulfur. Results show a significant microalgal growth (3.69 g L−1) and carbohydrates (163 mg g−1) increase in C. reinhardtii under low nitrogen concentration. Also, higher lipids content was produced under low sulfur concentration (246 mg g−1). It was observed that sulfur variation could affect in a negative way proteins production in C. reinhardtii culture. In the case of C. vulgaris, a higher biomass production was obtained in the standard culture medium (1.37 g L−1), and under a low-phosphorus condition, C. vulgaris produced a higher lipids concentration (248 mg g−1). It was observed that a low concentration of nitrogen had a better effect on the accumulation of fatty acid methyl esters (FAMEs) (C16-C18) in both microalgae. These results lead us to visualize the effects that the variation in macronutrients can have on the growth of microalgae and their possible utility for the production of microalgae-based subproducts.
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Moreira, Juliana Botelho, Bruna da Silva Vaz, Bruna Barcelos Cardias, Camila Gonzales Cruz, Ana Claudia Araujo de Almeida, Jorge Alberto Vieira Costa, and Michele Greque de Morais. "Microalgae Polysaccharides: An Alternative Source for Food Production and Sustainable Agriculture." Polysaccharides 3, no. 2 (June 11, 2022): 441–57. http://dx.doi.org/10.3390/polysaccharides3020027.
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Carbohydrates or polysaccharides are the main products derived from photosynthesis and carbon fixation in the Calvin cycle. Compared to other sources, polysaccharides derived from microalgae are safe, biocompatible, biodegradable, stable, and versatile. These polymeric macromolecules present complex biochemical structures according to each microalgal species. In addition, they exhibit emulsifying properties and biological characteristics that include antioxidant, anti-inflammatory, antitumor, and antimicrobial activities. Some microalgal species have a naturally high concentration of carbohydrates. Other species can adapt their metabolism to produce more sugars from changes in temperature and light, carbon source, macro and micronutrient limitations (mainly nitrogen), and saline stress. In addition to growing in adverse conditions, microalgae can use industrial effluents as an alternative source of nutrients. Microalgal polysaccharides are predominantly composed of pentose and hexose monosaccharide subunits with many glycosidic bonds. Microalgae polysaccharides can be structural constituents of the cell wall, energy stores, or protective polysaccharides and cell interaction. The industrial use of microalgae polysaccharides is on the rise. These microorganisms present rheological and biological properties, making them a promising candidate for application in the food industry and agriculture. Thus, microalgae polysaccharides are promising sustainable alternatives for potential applications in several sectors, and the choice of producing microalgal species depends on the required functional activity. In this context, this review article aims to provide an overview of microalgae technology for polysaccharide production, emphasizing its potential in the food, animal feed, and agriculture sector.
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Ma, Chao, Bing Feng Liu, Hong Yu Ren, and Nan Qi Ren. "A Review on Biodiesel Production: Breeding Technologies of Microalgae Containing Rich Lipid." Applied Mechanics and Materials 472 (January 2014): 759–63. http://dx.doi.org/10.4028/www.scientific.net/amm.472.759.
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Among different biodiesel production technologies, microalgae biodiesel production has exhibited largest potential as an substitute of fossil fuels. Microalgae are effective photosynthetic microorganisms and ideal materials for biodiesel production because they have many advantages, such as the high lipid content, fast growth rate and good adaptability. Most key factor for the industrialization of microalgae biodiesel production is selecting the microalgae with rich lipid, which determines the production cost of microalgae biodiesel. The different breeding technologies of microalgae can significantly shorten the breeding time, reduce the production cost and obtain expected strains. The prospect of microalgael application in biodiesel production was also discussed.
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Sahni, Prashant, Poonam Aggarwal, Savita Sharma, and Baljit Singh. "Nuances of microalgal technology in food and nutraceuticals: a review." Nutrition & Food Science 49, no. 5 (September 9, 2019): 866–85. http://dx.doi.org/10.1108/nfs-01-2019-0008.
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PurposeThe purpose of this paper is to acquaint the readers with the insights regarding the interventions of microalgal technology for production of metabolites and functional ingredients from microalgae for food and nutraceutical application and exploration of microalgae biomass for food application.Design/methodology/approachVarious information databases such as journals, library catalogues and professional websites were used to collect information pertaining to application of microalgae in food and nutraceutical sector. Systematic review was made with recent studies covering the vital aspects of art of microalgae cultivation for metabolite production, functional ingredients from microalgae, market scenario and utilisation of microalgae biomass for the valorisation of the food products. Key points have been discussed after every section to highlight the practical implications to make this review more insightful for the readers.FindingsMicroalgal technology provides sustainable solution for its application in food and nutraceutical sector. The heart of metabolite production lies in the optimisation of cultivation conditions of microalgae. Wide array of functional components are obtained from microalgae. Microalgae offer an alternative source for omega-3 fatty acids. Microalgae is widely exploited for production of pigments, namely, ß-carotene, astaxanthin, lutein, phycocyanin and chlorophyll, that have important implication as natural colourants and nutraceuticals in food. Larger diversity of sterols found in microalgae confers bioactivity. Microalgae is finding its place in market shelves as nutraceuticals where its functional ingredients are in the form of powder, tablets, extract and beverages and in innovative products such as microalgae protein and fat, culinary algae oil and butter. Sprulina and Chlorella are popular choice for the supplementation of food products with microalgae biomass.Originality/valueThis is a comprehensive review that highlights the application of microalgal technology for the development of healthy food products and presents holistic intervention in food and nutraceutical sector.
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Reis, Daiane Felix, Francisco Roberto da Silva Machado Junior, Joana Da Costa Ores, Ailton Cesar Lemes, Carlos Andre Veiga Burkert, and Janaina Fernandes de Medeiros Burkert. "Influência do CO2 no Crescimento de Haematococcus Pluvialis e na Produção de Carotenoides." UNICIÊNCIAS 22, no. 3Esp (January 24, 2019): 25. http://dx.doi.org/10.17921/1415-5141.2018v22n3espp25-29.
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O crescimento celular da microalga de água doce Haematococcus pluvialis e a bioprodução de carotenoides são influenciados pelas diferentes condições de cultivo, como deficiência de nutrientes, iluminância, aeração, agitação, temperatura e pH, alterando sua morfologia celular e produzindo cistos avermelhados (carotenogênese). A aeração nos cultivos de microalgas está relacionada a alguns fatores que influenciam no crescimento celular. As microalgas absorvem e utilizam CO2 como a principal fonte de carbono no crescimento celular. Logo, a biossíntese de pigmentos pode ocorrer pela limitação do nitrogênio em presença de excesso de fontes de carbono. O objetivo desse trabalho foi investigar a influência do emprego de CO2 na aeração do cultivo da microalga Haematococcus pluvialis sob o crescimento celular e a bioprodução de carotenoides. No cultivo foi utilizado o meio mixotrófico BBM (Bold Basal Medium) e acetato de sódio, empregando 20% de inóculo em pH inicial de 7,0, aeração de 0,30 L.min-1, com 30% de injeção de CO2 uma vez ao dia durante 1 h, sob iluminância de 6 klux, à 25 ºC durante 22 dias. Nestas condições o crescimento celular alcançou o máximo de 1,13±0,39 g.L-1 (10 dias) e os carotenoides totais 2949,91±988,65 µg.g-1, onde foi observado que a suplementação de CO2 como fonte de carbono dissolvida no meio de cultivo pode influenciar o crescimento celular e os carotenoides totais. Palavras-chave: Microalga. Pigmento. Aeração. Cultivo. AbstractThe cellular growth of the freshwater microalgae Haematococcus pluvialis and the bioproduction of carotenoids are influenced by the different culture conditions, such as nutrient deficiency, illuminance, aeration, agitation, temperature and pH, altering its cellular morphology and producing reddish cysts (carotenogenesis). Aeration in microalgae cultures is related to some factors that influence cell growth. Microalgae absorb and utilize CO2 as the main source of carbon in cell growth. Therefore, the biosynthesis of pigments can occur by the limitation of nitrogen in the presence of excess carbon sources. The objective of this work was to investigate the influence of the use of CO2 on the aeration of the microalgae Haematococcus pluvialis under cell growth and bioproduction of carotenoids. In the culture, mixotrophic medium BBM (Bold Basal Medium) and sodium acetate were used, using 20% of inoculum at initial pH of 7.0, aeration of 0.30 L.min-1, with 30% of CO2 injection once a day for 1 h under 6 Klux illuminance at 25 ° C for 22 days. Under these conditions the cell growth reached a maximum of 1.13 ± 0.39 g. L-1 (10 days) and the total carotenoids 2949.91 ± 988.65 μg.g-1, where it was observed that CO2 supplementation as a source of carbon dissolved in the culture medium may influence cell growth and total carotenoids. Keywords: microalgae; pigment; aeration; cultivation.
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Ávila-Román, Javier, Elena Talero, Antonio Alcaide, Carolina de los Reyes, Eva Zubía, Sofía García-Mauriño, and Virginia Motilva. "Preventive effect of the microalgaChlamydomonas debaryanaon the acute phase of experimental colitis in rats." British Journal of Nutrition 112, no. 7 (September 5, 2014): 1055–64. http://dx.doi.org/10.1017/s0007114514001895.
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Inflammatory bowel diseases (IBD) are characterised by chronic uncontrolled inflammation of intestinal mucosa. Diet and nutritional factors have emerged as possible interventions for IBD. Microalgae are rich sources ofn-3 PUFA and derived oxylipins. Oxylipins are lipid mediators involved in the resolution of many inflammatory disorders. The aim of the present study was to investigate the effects of the oxylipin-containing biomass of the microalgaChlamydomonas debaryanaand its major oxylipin constituent, (9Z,11E,13S,15Z)-13-hydroxyoctadeca-9,11,15-trienoic acid ((13S)-HOTE), on acute 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis in rats. Lyophilised microalgal biomass and (13S)-HOTE were administered by oral route 48, 24 and 1 h before the induction of colitis and 24 h later, and the rats were killed after 48 h. The treatment with the lyophilised microalga and (13S)-HOTE improved body-weight loss and colon shortening, as well as attenuated the extent of colonic damage and increased mucus production. Cellular neutrophil infiltration, with the subsequent increase in myeloperoxidase levels induced by TNBS, were also reduced after the administration of the lyophilised microalga or (13S)-HOTE. The anti-inflammatory effects of these treatments were confirmed by the inhibition of colonic TNF-α production. Moreover, lyophilised microalga or (13S)-HOTE down-regulated cyclo-oxygenase-2 and inducible nitric oxide synthase expression. The present study was the first to show the prophylactic effects of a lyophilised biomass sample of the microalgaC. debaryanaand the oxylipin (13S)-HOTE on TNBS-induced acute colitis in rats. Our findings suggest that the microalgaC. debaryanaor derived oxylipins could be used as nutraceuticals in the treatment of the active phase of IBD.
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Bleisch, Richard, Leander Freitag, Yob Ihadjadene, Una Sprenger, Juliane Steingröwer, Thomas Walther, and Felix Krujatz. "Strain Development in Microalgal Biotechnology—Random Mutagenesis Techniques." Life 12, no. 7 (June 27, 2022): 961. http://dx.doi.org/10.3390/life12070961.
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Microalgal biomass and metabolites can be used as a renewable source of nutrition, pharmaceuticals and energy to maintain or improve the quality of human life. Microalgae’s high volumetric productivity and low impact on the environment make them a promising raw material in terms of both ecology and economics. To optimize biotechnological processes with microalgae, improving the productivity and robustness of the cell factories is a major step towards economically viable bioprocesses. This review provides an overview of random mutagenesis techniques that are applied to microalgal cell factories, with a particular focus on physical and chemical mutagens, mutagenesis conditions and mutant characteristics.
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Song, Yanhui, Fangzhong Wang, Lei Chen, and Weiwen Zhang. "Engineering Fatty Acid Biosynthesis in Microalgae: Recent Progress and Perspectives." Marine Drugs 22, no. 5 (May 9, 2024): 216. http://dx.doi.org/10.3390/md22050216.
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Microalgal lipids hold significant potential for the production of biodiesel and dietary supplements. To enhance their cost-effectiveness and commercial competitiveness, it is imperative to improve microalgal lipid productivity. Metabolic engineering that targets the key enzymes of the fatty acid synthesis pathway, along with transcription factor engineering, are effective strategies for improving lipid productivity in microalgae. This review provides a summary of the advancements made in the past 5 years in engineering the fatty acid biosynthetic pathway in eukaryotic microalgae. Furthermore, this review offers insights into transcriptional regulatory mechanisms and transcription factor engineering aimed at enhancing lipid production in eukaryotic microalgae. Finally, the review discusses the challenges and future perspectives associated with utilizing microalgae for the efficient production of lipids.
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de-Bashan, Luz E., Yoav Bashan, Manuel Moreno, Vladimir K. Lebsky, and Jose J. Bustillos. "Increased pigment and lipid content, lipid variety, and cell and population size of the microalgae Chlorella spp. when co-immobilized in alginate beads with the microalgae-growth-promoting bacterium Azospirillum brasilense." Canadian Journal of Microbiology 48, no. 6 (June 1, 2002): 514–21. http://dx.doi.org/10.1139/w02-051.
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Three strains of the freshwater microalgae used for wastewater treatment, Chlorella vulgaris and Chlorella sorokiniana co-immobilized separately in alginate beads with the microalgae-growth-promoting bacterium Azospirillum brasilense Cd, resulted in significant changes in microalgal-population size, cell size, cell cytology, pigment, lipid content, and the variety of fatty acids produced in comparison with microalgae immobilized in alginate without the bacterium. Cells of C. vulgaris UTEX 2714 did not change in size, but the population size within the beads significantly increased. On the other hand, C. vulgaris UTEX 395 cells grew 62% larger, but their numbers did not increase. The population of C. sorokiniana UTEX 1602 increased, but not their cell size. The content of pigments chlorophyll a andb, lutein, and violoaxanthin increased in all microalgal species. The lipid content also significantly increased in all three strains, and the number of different fatty acids in the microalgae increased from four to eight. This study indicates that the microalgae-growth-promoting bacterium induced significant changes in the metabolism of the microalgae.Key words: alginate, Azospirillum, Chlorella, bacterial immobilization, microalgae, wastewater.
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Xu, Yun Yun, Tao Zhang, Lei Chen, Zhen Rong Lin, and Xiao Yu Ge. "Biologically Active Compounds from Microalgae and its Health Function." Advanced Materials Research 554-556 (July 2012): 1709–12. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.1709.
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Microalgae are a biochemically diverse assemblage of microorganisms amenable to fermentation and mass culture.Most of these microalgae species produce unique products like carotenoids，antioxidants，fatty acids，enzymes，polymers，peptides，toxins and sterols.Microalgae might become economic sources of new drugs，other specialty chemicals and functional foods because production can be optimized in controlled culture.This paper introduced the biologically active compounds from microalgae and its health function，studies of microalgae in human nutrition and new trends in microalgae food，researched on microalgal health food，and the development of information was provided.
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Araújo, Fabíola Ornellas de, Reinaldo Giudici, and João José Martins Simões de Sousa. "CULTIVATION OF THE MICROALGAE CHLORELLA PYRENOIDOSA USING THE PROCESSES OF BIOTECHNOLOGY." Revista Eletrônica Acervo Científico 2 (March 26, 2019): 121. http://dx.doi.org/10.25248/reac.e121.2019.
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The results obtained here, show that the use of Chlorella pyrenoidosa microalgae and biotechnology, using the discontinuous process, presented satisfactory results. With this, the study of the microalga Chlorella sp. has proved to be important because it has a wealth of proteins, carbohydrates, amino acids, fatty acids, carotenoids, vitamins and minerals in its constitution, which may represent commercial importance. This research revealed the best results for obtaining a lipoprotein-rich biomass, taking into account three different culture media, calculations of cell concentration, cell productivity, to the content (%) of protein, lipid, carbohydrate and ash present in the microalgal biomass.
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Grama, Samir B., Zhiyuan Liu, and Jian Li. "Emerging Trends in Genetic Engineering of Microalgae for Commercial Applications." Marine Drugs 20, no. 5 (April 24, 2022): 285. http://dx.doi.org/10.3390/md20050285.
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Recently, microalgal biotechnology has received increasing interests in producing valuable, sustainable and environmentally friendly bioproducts. The development of economically viable production processes entails resolving certain limitations of microalgal biotechnology, and fast evolving genetic engineering technologies have emerged as new tools to overcome these limitations. This review provides a synopsis of recent progress, current trends and emerging approaches of genetic engineering of microalgae for commercial applications, including production of pharmaceutical protein, lipid, carotenoids and biohydrogen, etc. Photochemistry improvement in microalgae and CO2 sequestration by microalgae via genetic engineering were also discussed since these subjects are closely entangled with commercial production of the above mentioned products. Although genetic engineering of microalgae is proved to be very effective in boosting performance of production in laboratory conditions, only limited success was achieved to be applicable to industry so far. With genetic engineering technologies advancing rapidly and intensive investigations going on, more bioproducts are expected to be produced by genetically modified microalgae and even much more to be prospected.
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Barolo, Lorenzo, Raffaela M. Abbriano, Audrey S. Commault, Jestin George, Tim Kahlke, Michele Fabris, Matthew P. Padula, Angelo Lopez, Peter J. Ralph, and Mathieu Pernice. "Perspectives for Glyco-Engineering of Recombinant Biopharmaceuticals from Microalgae." Cells 9, no. 3 (March 5, 2020): 633. http://dx.doi.org/10.3390/cells9030633.
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Microalgae exhibit great potential for recombinant therapeutic protein production, due to lower production costs, immunity to human pathogens, and advanced genetic toolkits. However, a fundamental aspect to consider for recombinant biopharmaceutical production is the presence of correct post-translational modifications. Multiple recent studies focusing on glycosylation in microalgae have revealed unique species-specific patterns absent in humans. Glycosylation is particularly important for protein function and is directly responsible for recombinant biopharmaceutical immunogenicity. Therefore, it is necessary to fully characterise this key feature in microalgae before these organisms can be established as industrially relevant microbial biofactories. Here, we review the work done to date on production of recombinant biopharmaceuticals in microalgae, experimental and computational evidence for N- and O-glycosylation in diverse microalgal groups, established approaches for glyco-engineering, and perspectives for their application in microalgal systems. The insights from this review may be applied to future glyco-engineering attempts to humanize recombinant therapeutic proteins and to potentially obtain cheaper, fully functional biopharmaceuticals from microalgae.
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Rajagopal, Rajinikanth, Seyyed Ebrahim Mousavi, Bernard Goyette, and Suman Adhikary. "Coupling of Microalgae Cultivation with Anaerobic Digestion of Poultry Wastes: Toward Sustainable Value Added Bioproducts." Bioengineering 8, no. 5 (May 4, 2021): 57. http://dx.doi.org/10.3390/bioengineering8050057.
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Third generation biofuels and high-value bioproducts produced from microalgal biomass have been considered promising long-term sustainable alternatives for energy and/or food production, potentially decreasing greenhouse gas emissions. Microalgae as a source of biofuels have been widely studied for bioethanol/biodiesel/biogas production. However, critical research is needed in order to increase the efficiency of microalgae production from high-N agri-waste, not only for biofuels but also for bio-based products, and thus enhance its commercial viability. The growth in the poultry industry has led to increased chicken manure (CM), which are rich in ammonia, phosphate, potassium, and other trace elements. These constituents could be used as nutrients for growing microalgae. In this research, a two-stage (liquid–solid) anaerobic digester treating CM at 20 ± 1 °C was performed, and liquid digestate (leachate) obtained after the digestion process was used as a substrate to grow the microalgal strain Chlorella vulgaris CPCC 90. Considering the high-N content (NH3-N: 5314 mg/L; TKN: 6197 mg/L) in liquid digestate, different dilutions were made, using distilled water to obtain viz. 10%, 30%, 50%, 70%, 90%, and 100% of the digestate concentrations for the microalgae cultivation. Preliminary results showed that Chlorella vulgaris CPCC 90 was able to grow and utilize nutrients from a 10% diluted CM digestate. Future research is underway to enhance microalgal growth at higher digestate concentrations and to optimize the use of microalgae/microalgae-bacteria consortia for better adaptation to high-N content wastes. An AD-microalgae coupling scenario has been proposed for the circulation bioeconomy framework.
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de Morais, Michele Greque, Bruna da Silva Vaz, Etiele Greque de Morais, and Jorge Alberto Vieira Costa. "Biologically Active Metabolites Synthesized by Microalgae." BioMed Research International 2015 (2015): 1–15. http://dx.doi.org/10.1155/2015/835761.
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Microalgae are microorganisms that have different morphological, physiological, and genetic traits that confer the ability to produce different biologically active metabolites. Microalgal biotechnology has become a subject of study for various fields, due to the varied bioproducts that can be obtained from these microorganisms. When microalgal cultivation processes are better understood, microalgae can become an environmentally friendly and economically viable source of compounds of interest, because production can be optimized in a controlled culture. The bioactive compounds derived from microalgae have anti-inflammatory, antimicrobial, and antioxidant activities, among others. Furthermore, these microorganisms have the ability to promote health and reduce the risk of the development of degenerative diseases. In this context, the aim of this review is to discuss bioactive metabolites produced by microalgae for possible applications in the life sciences.
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Rahman, Md Mijanur, Nushin Hosano, and Hamid Hosano. "Recovering Microalgal Bioresources: A Review of Cell Disruption Methods and Extraction Technologies." Molecules 27, no. 9 (April 27, 2022): 2786. http://dx.doi.org/10.3390/molecules27092786.
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Microalgae have evolved into a promising sustainable source of a wide range of compounds, including protein, carbohydrates, biomass, vitamins, animal feed, and cosmetic products. The process of extraction of intracellular composites in the microalgae industry is largely determined by the microalgal species, cultivation methods, cell wall disruption techniques, and extraction strategies. Various techniques have been applied to disrupt the cell wall and recover the intracellular molecules from microalgae, including non-mechanical, mechanical, and combined methods. A comprehensive understanding of the cell disruption processes in each method is essential to improve the efficiency of current technologies and further development of new methods in this field. In this review, an overview of microalgal cell disruption techniques and an analysis of their performance and challenges are provided. A number of studies on cell disruption and microalgae extraction are examined in order to highlight the key challenges facing the field of microalgae and their future prospects. In addition, the amount of product recovery for each species of microalgae and the important parameters for each technique are discussed. Finally, pulsed electric field (PEF)-assisted treatments, which are becoming an attractive option due to their simplicity and effectiveness in extracting microalgae compounds, are discussed in detail.
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López-Hernández, Jenny Fabiola, Pedro García-Alamilla, Diana Palma-Ramírez, Carlos Alfonso Álvarez-González, Juan Carlos Paredes-Rojas, and Facundo J. Márquez-Rocha. "Continuous Microalgal Cultivation for Antioxidants Production." Molecules 25, no. 18 (September 11, 2020): 4171. http://dx.doi.org/10.3390/molecules25184171.
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Microalgae, including cyanobacteria, represent a valuable source of natural compounds that have remarkable bioactive properties. Each microalga species produces a mixture of antioxidants with different amounts of each compound. Three aspects are important in the production of bioactive compounds: the microalga species, the medium composition including light supplied and the photobioreactor design, and operation characteristics. In this study, the antioxidant content and productivity performance of four microalgae were assessed in batch and continuous cultures. Biomass productivity by the four microalgae was substantially enhanced under continuous cultivation by 5.9 to 6.3 times in comparison with batch cultures. The energetic yield, under the experimental conditions studied, ranged from 0.03 to 0.041 g biomass kJ−1. Phenols, terpenoids, and alkaloids were produced by Spirulinaplatensis, Isochrysisgalbana, and Tetraselmissuecica, whereas tocopherols and carotenoids were produced by the four microalgae, except for phycocyanin and allophycocyanin, which were only produced by S. platensis and Porphyridiumcruentum. The findings demonstrate that the continuous cultivation of microalgae in photobioreactors is a convenient method of efficiently producing antioxidants.
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Branyikova, Irena, Gita Prochazkova, Tomas Potocar, Zuzana Jezkova, and Tomas Branyik. "Harvesting of Microalgae by Flocculation." Fermentation 4, no. 4 (November 9, 2018): 93. http://dx.doi.org/10.3390/fermentation4040093.
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Due to increasing demands for microalgal biomass and products originating from microalgae, large-scale production systems are necessary. However, current microalgal production technologies are not cost-effective and are hindered by various bottlenecks, one of which is the harvesting of microalgal biomass. Cell separation is difficult because of the low sedimentation velocity of microalgae, their colloidal character with repelling negative surface charges, and low biomass concentrations in culture broths; therefore, large volumes need to be processed in order to concentrate the cells. Flocculation is considered to be one of the most suitable methods for harvesting microalgal biomass. This article provides an overview of flocculation methods suitable for microalgal harvesting, their mechanisms, advantages and drawbacks. Special attention is paid to the role of surface charge in the mechanism of flocculation. The novelty of the review lies in the interconnection between the context of technological applications and physico-chemical surface phenomena.
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Tesson, Sylvie V. M., Carsten Ambelas Skjøth, Tina Šantl-Temkiv, and Jakob Löndahl. "Airborne Microalgae: Insights, Opportunities, and Challenges." Applied and Environmental Microbiology 82, no. 7 (January 22, 2016): 1978–91. http://dx.doi.org/10.1128/aem.03333-15.
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ABSTRACTAirborne dispersal of microalgae has largely been a blind spot in environmental biological studies because of their low concentration in the atmosphere and the technical limitations in investigating microalgae from air samples. Recent studies show that airborne microalgae can survive air transportation and interact with the environment, possibly influencing their deposition rates. This minireview presents a summary of these studies and traces the possible route, step by step, from established ecosystems to new habitats through air transportation over a variety of geographic scales. Emission, transportation, deposition, and adaptation to atmospheric stress are discussed, as well as the consequences of their dispersal on health and the environment and state-of-the-art techniques to detect and model airborne microalga dispersal. More-detailed studies on the microalga atmospheric cycle, including, for instance, ice nucleation activity and transport simulations, are crucial for improving our understanding of microalga ecology, identifying microalga interactions with the environment, and preventing unwanted contamination events or invasions.
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Ma, Ruijuan, Baobei Wang, Elvis T. Chua, Xurui Zhao, Kongyong Lu, Shih-Hsin Ho, Xinguo Shi, et al. "Comprehensive Utilization of Marine Microalgae for Enhanced Co-Production of Multiple Compounds." Marine Drugs 18, no. 9 (September 16, 2020): 467. http://dx.doi.org/10.3390/md18090467.
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Marine microalgae are regarded as potential feedstock because of their multiple valuable compounds, including lipids, pigments, carbohydrates, and proteins. Some of these compounds exhibit attractive bioactivities, such as carotenoids, ω-3 polyunsaturated fatty acids, polysaccharides, and peptides. However, the production cost of bioactive compounds is quite high, due to the low contents in marine microalgae. Comprehensive utilization of marine microalgae for multiple compounds production instead of the sole product can be an efficient way to increase the economic feasibility of bioactive compounds production and improve the production efficiency. This paper discusses the metabolic network of marine microalgal compounds, and indicates their interaction in biosynthesis pathways. Furthermore, potential applications of co-production of multiple compounds under various cultivation conditions by shifting metabolic flux are discussed, and cultivation strategies based on environmental and/or nutrient conditions are proposed to improve the co-production. Moreover, biorefinery techniques for the integral use of microalgal biomass are summarized. These techniques include the co-extraction of multiple bioactive compounds from marine microalgae by conventional methods, super/subcritical fluids, and ionic liquids, as well as direct utilization and biochemical or thermochemical conversion of microalgal residues. Overall, this review sheds light on the potential of the comprehensive utilization of marine microalgae for improving bioeconomy in practical industrial application.