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Sample records for cadmio sobre microalgas

  1. Efecto de la quercetina sobre la nefrotoxicidad producida por cadmio

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    A. I. Morales Martín

    2004-01-01

    Full Text Available El incremento en la producción anual de cadmio ha favorecido que la incidencia de la intoxicación crónica por este elemento haya aumentado en los últimos años. El estrés oxidativo es uno de los mecanismos implicados en la generación del efecto tóxico, manifestándose, entre otras patologías, por una disfunción y lesión renal. La quercetina, un flavonoide muy abundante en la dieta mediterránea, es un potente antioxidante y un buen quelante de metales. Nuestro objetivo fue estudiar si la administración de quercetina pudiera prevenir la aparición de los procesos nefrotóxicos asociados a la exposición crónica al cadmio. Los experimentos se realizaron con ratas Wistar (200g, incluidas en tres grupos experimentales: 1 ratas a las que se administró cadmio (1,2 mg/kg/día, s.c. cinco veces por semana, durante nueve semanas, 2 ratas a las cuales se les administró quercetina (50 mg/kg/día, i.p. cinco veces por semana, empezando en la cuarta semana y 3 ratas a las que se administró cadmio y quercetina. La lesión renal se evaluó midiendo proteinuria, microalbuminuria y glucosuria, así como la excreción de enzimas urinarias N-acetil-beta-D-glucosaminidasa, fosfatasa alcalina y gamma-glutamil-transpeptidasa. Las muestras de plasma se utilizaron para la determinación de creatinina y nitrógeno ureico plasmático, así como dialdehido malónico, como índice de peroxidación lipídica y antioxidantes totales en plasma. En riñón se midió la actividad enzimática de la superóxido dismutasa y de la glutation reductasa. Nuestros resultados mostraron que la administración de cadmio durante 9 semanas produjo un incremento en los valores de flujo urinario, proteinuria, microalbuminuria y glucosuria. El tratamiento con cadmio incluso incrementó la creatinina sérica y el nitrógeno uréico plasmático y elevó drásticamente la actividad de enzimas urinarias. Finalmente el aclaramiento de creatinina disminuyó como consecuencia de la

  2. Efecto de la quercetina sobre la nefrotoxicidad producida por cadmio

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    A. I. Morales Martín; Vicente Sánchez; C. Santiago Sandoval; J Mª Fernández Tagarro; J.M. López Novoa; F. Pérez Barriocanal

    2004-01-01

    El incremento en la producción anual de cadmio ha favorecido que la incidencia de la intoxicación crónica por este elemento haya aumentado en los últimos años. El estrés oxidativo es uno de los mecanismos implicados en la generación del efecto tóxico, manifestándose, entre otras patologías, por una disfunción y lesión renal. La quercetina, un flavonoide muy abundante en la dieta mediterránea, es un potente antioxidante y un buen quelante de metales. Nuestro objetivo fue estudia...

  3. EFECTO DEL pH EN LA ADSORCIÓN DE CADMIO, NÍQUEL Y ZINC SOBRE UNA BENTONITA

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    Liz Adriana Pinilla Cuesta

    2010-11-01

    Full Text Available Se estudió el efecto del pH sobre la adsorción de cadmio, niquel y zinc, en solución acuosa a 25"C, sobre una bentonita colombiana proveniente del Valle del Cauca. Los datos experimentales se analizaron con base en las isotermas de adsorción, la constante termodinámica de reparto Kdm (calculada mediante la isoterma de Langmuir, la relación de distribución Rd (obtenida del modelo Baeyens-Bradbury y una gráfica Kurbatov. La adsorción de cadmio, niquel y zinc aumenta con el pH. El orden de adsorción encontrado: Cd > Ni≅Zn coincide con el establecido por el principio HSAB.

  4. Efecto del pH en la adsorción de cadmio, niquel y zinc sobre una bentonita

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    Liz Adriana Pinilla Cuenca

    2010-09-01

    Full Text Available Se estudió el efecto del pH sobre la adsorción de cadmio, niquel y zinc, en solución acuosa a 25°C, sobre una bentonita colombiana proveniente del Valle del Cauca. Los datos experimentales se analizaron con base en las isotermas de adsorción, la constante termodinámica de reparto KDM (calculada mediante la isoterma de Langmuir, la relación de distribución Rd (obtenida del modelo Baeyens-Bradbury y una gráfica Kurbatov.

  5. Efecto del cobre y del cadmio sobre la respuesta inmune innata del pez Colossoma macropomum

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    A. Vargas

    2012-01-01

    Full Text Available En este trabajo se evaluó la respuesta inmunológica celular inespecífica del pez Colossoma macropomum (Cuvier, 1818 expuesto a concentraciones subletales de cobre y cadmio, a través de la determinación de la viabilidad celular, la quimiotaxis, la fagocitosis y la muerte bacteriana en células inmunocompetentes extraídas del riñón cefálico, la sangre y el hígado. Los peces fueron expuestos por separado a 0,5 mg/L de cloruro de cobre y 1,0 mg/L de cloruro de cadmio durante 28 días; después de la exposición, se depuraron por el mismo período. La viabilidad celular se mantuvo entre 99-94%. La exposición al cadmio causó una reducción significativa en la respuesta quimiotáctica de granulocitos en los tejidos evaluados. Tanto los peces expuestos a cobre como los expuestos a cadmio presentaron una disminución significativa en la respuesta fagocítica de granulocitos. En sangre, el cadmio afectó la efectividad de los granulocitos de inducir muerte bacteriana; el cobre sin embargo, afectó la efectividad de inducir muerte bacteriana en los granulocitos provenientes del hígado. Los peces expuestos a cadmio presentaron un incremento significativo en los niveles de cortisol sérico y una disminución de esta hormona en los peces expuestos a cobre. Estos resultados demuestran que la exposición crónica a los metales cobre y cadmio produce una inhibición de la respuesta inmune inespecífica en el pez Colossoma macropomum.

  6. Toxicidad del Cadmio en Plantas

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    M. Rodríquez-Serrano

    2008-01-01

    Full Text Available El cadmio es un metal pesado no esencial y poco abundante en la corteza terrestre, sin embargo en las últimas décadas ha aumentadoconsiderablemente su acumulación, como consecuencia de la actividad industrial. La contaminación por cadmio puede causar serios problemas a todos los organismos vivos, resultando altamente tóxico para el ser humano. Una posible fuente de contaminación por cadmio en humanos es la ingesta de plantas contaminadas por el metal. Por este motivo, es importante conocer cuales son los mecanismos de toxicidad del metal en la planta, así como los mecanismos de defensa de la misma. En este trabajo, se ha realizado una revisión de las principales fuentes de contaminación por cadmio, de la toxicidad del metal y de los mecanismos de hiperacumulación y fitoextracción de cadmio.

  7. toxicidad neuroendocrina inducida por cadmio

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    A Romero

    2008-01-01

    Full Text Available El cadmio es un agente químico tóxico importante debido a su creciente nivel en el medio ambiente como resultado de prácticas industriales y agrícolas. Como perturbador endocrino, el cadmio modifica la secreción de hormonas hipofisarias. Los efectos indirectos del cadmio provocan la generación de especies reactivas de oxígeno y reducen la actividad de las proteínas implicadas en las defensas antioxidantes. La melatonina es conocida como un potente antioxidante, scavenger de radicales libres y quelante de metales sintetizada en la glándula pineal. De esta manera, las acciones antioxidantes de esta indolamina protegen frente a la peroxidación lipídica y el daño oxidativo de los radicales y de sus productos tóxicos. Los trabajos recopilados en esta revisión ponen de manifiesto la capacidad antioxidante de la melatonina y, por lo tanto, su posible papel protector frente a la toxicidad del cadmio en lo que se refiere al estrés oxidativo y peroxidación lipídica inducidos por la exposición a este metal.

  8. Efecto de la fertilización fosforada sobre el contenido de cadmio en cuatro suelos de Chile Effect of phosphate fertilizer on the soil cadmium content in four types of Chilean soils

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    Claudia Bonomelli

    2003-10-01

    Full Text Available Los fertilizantes fosforados pueden contener cadmio (Cd y al utilizarlos pueden entrar en las cadenas tróficas. El objetivo de este estudio fue evaluar el efecto de la fertilización fosforada sobre la concentración de Cd disponible en cuatro tipos de suelos de Chile, que pertenecían a los ordenes Inceptisol, Alfisol, Ultisol y Andisol. Los dos tratamientos usados fueron el testigo sin fertilización y la aplicación de una dosis de corrección con un fertilizante comercial, superfosfato triple (SFT, que tenía una concentración de 53,2 mg de Cd por kg de fertilizante. La dosis de fertilizante aplicada fue la necesaria para alcanzar un nivel de 30 mg kg-1 de POlsen. Los suelos se incubaron en estufa durante 90 días, a 25ºC y humedad de capacidad de campo. El diseño experimental fue completamente al azar, con tres repeticiones para cada suelo y donde la unidad experimental fue un contenedor con 250 g de suelo seco. Se midió Cd disponible a los 1, 2, 7, 14, 21, 36, 49, 63, 77 y 90 días después de la incubación. La aplicación de P en dosis agronómica, utilizando fertilizante con alto contenido de Cd, tuvo un efecto estadísticamente significativo sobre la concentración de Cd disponible en los suelos estudiados, sin embargo, no hubo efecto del tiempo de incubación en la disponibilidad de Cadmio.Phosphate fertilizers may contain cadmiun (Cd which may become part of the trophic chains. The objective of this study was to evaluate the effect of phosphate fertilizer on available Cd content in four Chilean soil types, belonging to orders Alfisol, Inceptisol, Ultisol and Andisol. Treatments consisted of control without P fertilizer and P application with commercial triple superphosphate containing 53.2 mg Cd per kg of fertilizer. The dose of phosphate fertilizer applied was enough to reach the level of 30 mg kg-1 POlsen. The soils were incubated up to 90 days, at 25ºC and field capacity. The experimental design was completely randomized

  9. Preliminary observations of cadmium and copper effects on juveniles of the polychaete Capitella sp. Y (Annelida: Polychaeta from Estero del Yugo, Mazatlán, México Observaciones preliminares de los efectos de cadmio y cobre sobre juveniles del poliqueto Capitella sp. Y (Annelida: Polychaeta del Estero del Yugo, Mazatlán, México

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    NURIA MÉNDEZ

    2005-12-01

    Full Text Available The effects of cadmium (Cd and copper (Cu on cultured juveniles of Capitella sp. Y were investigated. Seven-day old juveniles were exposed to 13 (control, 60, 160, 240 and 340 mg Cd L-1 and 17 (control, 50, 120 and 150 mg Cu L-1 for 30 days. Mortality significantly increased with increasing Cu concentrations, but in Cd exposures, it was only evident at 340 mg L-1. Body size and faecal pellet production were reduced earlier in juveniles exposed to Cu than those exposed to Cd, especially in the higher Cu concentrations. These facts indicate that juveniles are more sensitive to Cu in terms of mortality, feeding and growth. Haemoglobin production was inhibited due to the scarcity of food in the experimental sediment rather than to metal exposure. Tube building was not affected by the presence of metals or by the scarcity of food. This study suggests that Cu concentrations from 50 to 150 mg L-1 and 340 mg L-1 of Cd could affect the population dynamics of this species in natural ecosystemsSe investigaron los efectos de cadmio (Cd y cobre (Cu sobre juveniles cultivados de Capitella sp. Y. Organismos juveniles de siete días de edad fueron expuestos a 13 (control, 60, 160, 240 y 340 mg Cd L-1 y a 17 (control, 50, 120 y 150 mg Cu L-1 durante 30 días. La mortalidad se incrementó significativamente al aumentar las concentraciones de Cu y, en las exposiciones a Cd, solamente fue evidente a 340 mg L-1. El tamaño corporal y la producción de heces fecales disminuyeron antes en los especímenes expuestos a Cu que en los expuestos a Cd, especialmente en las concentraciones más altas de Cu. Estos resultados indican que los juveniles son más sensibles al Cu en términos de mortalidad, alimentación y crecimiento. La producción de hemoglobina fue inhibida debido a la escasez de alimento en el sedimento experimental, más que a exposición a los metales. La formación de tubos no fue afectada por la presencia de metales ni por la escasez de alimento. Este

  10. Contenido de plomo y cadmio en aceites de girasol

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    López Martínez, M. C.

    2001-08-01

    Full Text Available We have studied the lead and cadmium content in 21 samples of sunflower oil from Andalucía (Southern Spain. These elements are toxicological importance and the sunflower oil is widely consumed in Spain. Samples were mineralized with nitric acid and vanadium pentoxide as catalyst, and ana lyzed using electrothermal atomization atomic absorption spectroscopy. The temperature-time programme for the graphite furnace was optimized for each element, and the accuracy, precision, sensitivity and detection limit of the method were evaluated. Concentrations of lead ranged from not detectable to 167.58 μg/kg and cadmium concentrations ranged from 0.87 to 8.30 μg/kg. The data obtained are not excessive and similar to those mentioned by other authors; however, one sample of the total analyzed surpassed the limit of 0.1 ppm of lead proposed by the Spanish and European Legislation. A statistical significative correlation has been established between Pb and Cd levels (p Se ha determinado el contenido de plomo y cadmio en 21 muestras de aceite de girasol, todas ellas producidas en Andalucía (Sur de España. Ambos elementos tienen una gran importancia toxicológica y el aceite de girasol es muy consumido en España. Las muestras han sido mineralizadas con ácido nítrico, utilizando pentóxido de vanadio como catalizador, y analizadas mediante espectroscopia de absorción atómica con atomización electrotérmica. Se ha optimizado el programa temperatura-tiempo del horno de grafito para cada elemento y se ha evaluado la exactitud, precisión, sensibilidad y límite de detección del método. Las concentraciones de plomo han oscilado entre no detectables y 167.58 μg/kg y las concentraciones de cadmio entre 0.87 y 8.30 μg/kg. Estos datos no resultan excesivos y concuerdan con los aportados por otros autores; no obstante, una de las muestras analizadas supera el límite máximo de 0.1 ppm de Pb establecido en las Legislaciones Española y Europea. Se

  11. Analytical Issues on the Determination of Carotenoids in Microalgae by Liquid Chromatography with Diode Array Detector; Aspectos Analiticos sobre la Determinacion de Compuestos Carotenoides en Microalgas mediante Cromatografia de Liquidos con Detector de Diodos

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    Garcia, S.; Perez, R. M.

    2012-04-11

    A preliminary study of literature review on the determination of carotenoids in microalgae samples by HPLC with diode array detector is presented. Main objective has been focused to compile data from literature and based on the main aspects of the analytical methodology used in the determination of these compounds. The work is structured as follows and affecting major analytical difficulties: Procurement and commercial availability of standard solutions. Stage of sample treatment. Chromatographic analysis. (Author) 19 refs.

  12. Microalgae Nutraceuticals

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    Marcello Nicoletti

    2016-08-01

    Full Text Available Among the new entries in the food supplements sector, an important place must be assigned to nutraceuticals containing microalgae, nowadays accounting for a large and rapidly expanding market. The marketed products are mainly based on three production strains, i.e., Spirulina and Chlorella, followed at a distance by Klamath. It is a composite situation, since two of them are cyanobacteria and the second one is eukaryotic. The reality is that each presents similarities in shape and appearance concerning the marketed form and several utilizations, and peculiarities that need special attention and adequate studies. First, general information is reported about the current scientific knowledge on each microalga, in particular the nutritional value and properties in prevention and wellbeing. Second, original studies are presented concerning the quality control of marketed products. Quality control is a key argument in nutraceuticals validation. Microalgae are particular organisms that need specific approaches to confirm identity and validate properties. The proposed control of quality is based on microscopic analysis of the morphologic characteristics. The final parts of this paper are dedicated to the need for specificity in uses and claims and to considerations about the future of microalgae in food supplements.

  13. Análisis de cadmio y cobre a nivel de ppb (parte por billón) en muestras de agua por Voltamperometría de Redisolución Anódica. Práctica simulada interactiva.

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    Milla González, Miguel; Espada Bellido, Estrella

    2014-01-01

    En este ejercicio se determina mediante Voltamperometría de Redisolución Anódica (VRA, ASV) y el Método de Adiciones Estándar (MAS, SAM) el contenido en cadmio y cobre de una muestra de agua. En principio se especifican las condiciones experimentales de la determinación y se lleva a cabo la toma de muestra ajustando el pH de la misma con reguladora acético-acetato. Se realiza la VRA primero sobre la muestra y a continuación sobre la misma muestra adicionada sucesivamente con 50 microlitros de...

  14. Dinámica del cadmio en suelos cultivados con papa en Nariño, Colombia.

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    Liliana Insuasty B

    2008-01-01

    Full Text Available Se evaluó la fijación y movilidad de cadmio en suelos dedicados al cultivo de papa en Túquerres, Pasto y Guachucal. Se tomaron muestras de suelos no disturbadas en cilindros de PVC, las cuales, luego de aplicaciones fraccionadas de cadmio con dosis de 0, 50,100 y 150 ppm, se incubaron a capacidad de campo durante cuatro meses. En estos suelos los contenidos de cadmio total e intercambiable no sobrepasaron los límites permisibles establecidos por Organización Mundial de la Salud-Organización de las Naciones Unidas para la Agricultura y la Alimentación (OMS-FAO; no obstante, la mayor cantidad del elemento se localizó en la parte superior de los núcleos, lo cual indica baja movilidad del elemento en el perfil.

  15. Contaminación de alimentos marinos por cadmio en Lima, 2015

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    Gloria Marín Vallejos

    2015-12-01

    Full Text Available Los objetivos fueron determinar las concentraciones de cadmio en ocho especies de alimentos marinos y comparar con los valores máximos permitidos según la Comisión de la Unión Europea en su Reglamento (CE Nº 1881/2006 y su modificatoria Reglamento (UE N° 488/2014. La investigación fue de carácter descriptivo, trasversal. Las muestras fueron de 100 g de cada ejemplar de pescado en tres oportunidades; los ejemplares fueron: jurel (Trachurus picturatus murphyi, langostinos (Penaeus vannamei, conchas abanico (Argopecten purpuratus, conchas blancas (Semele sp, choros (Aulacomya ater, almejas (Gari solida, machas (Mesonesma donacium y pota (Dosidicus gigas recolectadas al azar en el terminal pesquero de Villa María del Triunfo, provenientes del litoral de la región Lima, sub área 3: Chorrillos – Islas Pachacámac. El proceso de análisis se realizó por espectrofotometría de absorción atómica. Como resultados de los promedios de las concentraciones de cadmio tenemos: en pescados, jurel (Trachurus picturatus murphyi fue 0,35 mg/kg peso fresco; en crustáceos, langostino (Penaeus vannamei fue 0,42 mg/kg peso fresco; en moluscos bivalvos tenemos conchas blancas (Semele sp, conchas abanico (Argopecten purpuratus, choros (Aulacomya ater, machas (Mesonesma donacium y almejas (Gari solida fueron 0,82 – 0,83 – 1,00 – 1,28 y 1,39 mg/kg peso fresco respectivamente. Con este estudio se concluyó que las concentraciones de cadmio en pescados, en moluscos bivalvos y cefalópodos superan los límites permitidos, pero en crustáceos no superan estos límites.

  16. Contaminación de alimentos marinos por cadmio en Lima, 2015

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    Gloria Marín Vallejos

    2015-01-01

    Los objetivos fueron determinar las concentraciones de cadmio en ocho especies de alimentos marinos y comparar con los valores máximos permitidos según la Comisión de la Unión Europea en su Reglamento (CE) Nº 1881/2006 y su modificatoria Reglamento (UE) N° 488/2014. La investigación fue de carácter descriptivo, trasversal. Las muestras fueron de 100 g de cada ejemplar de pescado en tres oportunidades; los ejemplares fueron: jurel (Trachurus picturatus murphyi), langostinos (Penaeus vannamei),...

  17. Efecto del nitrógeno inorgánico (NO-3 sobre el crecimiento y la composición bioquímica de la microalga Scenedesmus sp. Cepa Laun 0001

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    Chaparro de Valencia Martha

    2004-12-01

    Full Text Available Se evaluó el efecto de seis concentraciones de nitrógeno en forma de nitrato, sobre el crecimiento y la composición bioquímica de la microalga cepa LAUN 0001 de Scenedesmus sp. (Chlorophyceae, aislada en el laboratorio de cultivo de microalgas de la Universidad Nacional de Colombia, en un
    lote de cultivos discontinuos, aireados permanentemente. Se estableció que en la razón de 3,5:1 de N:P, se obtiene el mejor rendimiento celular (18.280.000 + 2.820.000 células/ml con una tasa de crecimiento neta alta (2,9 a los siete días. La tasa de crecimiento instantánea no presentó diferencias significativas en los valores para cada tratamiento aplicado, pero se observó una tendencia general de incremento en los tratamientos con mayor concentración. La forma colonial de cuatro células por cenobio predominó en todos los tratamientos aplicados. La concentración de lípidos y carbohidratos se incrementó significativamente en los tratamientos con baja concentración
    de nitrógeno (61-77 pg/célula, mientras que en la  concentración de proteínas y clorofila no se observaron cambios significativos. La concentración de clorofila b fue levemente mayor con respecto a la clorofila a (2,65-3,42 contra 2,33-2,8 pg/célula; la concentración de carotenos fue baja en todos los tratamientos (0,62-0,76 pg/célula aumentando  significativamente en el tratamiento donde la razón de N:P es de 14:1 (1,03 pg/célula. Los valores altos registrados en los diferentes parámetros evaluados y el fácil manejo de la cepa, hacen de esta un modelo promisorio para la realización de estudios a nivel ecológico o biotecnológico.

  18. Effect of alternative mediums on production and proximate composition of the microalgae Chaetoceros muelleri as food in culture of the copepod Acartia sp. Efecto de medios alternativos sobre la producción y composición proximal de la microalga Chaetoceros muelleri como alimento en cultivo del copépodo Acartia sp.

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    Luis R Martínez-Córdova

    2012-03-01

    Full Text Available Microalgae Chaetoceros muelleri was cultured in three different mediums consisting on an agricultural fertilizer (Agr-F, aquacultural fertilizer (Aq-F and a conventional medium (F/2, control. These microalgae were later used as natural food to culture the copepod Acartia sp. The productive response and chemical proximate composition of microalgae and copepods were monitored. Growth rate and final cell concentration were higher in microalgae cultured in Agr-F compared to the control. In addition, the final biomass and cellular concentration were also the highest in Agr-F. Microalgae from Agr-F and Aq-F had higher carbohydrate and lower protein contents than those in the control. No differences in lipid and ash contents were observed. Regarding copepod production, higher densities and fecundity indexes were observed for those fed with microalgae previously cultured in Agr-F and Aq-F, compared to the control. The adult-nauplii ratio was also higher in copepods fed on microalgae from Agr-F compared to Aq-F and control. Copepods fed on Agr-F and Aq-F microalgae, had higher protein content compared to those fed on control microalgae; carbohydrates were higher in copepods fed on Agr-F as compared to Aq-F microalgae. No differences in lipid and ash contents were registered. Agr-F and Aq-F were adequate alternative mediums to produce C. muelleri, which produced higher quality microalgae that increased the copepod production.La microalga Chaetoceros muelleri fue cultivada en tres medios diferentes basados en un fertilizante agrícola (Agr-F, un fertilizante acuícola (Aq-F y un medio convencional (F/2, control. Éstas microalgas fueron posteriormente utilizadas como alimento natural para cultivar el copépodo Acartia sp. La respuesta productiva y la composición proximal de las microalgas y copépodos fueron monitoreadas. La tasa de crecimiento y concentración final de células fueron mayores en la microalga cultivada en Agr-F, comparada con el control

  19. Cuantificación de plomo, cadmio y cromo mediante sialoquímica

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    GONZÁLEZ MIREYA

    1997-01-01

    Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, p<= 0.05; gamma = -0.5224, p<= 0.05. Conclusiones. La sialoquímica juega un papel importante en la detección de contaminantes, fármacos, drogas y enfermedades locales y sistémicas. La contaminación por metales pesados sigue siendo un problema de salud pública, por lo que el gobierno debe consolidar un programa cuyo objetivo sea eliminar los diferentes contaminantes del ambiente. Asimismo, se deben realizar otros estudios para verificar la asociación de variables como sexo, edad, uso de cerámica vidriada, alimentación y zona de residencia con las concentraciones de metales pesados en saliva.

  20. Análisis de Cadmio y Plomo en aguas superficiales por potenciometría de Stripping

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    Juan Miguel Arias

    2010-12-01

    Full Text Available Se realizó la implementación y validación de una metodología analítica para determinar la presencia de cadmio y plomo en aguas supjerficiales como herramienta para la descripción del estado actual y el control cualitativo y cuantitativo de las descargas de estos metales peligrosos en los cuerpos de agua.

  1. Variabilidad estacional de cadmio en un sistema de surgencia costera del norte de Chile (Bahía Mejillones del Sur, 23° S Seasonal variability of cadmium in a coastal upwelling system off northern Chile (Mejillones bay, 23° S

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    JORGE VALDÉS

    2006-12-01

    Full Text Available Entre junio de 2002 y abril de 2003 se midió el contenido de cadmio total y disuelto entre la superficie y los 100 m de profundidad, en dos estaciones localizadas en la bahía Mejillones del Sur. El rango de cadmio total y cadmio disuelto en las aguas de esta bahía fue 0,41-10,7 y 0,08-1,61 nM, respectivamente, durante el período de muestreo. Los resultados fueron correlacionados con la estructura físico-química de la columna de agua al momento del muestreo, de manera de estudiar los patrones de variabilidad estacional de este metal en este sistema de surgencia. Las condiciones oceanográficas imperantes durante este período correspondieron a un año normal (no-El Niño. Las masas de agua presentes en la bahía correspondieron a agua subantártica, subtropical y ecuatorial subsuperficial, con diferentes grados de mezcla y estratificación durante el período de estudio. Los perfiles de cadmio presentaron una distribución vertical clásica de un micronutriente. Sin embargo estos perfiles presentaron leves diferencias que pueden ser atribuidas a la condición de mezcla de las masas de agua al interior de la bahía. Un análisis multivariado de los parámetros registrados indicó que la variación temporal de cadmio en las aguas superficiales está asociada a las fluctuaciones de la clorofila a y la temperatura. Esto sugiere que, a escala estacional, la producción de biomasa fitoplanctónica sería el principal factor que controla la distribución de cadmio en esta bahía. Por otro lado, a pesar de que el cadmio es un metal redox sensitivo no se encontró un efecto significativo de la disponibilidad de oxígeno sobre el comportamiento de este metal, de manera que la condición micróxica de las aguas de fondo de la bahía no sería un factor preponderante en el flujo de cadmio hacia los sedimentos. La razón Cd/PO4 encontrada en Mejillones es similar a la reportada en otras zonas costeras de Chile. Los bajos valores y la tendencia temporal

  2. Liquid Fuels from Microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D. A.; Sprague, S.

    1987-08-01

    The goal of the DOE/SERI Aquatic Species Program is to develop the technology to produce gasoline and diesel fuels from microalgae. Microalgae can accumulate large quantities of lipids and can thrive in high salinity water, which currently has no other use.

  3. Microalgae: biofuel production

    Directory of Open Access Journals (Sweden)

    Babita Kumari

    2013-04-01

    Full Text Available In the present day, microalgae feedstocks are gaining interest in energy scenario due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrients contents. All of these properties render them an excellent source for biofuels such as biodiesel, bioethanol and biomethane; as well as a number of other valuable pharmaceutical and nutraceutical products. The present review is a critical appraisal of the commercialization potential of microalgae biofuels. The available literature on various aspects of microalgae for e.g. its cultivation, life cycle assessment, and conceptualization of an algal biorefinery, has been done. The evaluation of available information suggests the operational and maintenance cost along with maximization of oil-rich microalgae production is the key factor for successful commercialization of microalgae-based fuels.

  4. MICROALGAE AS TOCOPHEROL PRODUCERS

    Directory of Open Access Journals (Sweden)

    V. M. Mokrosnop

    2014-04-01

    Full Text Available Microalgae are able to accumulate considerable amounts of tocopherols (up to 4 mg/g dry weight. The content of α-tocopherol to plant oils is low, whereas microalgae contain up to 97% of the tocochromanols that provides high bioactivity. The data about the content of tocopherols in eukaryotic microalgae Dunaliella tertiolecta, Nannochloropsis oculata, Isochrysis galbana, Euglena gracilis, Tetraselmis suecica, Diacronema vlkianum, as well as in the cyanobacterium Spirulina platensis are given in the paper. The largest amounts of tocopherols are synthesized by Euglena gracilis cells at mixotrophic cultivation. The level of tocopherols in microalgae depends on cultivation conditions. Two-stage biotech cultivation techniques, limiting nutrition in some biogenic elements, the introduction of exogenous carbon sources are used to increase the yield of tocopherol from microalgae. The approaches to the genetic transformation of plants leading to higher content of active vitamin E are rewieved as well.

  5. Biotechnological applications of microalgae

    OpenAIRE

    Wan-Loy Chu

    2012-01-01

    Microalgae are important biologicalresources that have a wide range of biotechnologicalapplications. Due to their high nutritional value,microalgae such as Spirulina and Chlorella are beingmass cultured for health food. A variety of high-valueproducts including polyunsaturated fatty acids (PUFA),pigments such as carotenoids and phycobiliproteins, andbioactive compounds are useful as nutraceuticals andpharmaceuticals, as well as for industrial applications. Interms of environmental biotechnolo...

  6. Microalgae: biofuel production

    OpenAIRE

    Babita Kumari; Vinay Sharma

    2013-01-01

    In the present day, microalgae feedstocks are gaining interest in energy scenario due to their fast growth potential coupled with relatively high lipid, carbohydrate and nutrients contents. All of these properties render them an excellent source for biofuels such as biodiesel, bioethanol and biomethane; as well as a number of other valuable pharmaceutical and nutraceutical products. The present review is a critical appraisal of the commercialization potential of microalgae biofuels....

  7. Bioacumulación de cadmio en ostras de la bahía de Cartagena: Bio-accumulation cadmium in oysters of Cartagena bay

    Directory of Open Access Journals (Sweden)

    Ganiveth Manjarrez Paba

    2008-07-01

    Full Text Available La Bahía de Cartagena es una de los cuerpos de agua más contaminados de la ciudad, probablemente debido a las industrias que yacen a su alrededor, algunas de las cuales vierten sus desechos en ella, con poco o ningún tipo de tratamiento. Actualmente, los metales pesados como el cadmio, las operaciones de dragado y relleno, los efluentes térmicos y la sedimentación están causando la degradación de los ecosistemas de la bahía a una tasa alarmante. Esta investigación determinó las concentraciones de cadmio en ostras capturadas en seis puntos estratégicos de la bahía: Álcalis, Bocachica, Caño de Loro, Caño Zapatero, Ciénaga Honda y Zona Franca. Los resultados revelaron que no existen diferencias estadísticamente significativas entre los valores medios de concentración de Cd en ostras en cada uno de los muestreos realizado, y que Ciénaga Honda y Bocachica fueron las estaciones donde se detectó mayor concentración del metal en ostras (25,79 mg Cd/kg y 15,11 mg Cd/kg, respectivamente. Este estudio evidencia el peligro al que están expuestos los consumidores de ostras capturadas en la Bahía de Cartagena, y permite alertar a las autoridades competentes sobre la vigilancia del control en los puntos críticos.Cartagena Bay is one of the most contaminated bodies of water in the city, probably due to the industries around it; some of them dispose of their waste in it, with little or no treatment. Currently, heavy metals such as cadmium, dredging and filling, thermal effluents and sedimentation are causing the degradation of the ecosystem of the bay at an alarming rate. This investigation found concentrations of cadmium in oysters which are caught in six strategic points of the Bay: Álcalis, Bocachica, Caño Loro, Caño Zapatero, Cienaga Honda, and the Free Zone. The results showed that there were no statistically significant differences between the mean values of Cd concentrations in oysters in each one of the samples taken, and that

  8. Niveles de plomo y cadmio en agua marina y lapas (Patella vulgata L.) de la Ría de Vigo

    OpenAIRE

    Pérez López, M.; M.C Nóvoa; J. Alonso; M. A. García Fernández; M.J. Melgar

    2003-01-01

    El empleo de seres vivos para monitorizar la contaminación por metales pesados en los ecosistemas acuáticos es de extremo interés en el campo de la ecotoxicología. En el presente estudio se han recogido muestras de agua marina y de lapas (Patella vulgata L.) de distintos puntos de la Ría de Vigo, con la intención de determinar en ellos los niveles de plomo y cadmio, por medio de una técnica de voltamperometría. Los resultados obtenidos mostraron una relación estrecha entr...

  9. Estudio de los niveles de plomo, cadmio, zinc y arsénico, en aguas de la provincia de Salamanca

    Directory of Open Access Journals (Sweden)

    Blanco Hernández Angel Luis

    1998-01-01

    Full Text Available FUNDAMENTOS: Conocer el grado de contaminación por plomo, cadmio, cinc y arsénico de las aguas de la provincia de Salamanca y su relación con la zona de procedencia de las muestras y el punto de recogida de las mismas. MÉTODO: Estudio epidemiológico transversal, observacional y descriptivo. Se han estudiado aguas procedentes de redes de abastecimiento, fuentes, manantiales, pozos, ríos, riveras y lagunas de la provincia de Salamanca, analizándose los contenidos de plomo, cadmio, zinc y arsénico de 180 muestras, mediante espectroscopía de absorción atómica. Se han comparado los niveles de contaminación por los cuatro elementos de las muestras de agua entre las cuatro unidades comarcales de la provincia. Se han comparado los niveles de contaminación por los cuatro elementos entre las aguas procedentes de redes de abastecimiento y aquellas muestras de pozos, fuentes, manantiales y aguas de superficie. RESULTADOS: Los resultados indican que un 56% de las muestras analizadas superan las concentraciones máximas admisibles de cadmio, y un 28% del total de muestras analizadas supera las concentraciones máximas admisibles de plomo, según la legislación vigente presentando niveles tolerables de zinc y arsénico. No se han observado diferencias importantes en el grado de contaminación de las aguas por los elementos estudiados entre las cuatro unidades comarcales de la provincia. No se han observado diferencias en los niveles de contaminación por los cuatro elementos entre las aguas procedentes de redes de abastecimientos y aquellas muestras de pozos, fuentes, manantiales y aguas de superficie. CONCLUSIONES: Los resultados sugieren que las aguas de la provincia de Salamanca presentan de forma "natural" altos contenidos de cadmio y plomo, probablemente debido a las características geológicas del terreno.

  10. Efecto de diferentes dietas de microalgas sobre la supervivenci y crecimiento de Apocyclops aff. panamensis (Marsh, 1913 (Copépodo: Cyclopoida cultivado bajo condiciones controladas de laboratorio - Effect of different diets from microalga on supervivenci and growth of Apocyclops aff. panamensis (Marsh, 1913 (Copépodo: Cyclopoida cultivated under controlled conditions of laboratory

    Directory of Open Access Journals (Sweden)

    Elifonso Isiordia Perez

    2006-07-01

    Full Text Available El presente trabajo fue realizado Julio 2001 con el propósito de evaluar el efecto de diferentes dietas de microalgas sobre la supervivencia y crecimiento (desarrollo de Apocyclops aff. Panamensis. El experimento duró 15 días y se realizó en las instalaciones del Instituto de Ciencias del Mar y Limnología (UNAM Unidad académica Mazatlán Sinaloa. El sistema consistió en un acuario de fibra de vidrio (50x30x40 al cual se agregó 4 litros de agua dulce filtrada 5µ se colocó un termostato para presentar condiciones controladas de temperatura (28ºC, así mismo se mantuvo constante el fotoperiodo (8 horas luz. En el interior del acuario se colocó 1 gradilla con 35 tubos de ensayo con 6 ml de agua salada a 32 ‰ filtrada con luz ultravioleta. Los copépodos fueron colectados en la boca del estero el Yugo Mazatlán, Sinaloa, transportados y aclimatados durante 15 minutos. La siembra consistió en colocar 20 nauplios en estadio II en cada tubo de ensayo. Los tratamientos que se aplicaron como alimento fueron: Chaetoceros sp. + Nannocloropsis sp. (50%:50% (T1, Isochrysis sp. + Nannocloropsis sp. (50%:50% (T2, Chaetoceros sp. + Isochrysis sp. (50%:50% (T3, Chaetoceros sp. (100% (T4, Isochrysis sp. (100% (T5, Nannocloropsis sp. (100% (T6, Chaetoceros sp. + Isochrysis sp. + Nannocloropsis sp. (1:1:1 (T7 cada uno con 5 repeticiones. La densidad de microalgas a suministrar para el presente experimento fue de 50,000 células / mililitro. Al finalizar el estudio solo los copépodos que lograron una supervivencia del 15% hasta copepodito 5 fueron los alimentados con Nanocloropsis sp. (100% y la mayor longitud (0.83 mm se presentó en copépodos alimentados con Chaetoceros sp. (100%, De acuerdo a los resultados se concluye que para lograr mayor crecimiento y supervivencia en el cultivo de copépodos Apocyclops aff. Panamensis se recomienda usar estos tratamientos como alimento. The present work was made July 2001 in order to evaluate the effect of

  11. Biotechnological exploitation of microalgae.

    Science.gov (United States)

    Gangl, Doris; Zedler, Julie A Z; Rajakumar, Priscilla D; Martinez, Erick M Ramos; Riseley, Anthony; Włodarczyk, Artur; Purton, Saul; Sakuragi, Yumiko; Howe, Christopher J; Jensen, Poul Erik; Robinson, Colin

    2015-12-01

    Microalgae are a diverse group of single-cell photosynthetic organisms that include cyanobacteria and a wide range of eukaryotic algae. A number of microalgae contain high-value compounds such as oils, colorants, and polysaccharides, which are used by the food additive, oil, and cosmetic industries, among others. They offer the potential for rapid growth under photoautotrophic conditions, and they can grow in a wide range of habitats. More recently, the development of genetic tools means that a number of species can be transformed and hence used as cell factories for the production of high-value chemicals or recombinant proteins. In this article, we review exploitation use of microalgae with a special emphasis on genetic engineering approaches to develop cell factories, and the use of synthetic ecology approaches to maximize productivity. We discuss the success stories in these areas, the hurdles that need to be overcome, and the potential for expanding the industry in general. PMID:26400987

  12. Carotenoids in Microalgae.

    Science.gov (United States)

    Henríquez, Vitalia; Escobar, Carolina; Galarza, Janeth; Gimpel, Javier

    2016-01-01

    Carotenoids are a class of isoprenoids synthesized by all photosynthetic organisms as well as by some non-photosynthetic bacteria and fungi with broad applications in food, feed and cosmetics, and also in the nutraceutical and pharmaceutical industries. Microalgae represent an important source of high-value products, which include carotenoids, among others. Carotenoids play key roles in light harvesting and energy transfer during photosynthesis and in the protection of the photosynthetic apparatus against photooxidative damage. Carotenoids are generally divided into carotenes and xanthophyls, but accumulation in microalgae can also be classified as primary (essential for survival) and secondary (by exposure to specific stimuli).In this chapter, we outline the high value carotenoids produced by commercially important microalgae, their production pathways, the improved production rates that can be achieved by genetic engineering as well as their biotechnological applications. PMID:27485224

  13. Production of biodiesel from microalgae

    Directory of Open Access Journals (Sweden)

    Danilović Bojana R.

    2014-01-01

    Full Text Available In recent years, more attention has been paid to the use of third generation feedstocs for the production of biodiesel. One of the most promising sources of oil for biodiesel production are microalgae. They are unicellular or colonial photosynthetic organisms, with permanently increasing industrial application in the production of not only chemicals and nutritional supplements but also biodiesel. Biodiesel productivity per hectare of cultivation area can be up to 100 times higher for microalgae than for oil crops. Also, microalgae can grow in a variety of environments that are often unsuitable for agricultural purposes. Microalgae oil content varies in different species and can reach up to 77% of dry biomass, while the oil productivity by the phototrophic cultivation of microalgae is up to 122 mg/l/d. Variations of the growth conditions and the implementation of the genetic engineering can induce the changes in the composition and productivity of microalgal oil. Biodiesel from microalgae can be produced in two ways: by transesterification of oil extracted from biomass or by direct transesterification of algal biomass (so called in situ transesterification. This paper reviews the curent status of microalgae used for the production of biodiesel including their isolation, cultivation, harvesting and conversion to biodiesel. Because of high oil productivity, microalgae will play a significant role in future biodiesel production. The advantages of using microalgae as a source for biofuel production are increased efficiency and reduced cost of production. Also, microalgae do not require a lot of space for growing and do not have a negative impact on the global food and water supplies. Disadvantages of using microalgae are more difficult separation of biomass and the need for further research to develop standardized methods for microalgae cultivation and biodiesel production. Currently, microalgae are not yet sustainable option for the commercial

  14. Functional ingredients from microalgae

    NARCIS (Netherlands)

    Buono, S.; Langellotti, A.L.; Martello, A.; Rinna, F.; Fogliano, V.

    2014-01-01

    A wide variety of natural sources are under investigation to evaluate their possible use for new functional ingredient formulation. Some records attested the traditional and ancient use of wild harvested microalgae as human food but their cultivation for different purposes started about 40 years ago

  15. Biotechnological applications of microalgae

    Directory of Open Access Journals (Sweden)

    Wan-Loy Chu

    2012-07-01

    Full Text Available Microalgae are important biologicalresources that have a wide range of biotechnologicalapplications. Due to their high nutritional value,microalgae such as Spirulina and Chlorella are beingmass cultured for health food. A variety of high-valueproducts including polyunsaturated fatty acids (PUFA,pigments such as carotenoids and phycobiliproteins, andbioactive compounds are useful as nutraceuticals andpharmaceuticals, as well as for industrial applications. Interms of environmental biotechnology, microalgae areuseful for bioremediation of agro-industrial wastewater,and as a biological tool for assessment and monitoring ofenvironmental toxicants such as heavy metals, pesticidesand pharmaceuticals. In recent years, microalgae haveattracted much interest due to their potential use asfeedstock for biodiesel production. In Malaysia, therehas been active research on microalgal biotechnologyfor the past 30 years, tapping into the potential of ourrich microalgal resources for high-value products andapplications in wastewater treatment and assessmentof environmental toxicants. A culture collection ofmicroalgae has been established, and this serves asan important resource for microalgal biotechnologyresearch. Microalgal biotechnology should continue tobe regarded as a priority area of research in this country.

  16. Biofuels from Microalgae

    NARCIS (Netherlands)

    Barbosa, M.J.; Wijffels, R.H.

    2013-01-01

    Microalgae are a promising feedstock for sustaineble production of biofuela due to their unique capacity to reach high lipid productivities. Although the promises are there, production costs and energy requirements are high and the technology is still ammature for the production of bulk products. It

  17. Food commodities from microalgae

    NARCIS (Netherlands)

    Draaisma, R.B.; Wijffels, R.H.; Slegers, P.M.; Brentner, L.B.; Roy, A.; Barbosa, M.J.

    2013-01-01

    The prospect of sustainable production of food ingredients from photoautotrophic microalgae was reviewed. Clearly, there is scope for microalgal oils to replace functions of major vegetable oils, and in addition to deliver health benefits to food products. Furthermore, with a limited production surf

  18. Biohydrogen from Microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Dubini, Alexandra; Gonzalez-Ballester, David

    2016-03-01

    This chapter provides an overview of the current state of knowledge of the mechanisms involved in biohydrogen production from microalgae. The known limitations linked to photohydrogen productivity are addressed. Particular attention is given to physiological and molecular strategies to sustain and improve hydrogen production. The impact of different nutrient stresses and the effect of carbon supply on hydrogen production are discussed. The genetic and metabolic engineering approaches for increasing hydrogen production are outlined.

  19. Fuels from microalgae

    Energy Technology Data Exchange (ETDEWEB)

    1989-06-01

    Many species of aquatic plants can provide a source of renewable energy. Some species of microalgae, in particular, produce lipids -- oils that can be extracted and converted to a diesel fuel substitute or to gasoline. Since 1979 the Aquatic Species Program element of the Biofuels Program, has supported fundamental and applied research to develop the technology for using this renewable energy resource. This document, produced by the Solar Technical Information Program, provides an overview of the DOE/SERI Aquatic Species Program element. Chapter 1 is an introduction to the program and to the microalgae. Chapter 2 is an overview of the general principles involved in making fuels from microalgae. It also outlines the technical challenges to producing economic, high-energy transportation fuels. Chapter 3 provides an overview of the Algal Production and Economic Model (APEM). This model was developed by researchers within the program to identify aspects of the process critical to performance with the greatest potential to reduce costs. The analysis using this model has helped direct research sponsored by the program. Finally, Chapter 4 provides an overview of the Aquatic Species Program and describes current research. 28 refs., 17 figs.

  20. Phototrophic pigment production with microalgae

    NARCIS (Netherlands)

    Mulders, K.J.M.

    2014-01-01

    Abstract

    Microalgal pigments are regarded as natural alternatives for food colorants. To facilitate optimization of microalgae-based pigment production, this thesis aimed to obtain key insights in the pigment metabolism of phototrophic microalgae, with the main  focus

  1. Harvesting of microalgae by bio-flocculation

    OpenAIRE

    Salim, S.; Bosma, R.; Vermuë, M.H.; Wijffels, R.H.

    2011-01-01

    The high-energy input for harvesting biomass makes current commercial microalgal biodiesel production economically unfeasible. A novel harvesting method is presented as a cost and energy efficient alternative: the bio-flocculation by using one flocculating microalga to concentrate the non-flocculating microalga of interest. Three flocculating microalgae, tested for harvesting of microalgae from different habitats, improved the sedimentation rate of the accompanying microalga and increased the...

  2. Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

    OpenAIRE

    CARLOS E. RIQUELME; RUBÉN E. AVENDAÑO-HERRERA

    2003-01-01

    El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y f...

  3. Management of oxidative stress by microalgae.

    Science.gov (United States)

    Cirulis, Judith T; Scott, J Ashley; Ross, Gregory M

    2013-01-01

    The aim of this review is to provide an overview of the current research on oxidative stress in eukaryotic microalgae and the antioxidant compounds microalgae utilize to control oxidative stress. With the potential to exploit microalgae for the large-scale production of antioxidants, interest in how microalgae manage oxidative stress is growing. Microalgae can experience increased levels of oxidative stress and toxicity as a result of environmental conditions, metals, and chemicals. The defence mechanisms for microalgae include antioxidant enzymes such as superoxide dismutase, catalase, peroxidases, and glutathione reductase, as well as non-enzymatic antioxidant molecules such as phytochelatins, pigments, polysaccharides, and polyphenols. Discussed herein are the 3 areas the literature has focused on, including how conditions stress microalgae and how microalgae respond to oxidative stress by managing reactive oxygen species. The third area is how beneficial microalgae antioxidants are when administered to cancerous mammalian cells or to rodents experiencing oxidative stress.

  4. Fuel from microalgae lipid products

    Energy Technology Data Exchange (ETDEWEB)

    Hill, A.M.; Feinberg, D.A.

    1984-04-01

    The large-scale production of microalgae is a promising method of producing a renewable feedstock for a wide variety of fuel products currently refined from crude petroleum. These microalgae-derived products include lipid extraction products (triglycerides, fatty acids, and hydrocarbons) and catalytic conversion products (paraffins and olefins). Microalgal biomass productivity and lipid composition of current experimental systems are estimated at 66.0 metric tons per hectare year and 30% lipid content. Similar yields in a large-scale facility indicate that production costs are approximately six times higher than the average domestic price for crude, well-head petroleum. Based on achievable targets for productivity and production costs, the potential for microalgae as a fuel feedstock is presented in context with selected process refining routes and is compared with conventional and alternative feedstocks (e.g., oilseeds) with which microalgae must compete. 24 references, 9 figures, 4 tables.

  5. Microalgae biofuel potentials (review).

    Science.gov (United States)

    Ghasemi, Y; Rasoul-Amini, S; Naseri, A T; Montazeri-Najafabady, N; Mobasher, M A; Dabbagh, F

    2012-01-01

    With the decrease of fossil based fuels and the environmental impact of them over the planet, it seems necessary to seek the sustainable sources of clean energy. Biofuels, is becoming a worldwide leader in the development of renewable energy resources. It is worthwhile to say that algal biofuel production is thought to help stabilize the concentration of carbon dioxide in the atmosphere and decrease global warming impacts. Also, among algal fuels' attractive characteristics, algal biodiesel is non toxic, with no sulfur, highly biodegradable and relatively harmless to the environment if spilled. Algae are capable of producing in excess of 30 times more oil per acre than corn and soybean crops. Currently, algal biofuel production has not been commercialized due to high costs associated with production, harvesting and oil extraction but the technology is progressing. Extensive research was conducted to determine the utilization of microalgae as an energy source and make algae oil production commercially viable. PMID:22586908

  6. Bioadsorción de Cadmio (II en Solución Acuosa por Biomasas Fúngicas Biosorption of Cadmium (II in Aqueous Solutions by Fungal Biomass

    Directory of Open Access Journals (Sweden)

    Ismael Acosta

    2007-01-01

    Full Text Available Se determinó la bioadsorción de Cadmio (II en solución por la biomasa celular de quince hongos, por el método colorimétrico de la ditizona. La biomasa de Mucor rouxii IM-80 fue más eficiente en la remoción de Cadmio (II en solución (8.2 mg/g seguida de M. rouxii mutante (7.1 mg/g, A. flavus I (5.9 mg/g y Helminthosporium sp (5.4 mg/g. Para la biomasa de M. rouxii-IM-80, la mayor bioadsorción fue a pH= 5.0-6.0, a 28ºC durante 40 horas con 1.0 mg/200 mL de concentración inicial de Cadmio (II y 80 mg/200 mL de biomasa celular. Se concluye que algunas biomasas fúngicas remueven eficientemente Cadmio (II en solución y pueden utilizarse para descontaminar nichos acuáticos contaminados con este metalThe biosorption of dissolved Cadmium (II using cellular biomass of 15 fungi, using a dithizone colorimetric method, was determined. The Mucor rouxii IM-80 biomass was more efficient in removing Cadmium (II from solution (8.2 mg/g, followed by the M. rouxii mutant (7.1 mg/g, Aspergillus flavus I (5.9 mg/g and Helminthosporium sp (5.4 mg/g biomasses. The highest biosorption for M. rouxii IM-80 was at pH 5.0-6.0, at 28ºC for 40 h employing 1.0 mg/200mL of Cadmium (II as initial concentration, and 80 mg/200 mL of fungal biomass. It was concluded that some fungal biomass efficiently removed Cadmium (II from solution and could be used for decontamination of aquatic habitats polluted with this metal

  7. Valoración del residuo de rapa de uva como bioadsorbente para la eliminación de cadmio de efluentes acuosos

    OpenAIRE

    Moreno Rabasco, Mª Carmen

    2005-01-01

    Los metales pesados son sustancias tóxicas capaces de causar graves daños en los organismos vivos. Una de las principales propiedades de los metales pesados es que no son biodegradables y permanecen durante mucho tiempo en el entorno, circulando y acumulándose en el medio y los seres vivos, por lo que es necesario evitar su incorporación al entorno a través de vertidos contaminados. De entre los distintos metales tóxicos, el cadmio es uno de los más peligrosos. La contaminac...

  8. Estudio comparativo de la toxicidad del metilmercurio, cadmio (II) y cromo (VI) en cultivos primarios de neuronas y astrocitos de rata

    OpenAIRE

    V Uroz Martínez; MJ Anadón-Baselga; M. Capó-Martí

    2008-01-01

    El presente estudio pretende comparar la concentración letal 50 (CL , dosis que causa la muerte del 50% de las células) de 50 metilmercurio, cadmio (II) y cromo (VI) en cultivos primarios de corteza de rata. Se emplearon hemisferios cerebrales de rata para preparar los cultivos primarios. Los cultivos primarios de neuronas fueron realizados a partir de ratas Wistar de 14-16 días de gestación, usando el medio Eagle modificado por Dulbecco. Para los cultivos primarios de as...

  9. LÍMITES PERMISIBLES DE ACUMULACIÓN DE CADMIO, NÍQUEL Y PLOMO EN SUELOS DEL VALLE DEL MEZQUITAL, HIDALGO

    OpenAIRE

    Antonio Vázquez-Alarcón; Lenom J. Cajuste; Rogelio Carrillo-González; Benjamín Zamudio-González; Edna Álvarez-Sánchez; Javier Z. Castellanos-Ramos

    2005-01-01

    En México, se carece de información relativa a la calidad de suelos en términos del contenido de metales pesados. Los datos disponibles corresponden a información generada en otros países, extrapolada a los suelos nacionales. Con el presente estudio se trata de realizar una aproximación a los valores de referencia de acumulación de cadmio, níquel y plomo en suelos. La metodología consistió en resolver un modelo que relaciona el límite permisible de acumulación con variables como dosis de inge...

  10. Contenidos de Cadmio, Cobre, Zinc y Plomo en órganos de Rhizophora mangle de la Ciénaga Grande de Santa Marta, Caribe colombiano.

    OpenAIRE

    Naranjo-Sánchez, Y.A.; Troncoso-Olivo, W.

    2008-01-01

    Para determinar los contenidos de cadmio, cobre, zinc y plomo en hojas, tallos y raíces de Rhizophora mangle se tomaron muestras en tres parcelas ubicadas en la desembocadura del río Sevilla-Ciénaga Grande de Santa Marta, en octubre de 2003. Las mediciones de las concentraciones de metales, se hicieron mediante la técnica de espectrometría de emisión atómica de plasma inductivamente acoplado (ICP-AES). Los resultados indicaron que la concentración de plomo en órganos de R. mangle estuvo bajo ...

  11. Biorefinery of microalgae for food and fuel

    NARCIS (Netherlands)

    Vanthoor-Koopmans, M.; Wijffels, R.H.; Barbosa, M.J.; Eppink, M.H.M.

    2013-01-01

    Microalgae are a promising source for proteins, lipids and carbohydrates for the food/feed and biofuel industry. In comparison with soya and palm oil, microalgae can be grown in a more efficient and sustainable way. To make microalgae production economically feasible it is necessary to optimally use

  12. Heavy metal sorption by microalgae

    International Nuclear Information System (INIS)

    Viable microalgae are known to be able to accumulate heavy metals (bioaccumulation). Against a background of the increasing environmental risks caused by heavy metals, the microalgae Chlorella vulgaris and Spirulina platensis and their potential for the biological removal of heavy metals from aqueous solutions were taken as an example for investigation. Small-scale cultivation tests (50 l) with Cd-resistant cells of Chlorella vulgaris have shown that approx. 40% of the added 10 mg Cd/l was removed from the solution within seven days. At this heavy metal concentration sensitive cells died. Non-viable microalgae are able to eliminate heavy metal ions in a short time by biosorption in uncomplicated systems, without any toxicity problems. Compared with original biomasses, the sorption capacity of microalgal by-products changes only insignificantly. Their low price makes them economical. (orig.)

  13. Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos

    Directory of Open Access Journals (Sweden)

    Subero Neudis

    2011-06-01

    Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años,las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelosagrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil delsuelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinarla capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferenciastexturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinóel tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd;la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y secompararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemáticode Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cdpor los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayorcapacidad de adsorción.

  14. Airborne Microalgae: Insights, Opportunities, and Challenges.

    Science.gov (United States)

    Tesson, Sylvie V M; Skjøth, Carsten Ambelas; Šantl-Temkiv, Tina; Löndahl, Jakob

    2016-04-01

    Airborne 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. PMID:26801574

  15. Circadian rhythms in microalgae production

    NARCIS (Netherlands)

    Winter, de L.

    2015-01-01

    Abstract Thesis: Circadian rhythms in microalgae production Lenneke de Winter The sun imposes a daily cycle of light and dark on nearly all organisms. The circadian clock evolved to help organisms program their activities at an appropriate time during this daily cycle. For example,

  16. Cell disruption for microalgae biorefineries

    NARCIS (Netherlands)

    Günerken, E.; Hondt, d' E.; Eppink, M.H.M.; Garcia-Gonzalez, L.; Elst, K.; Wijffels, R.H.

    2015-01-01

    Microalgae are a potential source for various valuable chemicals for commercial applications ranging from nutraceuticals to fuels. Objective in a biorefinery is to utilize biomass ingredients efficiently similarly to petroleum refineries in which oil is fractionated in fuels and a variety of product

  17. Current Status and Prospects of Biodiesel Production from Microalgae

    Directory of Open Access Journals (Sweden)

    Yuhuan Liu

    2012-07-01

    Full Text Available Microalgae represent a sustainable energy source because of their high biomass productivity and ability to remove air and water born pollutants. This paper reviews the current status of production and conversion of microalgae, including the advantages of microalgae biodiesel, high density cultivation of microalgae, high-lipid content microalgae selection and metabolic control, and innovative harvesting and processing technologies. The key barriers to commercial production of microalgae biodiesel and future perspective of the technologies are also discussed.

  18. Current Status and Prospects of Biodiesel Production from Microalgae

    OpenAIRE

    Yuhuan Liu; Rongsheng Ruan; Zhenyi Du; Xiaodan Wu

    2012-01-01

    Microalgae represent a sustainable energy source because of their high biomass productivity and ability to remove air and water born pollutants. This paper reviews the current status of production and conversion of microalgae, including the advantages of microalgae biodiesel, high density cultivation of microalgae, high-lipid content microalgae selection and metabolic control, and innovative harvesting and processing technologies. The key barriers to commercial production of microalgae biodie...

  19. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Gonzalez Conde, E.; Garcia-Balboa, C.

    2014-07-01

    Although bioaccumulation is an enzymatic process that requires live microalgae bio sorption is based on physicochemical interactions, and it is not necessary that microalgae are alive, whereby dried microalgae biomass achieves the same results. This alternative could represent a new safe and inexpensive way to recover U. (Author)

  20. Microalgae for Bioenergy; Key Technology Nodes

    OpenAIRE

    Ywetta Maleterova; Frantisek Kastanek; Milena Rouskova; Martina Matejkova; Petr Kastanek; Olga Solcova

    2015-01-01

    Microalgae have increasingly gained research interest as a source of lipids for biodiesel production. The wet way processing of harvested microalgae was suggested and evaluated with respect to the possible environmental impacts and production costs. This study is focused on the three key steps of the suggested process: flocculation, water recycling, and extraction of lipids. Microalgae strains with high content of lipids were chosen for cultivation and subsequent treatment process. Ammonium h...

  1. Alternative Binder from microalgae : Algoroute project

    OpenAIRE

    CHAILLEUX, Emmanuel; AUDO, Mariane; Bujoli, Bruno; Queffelec, Clémence; LEGRAND, Jack; LEPINE, Olivier

    2012-01-01

    Renewable energy sources are developed worldwide because of high oil prices and to limit greenhouse gas emissions. In this context some groups have focused their work on vegetable oils and particularly on microalgae. The last decade has seen an increased scientific interest in the extraction of lipids from microalgae for the production of biodiesel. Microalgae present many advantages compared to other energy crops including a high growth rate, a high biomass production, and noncompetititon wi...

  2. Morphology of photoreceptor systems in microalgae.

    Science.gov (United States)

    Gualtieri, P

    2001-06-01

    The polyphyletic artificial assemblage of O(2)-evolving, photosynthetic organisms, collectively referred to as algae, include a highly diverse array of organisms from large seaweeds (macroalgae) to unicellular microalgae. Phycology, the study of algae, focuses on morphological, ecological, physiological and molecular biological aspects of these organisms. Most microalgae show a photo-behaviour, i.e. they sense light and move towards it; in this review we will describe morphological similarities and differences in the photoreceptive system of microalgae.

  3. Microalgae Culture Collection: 1984-1985

    Energy Technology Data Exchange (ETDEWEB)

    1984-09-01

    The Microalgae Culture Collection at the Solar Energy Research Institute has been established for the maintenance and distribution of strains that have been characterized for biomass fuel applications.

  4. Production of biofuels obtained from microalgae

    OpenAIRE

    Luis Carlos Fernández-Linares; Jorge Montiel Montoya; Aarón Millán Oropeza; Jesús Agustín Badillo Corona

    2012-01-01

    A review of the situation of bio-fuels in the world, mainly of biodiesel is made. A comparison among the different raw materials for the synthesis of biodiesel is done and it is emphasized in the production of biodiesel from microalgae. The different fresh and salt water micro-algae in its lipid content and productivity are compared. A review of the process of biosynthesis of lipids in microalgae and how to improve the production of lipids in microalgae is shown. It is discussed the importanc...

  5. Microalgae as Sources of Carotenoids

    Directory of Open Access Journals (Sweden)

    Francisco Xavier Malcata

    2011-04-01

    Full Text Available Marine microalgae constitute a natural source of a variety of drugs for pharmaceutical, food and cosmetic applications—which encompass carotenoids, among others. A growing body of experimental evidence has confirmed that these compounds can play important roles in prevention (and even treatment of human diseases and health conditions, e.g., cancer, cardiovascular problems, atherosclerosis, rheumatoid arthritis, muscular dystrophy, cataracts and some neurological disorders. The underlying features that may account for such favorable biological activities are their intrinsic antioxidant, anti-inflammatory and antitumoral features. In this invited review, the most important issues regarding synthesis of carotenoids by microalgae are described and discussed—from both physiological and processing points of view. Current gaps of knowledge, as well as technological opportunities in the near future relating to this growing field of interest, are also put forward in a critical manner.

  6. Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos

    Directory of Open Access Journals (Sweden)

    Nereida Sánchez

    2011-04-01

    Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años, las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelos agrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil del suelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinar la capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferencias texturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinó el tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd; la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y se compararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemático de Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cd por los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayor capacidad de adsorción.

  7. Production of Biodiesel from Microalgae

    OpenAIRE

    Danilović Bojana R.; Avramović Jelena M.; Ćirić Jovan T.; Savić Dragiša S.; Veljković Vlada B.

    2012-01-01

    In recent years, more attention has been paid to the use of third generation feedstocs for the production of biodiesel. One of the most promising sources of oil for biodiesel production are microalgae. They are unicellular or colonial photosynthetic organisms, with permanently increasing industrial application in the production of not only chemicals and nutritional supplements but also biodiesel. Biodiesel productivity per hectare of cultivation area can be...

  8. Third generation biofuels from microalgae

    OpenAIRE

    Dragone, Giuliano; Fernandes, Bruno Daniel; A.A. Vicente; Teixeira, J. A.

    2010-01-01

    Biofuel production from renewable sources is widely considered to be one of the most sustainable alternatives to petroleum sourced fuels and a viable means for environmental and economic sustainability. Microalgae are currently being promoted as an ideal third generation biofuel feedstock because of their rapid growth rate, CO2 fixation ability and high production capacity of lipids; they also do not compete with food or feed crops, and can be produced on non-arable land. Microalg...

  9. Closing Domestic Nutrient Cycles Using Microalgae

    NARCIS (Netherlands)

    Vasconcelos Fernandes, T.; Shresthat, R.; Suit, Y.; Papini, G.; Zeeman, G.; Vet, L.E.M.; Wijffels, R.H.; Lamers, P.P.

    2015-01-01

    This study demonstrates that microalgae can effectively recover all P and N from anaerobically treated black water (toilet wastewater). Thus, enabling the removal of nutrients from the black water and the generation of a valuable algae product in one step. Screening experiments with green microalgae

  10. Production of biofuels obtained from microalgae

    Directory of Open Access Journals (Sweden)

    Luis Carlos Fernández-Linares

    2012-09-01

    Full Text Available A review of the situation of bio-fuels in the world, mainly of biodiesel is made. A comparison among the different raw materials for the synthesis of biodiesel is done and it is emphasized in the production of biodiesel from microalgae. The different fresh and salt water micro-algae in its lipid content and productivity are compared. A review of the process of biosynthesis of lipids in microalgae and how to improve the production of lipids in microalgae is shown. It is discussed the importance of the genetic manipulation to highly lipid-producing microalgae (example: Botryrococuus braunni, Nannochloropsis sp, Noechlorisoleobundans and Nitschia sp.. A study of the advantages and disadvantages of the different systems of cultivation of microalgae is also made. Finally, it is shown a perspective of biofuels from microalgae. Among the main challenges to overcome to produce biodiesel from microalgae are: the cost of production of biomass, which involves the optimization of media, selection and manipulation of strains and photobioreactors design. The processof separation of biomass, the extraction of oils and by-products, the optimization of the process of transesterification, purification and use of by-products must also be considered.

  11. Microalgae production in a biofilm photobioreactor

    NARCIS (Netherlands)

    Blanken, Ward

    2016-01-01

    Microalgae can be used to produce high-value compounds, such as pigments or high value fatty acids, or as a feedstock for lower value products such as food and feed compounds, biochemicals, and biofuels. In order to produce these bulk products competitively, it is required to lower microalgae produc

  12. Application of photobioreactors to cultivation of microalgae

    Institute of Scientific and Technical Information of China (English)

    陈雷; 王光玉

    2003-01-01

    An overview of photobioreactors now in use for production of microalgae world wide is presented, andthe application of photobioreactors to the cultivation of microalgae is discussed in detail. It is pointed out thathigh cell density and industrial production of microalgae can be achieved using many kinds of closed photobiore-actors including fermentor, tubular and flat plate photobioreactors, and the cultivation of Spirulina, Chlorella,Dunaliella tertiolecta and Porphyridium cruentrim by photobioreactors can achieve higher and steadier produc-tivity than the cultivation of microalgae by an open air system. More and more researches indicate that tubularand flat plate photobioreactors are the development trend for photobioreactors with bubbles and air lift stirrers,and high bright light-emitting diodes are the most economic light source with great potential for future develop-ment of photobioreactors. Photobioreactors can also be used for the production of high-value metabolite ( EPA orDHA) using some microalgae species for energy development and environment protection.

  13. Cuantificación de plomo, cadmio y cromo mediante sialoquímica Quantification of lead, cadmium and chromium through sialochemistry

    Directory of Open Access Journals (Sweden)

    MIREYA GONZÁLEZ

    1997-05-01

    Full Text Available Objetivo. Determinar las concentraciones de plomo, cadmio y cromo, y establecer su posible asociación con diferentes factores sociodemográficos. Material y métodos. Se seleccionó una muestra representativa de 100 estudiantes de posgrado de la Facultad de Odontología de la Universidad Nacional Autónoma de México (UNAM, a los cuales se les colectó saliva total no estimulada. Dichas muestras fueron analizadas por espectrofotometría de absorción atómica con horno de grafito. Resultados. Metales pesados como el plomo, el cadmio y el cromo se encuentran en concentraciones mucho más altas que las informadas en la literatura: Pb, = 3.10 m g/dL-1, máxima: 16.8 my g/dL-1, y mínima: 0.04 my g/dL-1; Cd, = 0.25 my g/dL-1, máxima: 2.04 my g/dL-1, y mínima: 0.004 my g/dL-1; y Cr, = 1.43 my g/dL-1, máxima: 4.82 my g/dL-1, y mínima: 0.05 my g/dL-1. Asimismo, variables como la zona de residencia, el sexo, la edad y la ingesta de comida enlatada no influyen en los niveles de plomo y cromo. Sin embargo, en el caso del cadmio y la edad existe una asociación inversa (ji²= 5.9012, pObjective. To determine the concentration of lead (Pb, cadmium (Cd, and chromium (Cr and establish the possible association of these heavy metals with some sociodemographic factors. Material and methods. A representative sample of one hundred dental students from the National Autonomous University of Mexico living in Mexico City participated in this study. Unstimulated human whole saliva samples were analyzed by Atomic Absorption Spectroscopy. Results. Concentrations of Pb, Cd, and Cr were higher than those reported elsewhere: Pb ( or = 3.10 m g/dL-1; Maximum: 16.8 mu g/dL-1 and Minimum: 0.04 mu g/dL-1, Cd ( or = 0.25 mu g/dL-1; Maximum: 2.04 mu g/dL-1 and Minimum: 0.004 mu g/dL-1 and Cr ( or = 1.43 mu g/dL-1; Maximum: 4.82 mu g/dL-1 and Minimum: 0.05 mu g/dL-1. No association was found between the variables studied (age, sex, geographic area and canned food consumption

  14. Interacción bacteria-microalga en el ambiente marino y uso potencial en acuicultura Microalgae and bacteria interaction in the aquatic environment and their potential use in aquaculture

    Directory of Open Access Journals (Sweden)

    CARLOS E. RIQUELME

    2003-12-01

    Full Text Available El presente estudio tiene como objetivo revisar el conocimiento generado sobre el rol que juegan las interacciones bacteria-microalga en ambientes marinos y dulceacuícolas, definiendo las posibles aplicaciones que puede tener el conocimiento de estas interacciones en el manejo de las aguas costeras y sistemas acuícolas. Los antecedentes proporcionados en este análisis permiten sugerir que bacterias y/o microalgas, constituyen una alternativa para el control de proliferaciones de bacterias y fitoplancton causantes de efectos dañinos en ambientes naturales y sistemas cerrados de cultivo. Además, las interacciones específicas entre bacteria-microalga permitiría la optimización de sistemas productivos en la industria acuícola. Sin embargo, los mecanismos de estas interacciones son pobremente entendidos. Futuras investigaciones debieran ser dirigidas a comprender el modo de acción de las interacciones bacteria-microalga a nivel molecularThe objective of this survey is to review the knowledge generated with respect to the role of bacteria-microalgae interaction play in marine and fresh environments, and to define the possible application of these microorganisms on the management of costal water and aquaculture systems. This review proposes that bacteria and/or microalgae are an alternative to control the proliferation of bacteria and phytoplankton that cause damages in natural environments or in closed culture systems. Also, the knowledge of specific interactions between bacteria and microalgae will allow the optimization of productive systems in aquaculture. However, until date the mechanisms involved in these interactions are poorly understood. Therefore, future investigations should be directed towards understanding the mode of action of such interactions at a molecular level

  15. Microalgae as Solar-Powered Protein Factories.

    Science.gov (United States)

    Hempel, Franziska; Maier, Uwe G

    2016-01-01

    Microalgae have an enormous ecological relevance as they contribute significantly to global carbon fixation. But also for biotechnology microalgae became increasingly interesting during the last decades as many algae provide valuable natural products. Especially the high lipid content of some species currently attracts much attention in the biodiesel industry. A further application that emerged some years ago is the use of microalgae as expression platform for recombinant proteins. Several projects on the production of therapeutics, vaccines and feed supplements demonstrated the great potential of using microalgae as novel low-cost expression platform. This review provides an overview on the prospects and advantages of microalgal protein expression systems and gives an outlook on potential future applications. PMID:27165330

  16. Biofuels. Microalgae, back to square research

    International Nuclear Information System (INIS)

    Microalgae represent a huge potential for the production of some molecules which can be transformed in fuels, polymers, or lipids, with a per-hectare yield much higher than conventional crops like palm oil. But this exploitation of microalgae revealed to be still too expensive. Further researches are therefore needed. They concern the choice of microalgae strains, and techniques of extraction of targeted molecules. As far as strains and molecule production are concerned, the CEA's bacteria and microalgae bio-genetics and bio-technologies laboratory (LB3M) tries to identify genes responsible of productivity, and a production unit is being built in Libourne. As far as extraction techniques are concerned, the Seche Environnement company is supporting a project to develop humid techniques, and the LB3M uses metabolic and genetic engineering to produce hydrocarbon. Other academic research laboratories and projects are indicated (in Israel, Netherlands, San Diego, Melbourne, and Almeria)

  17. Feasibility of remote sensing benthic microalgae

    Science.gov (United States)

    Zingmark, R. G.

    1979-01-01

    Results of data analyses from multispectral scanning data are presented. The data was collected in July 1977 for concentration of chlorophyll in benthic microalgae (mainly diatoms) on an estuary mudflat.

  18. Modeling and visual simulation of Microalgae photobioreactor

    Science.gov (United States)

    Zhao, Ming; Hou, Dapeng; Hu, Dawei

    Microalgae is a kind of nutritious and high photosynthetic efficiency autotrophic plant, which is widely distributed in the land and the sea. It can be extensively used in medicine, food, aerospace, biotechnology, environmental protection and other fields. Photobioreactor which is important equipment is mainly used to cultivate massive and high-density microalgae. In this paper, based on the mathematical model of microalgae which grew under different light intensity, three-dimensional visualization model was built and implemented in 3ds max, Virtools and some other three dimensional software. Microalgae is photosynthetic organism, it can efficiently produce oxygen and absorb carbon dioxide. The goal of the visual simulation is to display its change and impacting on oxygen and carbon dioxide intuitively. In this paper, different temperatures and light intensities were selected to control the photobioreactor, and dynamic change of microalgal biomass, Oxygen and carbon dioxide was observed with the aim of providing visualization support for microalgal and photobioreactor research.

  19. Screening of antioxidant activity in microalgae

    Directory of Open Access Journals (Sweden)

    Mariana F.G. Assunção

    2014-06-01

    Both sets of results indicate an interesting antioxidant potential in microalgae belonging to the groups Eustigmatophyceae and Chlorophyceae. Tested species of these groups showed ABTS•+ values comparable to grape and raspberry ethanolic extracts, confirmed also by the DPPH• method.

  20. Biologically Active Metabolites Synthesized by Microalgae

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2015-01-01

    Full Text Available 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.

  1. Global Evaluation of Biofuel Potential from Microalgae

    OpenAIRE

    Moody, Jeffrey W.

    2014-01-01

    Traditional terrestrial crops are currently being utilized as a feedstock for biofuels but resource requirements and low yields limit the sustainability and scalability. Comparatively, next generation feedstocks, such as microalgae, have inherent advantages such as higher solar energy efficiencies, larger lipid fractions, utilization of waste carbon dioxide, and cultivation on poor quality land. The assessment of microalgae-based biofuel production systems through lifecycle, technoeconomic, a...

  2. Efficiency of the biodiesel production from microalgae

    Science.gov (United States)

    Chernova, N. I.; Kiseleva, S. V.; Popel', O. S.

    2014-06-01

    Biomass of the highly productive algae is a promising nontraditional raw material for biopower engineering, including production of energy and motor fuels from it. The paper presents an analysis of the efficiency of solar energy conversion to microalgae biofuel based both on the general theoretical approaches and on the experimental results obtained in various pilot projects. Some data on the economic efficiency of biofuel production from algae are also discussed. The possible ways to enhance the efficiency of microalgae energy use are formulated.

  3. Harvesting microalgae grown on wastewater.

    Science.gov (United States)

    Udom, Innocent; Zaribaf, Behnaz H; Halfhide, Trina; Gillie, Benjamin; Dalrymple, Omatoyo; Zhang, Qiong; Ergas, Sarina J

    2013-07-01

    The costs and life cycle impacts of microalgae harvesting for biofuel production were investigated. Algae were grown in semi-continuous culture in pilot-scale photobioreactors under natural light with anaerobic digester centrate as the feed source. Algae suspensions were collected and the optimal coagulant dosages for metal salts (alum, ferric chloride), cationic polymer (Zetag 8819), anionic polymer (E-38) and natural coagulants (Moringa Oleifera and Opuntia ficus-indica cactus) were determined using jar tests. The relative dewaterability of the algae cake was estimated by centrifugation. Alum, ferric chloride and cationic polymer could all achieve >91% algae recovery at optimal dosages. Life cycle assessment (LCA) and cost analysis results revealed that cationic polymer had the lowest cost but the highest environmental impacts, while ferric chloride had the highest cost and lowest environmental impacts. Based on the LCA results, belt presses are the recommended algae dewatering technology prior to oil extraction. PMID:23648758

  4. Harvesting microalgae grown on wastewater.

    Science.gov (United States)

    Udom, Innocent; Zaribaf, Behnaz H; Halfhide, Trina; Gillie, Benjamin; Dalrymple, Omatoyo; Zhang, Qiong; Ergas, Sarina J

    2013-07-01

    The costs and life cycle impacts of microalgae harvesting for biofuel production were investigated. Algae were grown in semi-continuous culture in pilot-scale photobioreactors under natural light with anaerobic digester centrate as the feed source. Algae suspensions were collected and the optimal coagulant dosages for metal salts (alum, ferric chloride), cationic polymer (Zetag 8819), anionic polymer (E-38) and natural coagulants (Moringa Oleifera and Opuntia ficus-indica cactus) were determined using jar tests. The relative dewaterability of the algae cake was estimated by centrifugation. Alum, ferric chloride and cationic polymer could all achieve >91% algae recovery at optimal dosages. Life cycle assessment (LCA) and cost analysis results revealed that cationic polymer had the lowest cost but the highest environmental impacts, while ferric chloride had the highest cost and lowest environmental impacts. Based on the LCA results, belt presses are the recommended algae dewatering technology prior to oil extraction.

  5. Bioremediation of wastewater using microalgae

    Science.gov (United States)

    Chalivendra, Saikumar

    Population expansion and industrial development has deteriorated the quality of freshwater reservoirs around the world and has caused freshwater shortages in certain areas. Discharge of industrial effluents containing toxic heavy metals such as Cd and Cr into the environment have serious impact on human, animal and aquatic life. In order to solve these problems, the present study was focused on evaluating and demonstrating potential of microalgae for bioremediation of wastewater laden with nitrogen (N) in the form of nitrates, phosphorous (P) in the form of phosphates, chromium (Cr (VI)) and cadmium (Cd (II)). After screening several microalgae, Chlorella vulgaris and algae taken from Pleasant Hill Lake were chosen as candidate species for this study. The viability of the process was demonstrated in laboratory bioreactors and various experimental parameters such as contact time, initial metal concentration, algae concentration, pH and temperature that would affect remediation rates were studied. Based on the experimental results, correlations were developed to enable customizing and designing a commercial Algae based Wastewater Treatment System (AWTS). A commercial AWTS system that can be easily customized and is suitable for integration into existing wastewater treatment facilities was developed, and capital cost estimates for system including installation and annual operating costs were determined. The work concludes that algal bioremediation is a viable alternate technology for treating wastewater in an economical and sustainable way when compared to conventional treatment processes. The annual wastewater treatment cost to remove N,P is ~26x lower and to remove Cr, Cd is 7x lower than conventional treatment processes. The cost benefit analysis performed shows that if this technology is implemented at industrial complexes, Air Force freight and other Department of Defense installations with wastewater treatment plants, it could lead to millions of dollars in

  6. 3D-Microalgae software used for the estimation of microalgae biovolumes and surface area

    Directory of Open Access Journals (Sweden)

    Anton M. Lyakh

    2012-03-01

    Full Text Available The main steps of using of an original software package 3D-Microalgae for constructing three-dimensional geometric models of microalgae shells and estimating of their biovolume and surface areas are described. An improved method realized in the software allows significantly increasing the accuracy of that morphometrical characteristics calculation

  7. The Potential for Microalgae as Bioreactors to Produce Pharmaceuticals

    Science.gov (United States)

    Yan, Na; Fan, Chengming; Chen, Yuhong; Hu, Zanmin

    2016-01-01

    As photosynthetic organisms, microalgae can efficiently convert solar energy into biomass. Microalgae are currently used as an important source of valuable natural biologically active molecules, such as carotenoids, chlorophyll, long-chain polyunsaturated fatty acids, phycobiliproteins, carotenoids and enzymes. Significant advances have been achieved in microalgae biotechnology over the last decade, and the use of microalgae as bioreactors for expressing recombinant proteins is receiving increased interest. Compared with the bioreactor systems that are currently in use, microalgae may be an attractive alternative for the production of pharmaceuticals, recombinant proteins and other valuable products. Products synthesized via the genetic engineering of microalgae include vaccines, antibodies, enzymes, blood-clotting factors, immune regulators, growth factors, hormones, and other valuable products, such as the anticancer agent Taxol. In this paper, we briefly compare the currently used bioreactor systems, summarize the progress in genetic engineering of microalgae, and discuss the potential for microalgae as bioreactors to produce pharmaceuticals. PMID:27322258

  8. The Potential for Microalgae as Bioreactors to Produce Pharmaceuticals.

    Science.gov (United States)

    Yan, Na; Fan, Chengming; Chen, Yuhong; Hu, Zanmin

    2016-01-01

    As photosynthetic organisms, microalgae can efficiently convert solar energy into biomass. Microalgae are currently used as an important source of valuable natural biologically active molecules, such as carotenoids, chlorophyll, long-chain polyunsaturated fatty acids, phycobiliproteins, carotenoids and enzymes. Significant advances have been achieved in microalgae biotechnology over the last decade, and the use of microalgae as bioreactors for expressing recombinant proteins is receiving increased interest. Compared with the bioreactor systems that are currently in use, microalgae may be an attractive alternative for the production of pharmaceuticals, recombinant proteins and other valuable products. Products synthesized via the genetic engineering of microalgae include vaccines, antibodies, enzymes, blood-clotting factors, immune regulators, growth factors, hormones, and other valuable products, such as the anticancer agent Taxol. In this paper, we briefly compare the currently used bioreactor systems, summarize the progress in genetic engineering of microalgae, and discuss the potential for microalgae as bioreactors to produce pharmaceuticals. PMID:27322258

  9. Temporal trending of lead and cadmium contamination in the Vigo estuary intertidal area Evolución temporal de la contaminación por plomo y cadmio en la zona intermareal de la ría de Vigo

    Directory of Open Access Journals (Sweden)

    J. Alonso Díaz

    2004-12-01

    Full Text Available At the present work, limpet (Patella vulgata L. and seaweed (Ulva lactuca specimens have been monthly sampled at the same point from the Vigo estuary, during a year. Heavy metal (cadmium and lead content has been determined by means of differential pulse anodic stripping voltammetry in both limpet and seaweed tissues, as well as in seawater. The obtained results have shown the main heavy metal content in limpet soft tissues with respect to shell, with maximum concentrations of 3 ppm (limpet shell for lead, whereas the highest content for cadmium was identified in seaweed samples (1.1 ppm. The statistical study revealed the existence of a clear correlation between cadmium and lead concentrations in seaweed samples.En el presente trabajo se han recogido muestras de lapa (Patella vulgata L. y alga verde (Ulva lactuca en un mismo punto de muestreo de la ría de Vigo, con una periodicidad mensual, a lo largo de un año, analizándose por medio de voltamperometría de redisolución anódica la concentración en dos metales pesados con claras repercusiones toxicológicas, cadmio y plomo, en estas muestras, así como en el agua marina. Los resultados obtenidos mostraron la mayor concentración de ambos metales en los tejidos blandos de las lapas frente a las valvas de estos moluscos, con valores máximos en el caso del plomo próximos a 3 ppm (valva de lapa, mientras que para el cadmio se situó en torno a 1,1 ppm (alga verde. El estudio estadístico permitió poner en evidencia una clara correlación estadística entre los valores de cadmio y plomo cuantificados en las muestras de algas.

  10. The Potential for Microalgae as Bioreactors to Produce Pharmaceuticals

    OpenAIRE

    Na Yan; Chengming Fan; Yuhong Chen; Zanmin Hu

    2016-01-01

    As photosynthetic organisms, microalgae can efficiently convert solar energy into biomass. Microalgae are currently used as an important source of valuable natural biologically active molecules, such as carotenoids, chlorophyll, long-chain polyunsaturated fatty acids, phycobiliproteins, carotenoids and enzymes. Significant advances have been achieved in microalgae biotechnology over the last decade, and the use of microalgae as bioreactors for expressing recombinant proteins is receiving incr...

  11. Efficient recovery of uranium using genetically improved microalgae

    International Nuclear Information System (INIS)

    Although bioaccumulation is an enzymatic process that requires live microalgae bio sorption is based on physicochemical interactions, and it is not necessary that microalgae are alive, whereby dried microalgae biomass achieves the same results. This alternative could represent a new safe and inexpensive way to recover U. (Author)

  12. Harvesting microalgae by bio-flocculation and autoflocculation

    NARCIS (Netherlands)

    Salim, S.

    2013-01-01

    Harvesting in commercial microalgae production plants is generally done by centrifugation, but this requires upto about 50% of the total energy gained from the microalgae. The energy needed for harvesting can be reduced considerably by pre-concentration of the microalgae prior to further dewatering.

  13. Microalgae bulk growth model with application to industrial scale systems

    NARCIS (Netherlands)

    Quinn, J.; Winter, de L.; Bradley, T.

    2011-01-01

    The scalability of microalgae growth systems is a primary research topic in anticipation of the commercialization of microalgae-based biofuels. To date, there is little published data on the productivity of microalgae in growth systems that are scalable to commercially viable footprints. To inform t

  14. Microalgae for bioenergy: key technology nodes.

    Science.gov (United States)

    Maleterova, Ywetta; Kastanek, Frantisek; Rouskova, Milena; Matejkova, Martina; Kastanek, Petr; Solcova, Olga

    2015-01-01

    Microalgae have increasingly gained research interest as a source of lipids for biodiesel production. The wet way processing of harvested microalgae was suggested and evaluated with respect to the possible environmental impacts and production costs. This study is focused on the three key steps of the suggested process: flocculation, water recycling, and extraction of lipids. Microalgae strains with high content of lipids were chosen for cultivation and subsequent treatment process. Ammonium hydroxide was tested as the flocculation agent and its efficiency was compared with chitosan. Determined optimal flocculation conditions for ammonium hydroxide enable the water recycling for the recurring microalgae growth, which was verified for the use of 30, 50, and 80% recycled water. For extraction of the wet microalgae hexane, hexane/ethanol and comparative chloroform/methanol systems were applied. The efficiency of hexane/ethanol extraction system was found as comparable with chloroform/methanol system and it seems to be promising owing to its low volatility and toxicity and mainly the low cost. PMID:26000336

  15. Microalgae for Bioenergy: Key Technology Nodes

    Directory of Open Access Journals (Sweden)

    Ywetta Maleterova

    2015-01-01

    Full Text Available Microalgae have increasingly gained research interest as a source of lipids for biodiesel production. The wet way processing of harvested microalgae was suggested and evaluated with respect to the possible environmental impacts and production costs. This study is focused on the three key steps of the suggested process: flocculation, water recycling, and extraction of lipids. Microalgae strains with high content of lipids were chosen for cultivation and subsequent treatment process. Ammonium hydroxide was tested as the flocculation agent and its efficiency was compared with chitosan. Determined optimal flocculation conditions for ammonium hydroxide enable the water recycling for the recurring microalgae growth, which was verified for the use of 30, 50, and 80% recycled water. For extraction of the wet microalgae hexane, hexane/ethanol and comparative chloroform/methanol systems were applied. The efficiency of hexane/ethanol extraction system was found as comparable with chloroform/methanol system and it seems to be promising owing to its low volatility and toxicity and mainly the low cost.

  16. An Overview of Biocement Production from Microalgae

    Directory of Open Access Journals (Sweden)

    Dessy Ariyanti

    2011-12-01

    Full Text Available The invention of microorganism’s involvement in carbonate precipitation, has lead the exploration of this process in the field of construction engineering. Biocement is a product innovation from developing bioprocess technology called biocementation. Biocement refers to CaCO3 deposit that formed due to microorganism activity in the system rich of calcium ion. The primary role of microorganism in carbonate precipitation is mainly due to their ability to create an alkaline environment (high pH and DIC increase through their various physiological activities. Three main groups of microorganism that can induce the carbonate precipitation: (i photosynthetic microorganism such as cyanobacteria and microalgae; (ii sulphate reducing bacteria; and (iii some species of microorganism involved in nitrogen cycle. Microalgae are photosynthetic microorganism and utilize urea using urease or urea amidolyase enzyme, based on that it is possible to use microalgae as media to produce biocement through biocementation. This paper overviews biocement in general, biocementation, type of microorganism and their pathways in inducing carbonate precipitation and the prospect of microalgae to be used in biocement production.  Keywords— Biocement, Biocementation, Microalgae, CaCO3 precipitation

  17. Availability and Utilization of Pigments from Microalgae.

    Science.gov (United States)

    Begum, Hasina; Yusoff, Fatimah Md; Banerjee, Sanjoy; Khatoon, Helena; Shariff, Mohamed

    2016-10-01

    Microalgae are the major photosynthesizers on earth and produce important pigments that include chlorophyll a, b and c, β-carotene, astaxanthin, xanthophylls, and phycobiliproteins. Presently, synthetic colorants are used in food, cosmetic, nutraceutical, and pharmaceutical industries. However, due to problems associated with the harmful effects of synthetic colorants, exploitation of microalgal pigments as a source of natural colors becomes an attractive option. There are various factors such as nutrient availability, salinity, pH, temperature, light wavelength, and light intensity that affect pigment production in microalgae. This paper reviews the availability and characteristics of microalgal pigments, factors affecting pigment production, and the application of pigments produced from microalgae. The potential of microalgal pigments as a source of natural colors is enormous as an alternative to synthetic coloring agents, which has limited applications due to regulatory practice for health reasons. PMID:25674822

  18. Global evaluation of biofuel potential from microalgae.

    Science.gov (United States)

    Moody, Jeffrey W; McGinty, Christopher M; Quinn, Jason C

    2014-06-10

    In the current literature, the life cycle, technoeconomic, and resource assessments of microalgae-based biofuel production systems have relied on growth models extrapolated from laboratory-scale data, leading to a large uncertainty in results. This type of simplistic growth modeling overestimates productivity potential and fails to incorporate biological effects, geographical location, or cultivation architecture. This study uses a large-scale, validated, outdoor photobioreactor microalgae growth model based on 21 reactor- and species-specific inputs to model the growth of Nannochloropsis. This model accurately accounts for biological effects such as nutrient uptake, respiration, and temperature and uses hourly historical meteorological data to determine the current global productivity potential. Global maps of the current near-term microalgae lipid and biomass productivity were generated based on the results of annual simulations at 4,388 global locations. Maximum annual average lipid yields between 24 and 27 m(3)·ha(-1)·y(-1), corresponding to biomass yields of 13 to 15 g·m(-2)·d(-1), are possible in Australia, Brazil, Colombia, Egypt, Ethiopia, India, Kenya, and Saudi Arabia. The microalgae lipid productivity results of this study were integrated with geography-specific fuel consumption and land availability data to perform a scalability assessment. Results highlight the promising potential of microalgae-based biofuels compared with traditional terrestrial feedstocks. When water, nutrients, and CO2 are not limiting, many regions can potentially meet significant fractions of their transportation fuel requirements through microalgae production, without land resource restriction. Discussion focuses on sensitivity of monthly variability in lipid production compared with annual average yields, effects of temperature on productivity, and a comparison of results with previous published modeling assumptions.

  19. Electricity generation and microalgae cultivation in microbial fuel cell using microalgae-enriched anode and bio-cathode

    International Nuclear Information System (INIS)

    Highlights: • Electricity generation and microalgae cultivation was done simultaneously. • Microalgae biomass was used as a substrate at anode. • Freshwater microalgae were grown at cathode. • The maximum power output of 1926 ± 21.4 mW/m2 was achieved. • Microalgae produced biomass up to 1247 ± 52 mg/L. - Abstract: In this study, a microbial fuel cell (MFC) was developed to treat waste, produce electricity and to grow microalgae simultaneously. Dead microalgae biomass (a potential pollution vector in streams) was used as a substrate at anode. CO2 generated at anode was used to grow freshwater microalgae at cathode. The performance of microalgae-fed MFC was compared with acetate-fed MFC. The maximum power density of 1926 ± 21.4 mW/m2 (8.67 ± 0.10 W/m3, at Rext = 100 Ω) and Coulombic efficiency (CE) of 6.3 ± 0.2% were obtained at 2500 mg COD/L of microalgae powder (0.5 g/L). Microalgae captured CO2 (5–14%, v/v) to produce a biomass concentration of 1247 ± 52 mg/L. However, microalgae could not grow in acetate-fed (0.5 g/L) MFC (acetate-control) and without anodic CO2 supplying MFC (CO2-control)

  20. Towards high productivities of microalgae in photobioreactors

    NARCIS (Netherlands)

    Bosma, R.

    2010-01-01

    The biodiversity of microalgae is enormous and they represent an almost untapped source of unique algae products. Presently, there is a niche market for high-value algal products (e.g. carotenoids and fatty acids). To make commercial production of low-value bulk products possible, still many bottlen

  1. Fatty Acid Content of Indonesian Aquatic Microalgae

    Directory of Open Access Journals (Sweden)

    TRI PRARTONO

    2010-12-01

    Full Text Available High utilization of fossil fuel increases the level of carbon dioxide in the atmosphere and results in global warming phenomenon. These things establish the world’s thought to look for the other alternative energy that can reduce the use of fossil fuel even to be replaced by the substitute. Recently, Indonesia has been doing the research of microalgae as a feedstock of an alternative biofuel. Fatty acid content that microalgae have is also high to produce biofuel. The steps used in this research is a 7 days cultivation, harvesting, extraction using hexane, and fatty acid identification using Gas Chromatography of microalgae species. Fatty acid component in some species such as Chlorella sp., Scenedesmus sp., Nannochloropsis sp., and Isochrysis sp. is between 0.21-29.5%; 0.11-25.16%; 0.30-42.32%; 2.06-37.63%, respectively, based on dry weight calculation. The high content of fatty acid in some species of microalgae showed the potential to be the feedstock of producing biofuel in overcoming the limited utilization from petroleum (fossil fuel presently.

  2. Hydrothermal Liquefaction of the Microalgae Phaeodactylum tricornutum

    DEFF Research Database (Denmark)

    Sigaard Christensen, Per; Peng, Gaël; Vogel, Frédéric;

    2014-01-01

    The microalgae Phaeodactylum tricornutum was processed by hydrothermal liquefaction in order to assess the influence of reaction temperature and reaction time on the product and elemental distribution. The experiments were carried out at different reaction times (5 and 15 min) and over a wide range...

  3. Microalgae growth on concentrated human urine

    NARCIS (Netherlands)

    Tuantet, K.; Janssen, M.G.J.; Temmink, H.; Zeeman, G.; Wijffels, R.H.; Buisman, C.J.N.

    2014-01-01

    In this study, for the first time, a microalga was grown on non-diluted human urine. The essential growth requirements for the species Chlorella sorokiniana were determined for different types of human urine (fresh, hydrolysed, male and female). Batch experimental results using microtiter plates sho

  4. Negative effects of Phaeocystis globosa on microalgae

    NARCIS (Netherlands)

    Liu Jiesheng, [No Value; Van Rijssel, Marion; Yang Weidong, [No Value; Peng Xichun, [No Value; Lue Songhui, [No Value; Wang Yan, [No Value; Chen Jufang, [No Value; Wang Zhaohui, [No Value; Qi Yuzao, [No Value

    2010-01-01

    The potential allelopathic effects of the microalga, Phaeocystis globosa Scherffel, on three harmful bloom algae, Prorocentrum donghaiense Lu, Chattonella marina (Subrahmanyan) Hara et Chihara and Chattonella ovata Hara et Chihara were studied. The growth of C. marina and C. ovata was markedly reduc

  5. Harvesting of microalgae by bio-flocculation

    NARCIS (Netherlands)

    Salim, S.; Bosma, R.; Vermuë, M.H.; Wijffels, R.H.

    2011-01-01

    The high-energy input for harvesting biomass makes current commercial microalgal biodiesel production economically unfeasible. A novel harvesting method is presented as a cost and energy efficient alternative: the bio-flocculation by using one flocculating microalga to concentrate the non-flocculati

  6. Microalgae harvesting and processing: a literature review

    Energy Technology Data Exchange (ETDEWEB)

    Shelef, G.; Sukenik, A.; Green, M.

    1984-08-01

    The objective of this report is to present a discussion of the literature review performed on methods of harvesting microalgae. There is no single best method of harvesting microalgae. The choice of preferable harvesting technology depends on algae species, growth medium, algae production, end product, and production cost benefit. Algae size is an important factor since low-cost filtration procedures are presently applicable only for harvesting fairly large microalgae. Small microalgae should be flocculated into larger bodies that can be harvested by one of the methods mentioned above. However, the cells' mobility affects the flocculation process, and addition of nonresidual oxidants to stop the mobility should be considered to aid flocculation. The decision between sedimentation or flotation methods depends on the density difference between the algae cell and the growth medium. For oil-laden algae with low cell density, flotation technologies should be considered. Moreover, oxygen release from algae cells and oxygen supersaturation conditions in growth medium support the use of flotation methods. If high-quality algae are to be produced for human consumption, continuous harvesting by solid ejecting or nozzle-type disc centrifuges is recommended. These centrifuges can easily be cleaned and sterilized. They are suitable for all types of microalgae, but their high operating costs should be compared with the benefits from their use. Another basic criterion for selecting the suitable harvesting procedure is the final algae paste concentration required for the next process. Solids requirements up to 30% can be attained by established dewatering processes. For more concentrated solids, drying methods are required. The various systems for algae drying differ both in the extent of capital investment and the energy requirements. Selection of the drying method depends on the scale of operation and the use for which the dried product is intended.

  7. Microalgae as a safe food source for animals: nutritional characteristics of the acidophilic microalga Coccomyxa onubensis

    Directory of Open Access Journals (Sweden)

    Francisco Navarro

    2016-10-01

    Full Text Available Background: Edible microalgae are marine or fresh water mesophilic species. Although the harvesting of microalgae offers an abundance of opportunities to the food and pharmaceutical industries, the possibility to use extremophilic microalgae as a food source for animals is not well-documented. Objective: We studied the effects of dietary supplementation of a powdered form of the acidophilic microalga Coccomyxa onubensis on growth and health parameters of laboratory rats. Method: Four randomly organized groups of rats (n=6 were fed a standard diet (Diet 1, control or with a diet in which 0.4% (Diet 2, 1.25% (Diet 3, or 6.25% (Diet 4 (w/w of the standard diet weight was substituted with dried microalgae powder, respectively. The four groups of animals were provided ad libitum access to feed for 45 days. Results: C. onubensis biomass is rich in protein (44.60% of dry weight and dietary fiber (15.73%, and has a moderate carbohydrate content (24.8% and a low lipid content (5.4% in which polyunsaturated fatty acids represent 65% of the total fatty acid. Nucleic acids are present at 4.8%. No significant difference was found in growth rates or feed efficiency ratios of the four groups of rats. Histological studies of liver and kidney tissue revealed healthy organs in control and C. onubensis-fed animals, while plasma hematological and biochemical parameters were within healthy ranges for all animals. Furthermore, animals fed a microalgae-enriched diet exhibited a statistically significant decrease in both blood cholesterol and triglyceride levels. The blood triglyceride content and very low density lipoprotein-cholesterol levels decreased by about 50% in rats fed Diet 4. Conclusions: These data suggest that C. onubensis may be useful as a food supplement for laboratory animals and may also serve as a nutraceutical in functional foods. In addition, microalgae powder-supplemented diets exerted a significant hypocholesterolemic and hypotriglyceridemic

  8. Catalytic deoxygenation of microalgae oil to green hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chen; Bruck, Thomas; Lercher, Johannes A.

    2013-05-14

    Microalgae are high potential raw biomass material for triglyceride feedstock, due to their high oil content and rapid growth rate, and because algae cultivation does not compete with edible food on arable land. This review addresses first the microalgae cultivation with an overview of the productivity and growth of microalgae, the recovery of lipids from the microalgae, and chemical compositions of microalgae biomass and microalgal oil. Second, three basic approaches are discussed to downstream processing for the production of green gasoline and diesel hydrocarbons from microalgae oil, including cracking with zeolite, hydrotreating with supported sulfided catalysts and hydrodeoxygenation with non-sulfide metal catalysts. For the triglyceride derived bio-fuels, only “drop-in” gasoline and diesel range components are discussed in this review.

  9. Adsorción de Cadmio en Solución utilizando como Adsorbente Material Tobáceo Modificado Adsorption of Cadmium in Solution using a Modified Tuffaceous Material as Adsorbent

    Directory of Open Access Journals (Sweden)

    Monica L Rueda

    2010-01-01

    Full Text Available Se estudia la adsorción de iones de cadmio en solución por un mineral tobáceo, procedente de la Provincia de Neuquén, Argentina, utilizado en forma natural y luego de concentrado en fracción arcilla. El análisis químico fue efectuado por Plasma Acoplado Inductivamente y la composición mineralógica fue identificada por Difracción de Rayos X. La isoterma de adsorción fue obtenida usando cadmio en solución en el rango de concentración de 100 a 1000 ppm. El ensayo experimental se llevó a cabo con una relación sólido/liquido de 2 % p/v y tiempo de contacto de 24 horas. La retención de cadmio se determinó por diferencia entre la concentración inicial y la concentración luego del contacto con el sólido, lectura efectuada por espectrometría de absorción atómica. La mayor proporción de fracción arcillosa (esmectita e illita lograda por la purificación, permitió reducir el contenido de cuarzo y feldespato y aumentar la capacidad de adsorción de 15.75 a 22.86 mg·g-1.The adsorption of Cd ions from solution by a tuffaceous material (in natural and after clay concentration from Neuquén Province, Argentine was tested. The solid was used as collected and after being concentrated in the clay fraction. The chemical analysis was performed by Plasma Couple Inductively and the mineralogical composition was identified by X-ray diffraction. The adsorption isotherms were carried out by using concentrations of Cd solutions in the range of 100 to 1000 ppm. The solid/liquid ratio was 2 % w/v and the contact time was 24 hours. The amount of metal ion retained was obtained by difference between the initial concentration and supernatant concentration after contacting metal ions solution with the solid. The metal concentrations were determined by atomic absorption spectrometry. The main mineralogical components of the sample were smectite/illite (clay minerals, quartz and feldspar. The purification of the tuffaceous material in clay minerals

  10. Combustion of Microalgae Oil and Ethanol Blended with Diesel Fuel

    OpenAIRE

    Saddam H. Al-lwayzy; Talal Yusaf

    2015-01-01

    Using renewable oxygenated fuels such as ethanol is a proposed method to reduce diesel engine emission. Ethanol has lower density, viscosity, cetane number and calorific value than petroleum diesel (PD). Microalgae oil is renewable, environmentally friendly and has the potential to replace PD. In this paper, microalgae oil (10%) and ethanol (10%) have been mixed and added to (80%) diesel fuel as a renewable source of oxygenated fuel. The mixture of microalgae oil, ethanol and petroleum diesel...

  11. Microalgae downstream processing and economical approaches of biodiesel producton processes

    OpenAIRE

    Ríos, Sergio Daniel

    2013-01-01

    Microalgae oil has been identified as a reliable resource for biodiesel production due to its high lipid productivity and potential cultivation in non-fertile locations. However, high scale production of microalgae based biodiesel depends on the optimization of the entire process to be economically feasible. The present work combine the optimization of microalgae downstream processes with computational tools for the modeling of different scenarios of the harvesting, oil extraction and transes...

  12. The potential of insects and microalgae in a biobased economy

    OpenAIRE

    Vogels, Liesbeth; Vleugels, Rut; Vreysen, Steven; Van Miert, Sabine; Rombouts, Lieve; Doumen, Joris; Verbinnen, Bert; Van Der Borght, Mik; Van Daele, Guy

    2014-01-01

    In our modern society there is a great need for the production of food, feed and raw materials from alternative sources of biomass. In the search for answers to the future food challenges and for sustainable production of raw materials, insects and microalgae offer excellent opportunities. Thomas More provides, in cooperation with KU Leuven, multidisciplinary research on the growth and use of insects and microalgae for various applications. Both insects and microalgae possess numerous of i...

  13. Effect of microalga Spirulina platensis (Arthrospira platensis on hippocampus lipoperoxidation and lipid profile in rats with induced hypercholesterolemia

    Directory of Open Access Journals (Sweden)

    Telma Elita Bertolin

    2009-10-01

    Full Text Available Studies have been conducted on microalga Spirulina platensis (Arthrospira platensis due to its therapeutic potential in several areas, including the capacity for preventing and decreasing the damages caused by hyperlipidemia and the antioxidant activity. The aim of the study was to evaluate the effect of microalga Spirulina platensis on hippocampus lipoperoxidation and lipid profile in rats with induced hypercholesterolemia during 60 days. The measurement of hippocampus lipoperoxidation did not demonstrate significant difference (p>0.05 when Spirulina platensis was added to hypercholesterolemic diet. The evaluation of lipid profile showed that the administration of the microalga in therapeutic and preventive ways led to a significant protective effect (pA microalga Spirulina platensis (Arthrospira platensis vem sendo fonte de pesquisas devido a evidências de seu potencial terapêutico em diversas áreas, dentre elas a capacidade de prevenção e diminuição dos danos causados por dislipidemias e sua atividade antioxidante. Objetivou-se avaliar o efeito da microalga Spirulina platensis sobre a lipoperoxidação no hipocampo e perfil lipídico sérico em ratos com hipercolesterolemia induzida durante 60 dias. A dosagem da lipoperoxidação no hipocampo não demonstrou diferença significativa (p>0,05 quando Spirulina platensis foi adicionada na dieta hipercolêsterolemica. A avaliação do perfil lipídico demonstrou que a administração da microlaga de forma terapêutica e preventiva demonstrou efeito significativo (p<0,05 na proteção do desenvolvimento de hipercolesterolemia.

  14. Lipid extraction from microalgae using a single ionic liquid

    Science.gov (United States)

    Salvo, Roberto Di; Reich, Alton; Dykes, Jr., H. Waite H.; Teixeira, Rodrigo

    2013-05-28

    A one-step process for the lysis of microalgae cell walls and separation of the cellular lipids for use in biofuel production by utilizing a hydrophilic ionic liquid, 1-butyl-3-methylimidazolium. The hydrophilic ionic liquid both lyses the microalgae cell walls and forms two immiscible layers, one of which consists of the lipid contents of the lysed cells. After mixture of the hydrophilic ionic liquid with a suspension of microalgae cells, gravity causes a hydrophobic lipid phase to move to a top phase where it is removed from the mixture and purified. The hydrophilic ionic liquid is recycled to lyse new microalgae suspensions.

  15. Review on biofuel oil and gas production processes from microalgae

    International Nuclear Information System (INIS)

    Microalgae, as biomass, are a potential source of renewable energy, and they can be converted into energy such as biofuel oil and gas. This paper presents a brief review on the main conversion processes of microalgae becoming energy. Since microalgae have high water content, not all biomass energy conversion processes can be applied. By using thermochemical processes, oil and gas can be produced, and by using biochemical processes, ethanol and biodiesel can be produced. The properties of the microalgae product are almost similar to those of offish and vegetable oils, and therefore, it can be considered as a substitute of fossil oil.

  16. Removal of freshwater microalgae by a magnetic separation method

    Science.gov (United States)

    Vergini, Sofia S.; Aravantinou, Andriana F.; Manariotis, Ioannis D.

    2013-04-01

    Some species of microalgae, with high growth rate and high lipid content, appear to be attractive alternatives as a feedstock for biodiesel production. The high-energy input for harvesting biomass and removing the water from the algae makes current commercial microalgal biodiesel production cost expensive. The major techniques currently employed in microalgae harvesting and recovery include centrifugation, coagulation-flocculation, bio-flocculation, filtration and screening, gravity sedimentation, and flotation. The purpose of this study was to investigate the harvesting of microalgae cells by coagulation using magnetic activated carbon, magnetite (FeO4) nanoparticles, and common chemical coagulants. Scenedesmus rubescens was selected and cultivated in 10 L flasks under continuous artificial light. Samples were taken at different operation intervals. Jar tests were conducted to investigate the effect of adsorption of microalgae on the magnetic material. The removal efficiency of microalgae was affected by the coagulants dose, stirring time and speed, and the initial microalgae concentration. The recovery of microalgae was greater in cultures with high initial microalgae concentration compared to cultures with low microalgae concentrations.

  17. Learning sustainability by developing a solar dryer for microalgae retrieval

    Directory of Open Access Journals (Sweden)

    Benedita Malheiro

    2016-01-01

    Full Text Available Excessive fossil fuel consumption is driving the search for alternative energy production solutions and, in particular, for sustainable sources of energy such as microalgae, from which biodiesel, among other useful compounds, can be obtained. After producing the microalgae, they must be harvested and dried. Existing drying solutions consume too much energy and are, therefore, expensive and unsustainable. The goal of this EPS@ISEP Spring 2013 project was to develop a solar microalgae dryer for the microalgae laboratory of ISEP. A multinational team of five students from distinct fields of study was responsible for designing and building the solar microalgae dryer prototype. The prototype includes a control system to ensure that the microalgae are not destroyed during the drying process. The solar microalgae dryer works as a distiller, extracting the excess water from the microalgae suspension. This paper details the design steps, the building technologies, the ethical and sustainable concerns and compares the prototype with existing solutions. The proposed sustainable microalgae drying process is competitive as far as energy usage is concerned. Finally, the project contributed to increase the team’s sustainable development awareness, active learning and motivation.

  18. Microalgae - Energy Production and Wastewater Purification : Three Scenarios for Microalgae Cultivation in the Kujala Waste Management Center

    OpenAIRE

    Järvelin, Pekka

    2011-01-01

    The diminishing fossil fuels and the emission problems are increasing the effort to develop more sustainable and carbon-neutral energy resources. Microalgae are a promising resource of renewable energy such as biodiesel and biogas. Compared to the current biofuel production from food crops, microalgae grow fast, do not require arable land and can be cultivated in nutrient rich waste waters. The biofuel productivity of microalgae per hectare per year is many times higher than with other biofue...

  19. Accumulation of zirconium by microalgae and cyanobacteria

    International Nuclear Information System (INIS)

    The accumulation of zirconium (Zr) as [Zr4-(OH)8(H2O)16]8+ by cyanobacteria and microalgae has been characterized. In all the cyanobacterial and microalgal species examined, accumulation consisted of a single rapid energy-independent phase (''biosorp-tion'') and no energy-dependent accumulation was observed. Biosorption of Zr was concentration-dependent, followed a Freundlich adsorption isotherm, and was dependent on pH, showing decreased accumulation with decreased pH. Prior treatment with Na+, K+, Cs+, Ca2+, Mg2+ and Sr2+ (added as chlorides) also decreased Zr accumulation by cyanobacteria and microalgae, probably a result of competition between Zr ions and othecations, including H+, for available binding sites on the cell walls. Zr desorption from micoalgae and cyanobacteria was increased by increasing external cation concentrations or by decreasing the pH of the desorption agent. (orig.)

  20. Engineering challenges in biodiesel production from microalgae.

    Science.gov (United States)

    Aguirre, Ana-Maria; Bassi, Amarjeet; Saxena, Priyanka

    2013-09-01

    In recent years, the not too distant exhaustion of fossil fuels is becoming apparent. Apart from this, the combustion of fossil fuels leads to environmental concerns, the emission of greenhouse gases and issues with global warming and health problems. Production of biodiesel from microalgae may represent an attractive solution to the above mentioned problems, and can offer a renewable source of fuel with fewer pollutants. This review presents a compilation of engineering challenges related to microalgae as a source of biodiesel. Advantages and current limitations for biodiesel production are discussed; some aspects of algae cells biology, with emphasis on cell wall composition, as it represents a barrier for fatty acid extraction and lipid droplets are also presented. In addition, recent advances in the different stages of the manufacturing process are included, starting from the strain selection and finishing in the processing of fatty acids into biodiesel. PMID:22804334

  1. Screening of antioxidant activity in microalgae

    OpenAIRE

    Mariana F.G. Assunção; Sandrine da Ressurreição

    2014-01-01

    Due to the toxicity of synthetic antioxidants, the demand for alternative sources of antioxidants over the years has increased. The interest in such compounds is related to their importance in human health and food quality. Microalgae, a group of organisms with high morphological diversity and able to produce a wide variety of biochemical compounds are considered a promising, non expensive source of antioxidant compounds (Guedes et al., 2013a). This work reports the screening of several di...

  2. Microalgae: An Alternative Source of Renewable Energy

    Directory of Open Access Journals (Sweden)

    A. Z. A. Saifullah

    2016-08-01

    Full Text Available This paper presents an overview on the potentiality of microalgae with particular emphasis as a sustainable renewable energy source for biodiesel. One of the most important dilemmas of the modern world is to supply maximal amount of energy with minimal environmental impact. The total energy demand of our planet is increasing with population growth whereas the fossil fuel reserves are dwindling swiftly. Biodiesel produced from biomass is widely considered to be one of the most sustainable alternatives to fossil fuels and a viable means for energy security and environmental and economic sustainability. But as a large area of arable land is required to cultivate biodiesel producing terrestrial plants, it may lead towards food scarcity and deforestation. Microalgae have a number of characteristics that allow the production concepts of biodiesel which are significantly more sustainable than their alternatives. Microalgae possess high biomass productivity, oils with high lipid content, fast growth rates, possibility of utilizing marginal and infertile land, capable of growing in salt water and waste streams, and capable of utilizing solar light and CO2 gas as nutrients.

  3. Applications of Imaging Flow Cytometry for Microalgae.

    Science.gov (United States)

    Hildebrand, Mark; Davis, Aubrey; Abbriano, Raffaela; Pugsley, Haley R; Traller, Jesse C; Smith, Sarah R; Shrestha, Roshan P; Cook, Orna; Sánchez-Alvarez, Eva L; Manandhar-Shrestha, Kalpana; Alderete, Benjamin

    2016-01-01

    The ability to image large numbers of cells at high resolution enhances flow cytometric analysis of cells and cell populations. In particular, the ability to image intracellular features adds a unique aspect to analyses, and can enable correlation between molecular phenomena resulting in alterations in cellular phenotype. Unicellular microalgae are amenable to high-throughput analysis to capture the diversity of cell types in natural samples, or diverse cellular responses in clonal populations, especially using imaging cytometry. Using examples from our laboratory, we review applications of imaging cytometry, specifically using an Amnis(®) ImageStream(®)X instrument, to characterize photosynthetic microalgae. Some of these examples highlight advantages of imaging flow cytometry for certain research objectives, but we also include examples that would not necessarily require imaging and could be performed on a conventional cytometer to demonstrate other concepts in cytometric evaluation of microalgae. We demonstrate the value of these approaches for (1) analysis of populations, (2) documentation of cellular features, and (3) analysis of gene expression.

  4. Efficient recovery of uranium using genetically improved microalgae; Recuperacion eficaz de uranio utilizando microalgas geneticamente mejoradas

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Rodas, V.; Conde Vilda, E.; Garcia-Balboa, C.

    2015-07-01

    We propose an alternative process for the efficient recovery of dissolved uranium based on genetically improved microalgae. We isolate Chlamydomonas cf. fonticola from a pond extremely contaminated by uranium (∼ 25 ppm) from ENUSA U-mine, Saelices (Salamanca, Spain). After a process of genetic improvement we obtained a strain capable to recover 115 mg of U per g of dry weight, by mean of bio-adsorption on the cell wall (mostly) and intra-cytoplasm bioaccumulation. Such a genetically improved microalgae resist extremes of acidity and pollution, but even its dead biomass is still able to recover a large amount of uranium. (Author)

  5. Magnetic microparticles for harvesting Dunaliella tertiolecta microalgae

    Science.gov (United States)

    Manousakis, Emmanouil; Manariotis, Ioannis D.

    2016-04-01

    Microalgae based biofuels have been considered as a sustainable alternative to traditional fuels due to the higher biomass yield and lipid productivity, and the ability to be cultivated in non arable land making them not antagonistic with food supply chain. Due to the dilute nature of algal cultures and the small size of algae cells, the cost of microalgae harvesting is so far a bottleneck in microalgal based biofuel production. It is estimated that the algal recovery cost is at least 20-30% of the total biomass production cost. Various processes have been employed for the recovery of microalgal biomass, which include centrifugation, gravity separation, filtration, flocculation, and flotation. Recently, magnetophoric harvesting has received increased attention for algal separation, although it has been first applied for algal removal since the mid of 1970s. The magnetic separation process is based on bringing in contact the algal cells with the magnetic particles, and separating them from the liquid by an external magnetic force. The aim of this work was to investigate the harvesting of microalgae cells using Fe3O4 magnetic microparticles (MPs). Dunaliella tertiolecta was selected as a representative for marine microalgae. D. tertiolecta was cultivated under continuous artificial light, in 20 L flasks. Fe3O4 MPs were prepared by microwave irradiation of FeSO4 7H2O in an alkaline solution. Numerous batch and flow-through experiments were conducted in order to investigate the effect of the magnetic material addition on microalgae removal. Batch experiments were conducted examining different initial algal and MPs concentration, and algal culture volume. Flow-through experiments were conducted in a laboratory scale column made of Plexiglass. External magnetic field was applied by arranging at various points across the column length NdFeB magnets. Algal removal in flow-through experiments ranged from 70 to 85% depending on the initial MPs concentration and the hydraulic

  6. Enzyme assisted protein extraction from rapeseed, soybean, and microalgae meals

    NARCIS (Netherlands)

    Sari, Y.W.; Bruins, M.E.; Sanders, J.P.M.

    2013-01-01

    Oilseed meals that are by-products from oil production are potential resources for protein. The aim of this work is to investigate the use of enzymes in assisting in the extraction of protein from different oilseed meals, namely rapeseed, soybean, and microalgae meals. In addition, microalgae withou

  7. Chemical Profiles of Microalgae with Emphasis on Lipids: Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J. R.; Tillett, D. M.; Suen, Y.; Hubbard, J.; Tornabene, T. G.

    1986-02-01

    This final report details progress during the third year of this subcontract. The overall objective of this subcontract was two fold: to provide the analytical capability required for selecting microalgae strains with high energy contents and to develop fundamental knowledge required for optimizing the energy yield from microalgae cultures. The progress made towards these objectives during this year is detailed in this report.

  8. Techno-economical evaluation of protein extraction for microalgae biorefinery

    NARCIS (Netherlands)

    Sari, Y.W.; Sanders, J.P.M.; Bruins, M.

    2016-01-01

    Due to scarcity of fossil feedstocks, there is an increasing demand for biobased fuels. Microalgae are considered as promising biobased feedstocks. However, microalgae based fuels are not yet produced at large scale at present. Applying biorefinery, not only for oil, but also for other components

  9. Lipid profiling of some authotrophic microalgae grown on waste water

    DEFF Research Database (Denmark)

    Safafar, Hamed; Jacobsen, Charlotte; Møller, Per

    that microalgae-biomass can be used as an alternative valuable resource in fish feed. In this work, 10 fresh water and marine microalgae from Chlorella, Scenedesmus, Haematococcus, Nannochloropsis, Nannochloropsis and Dunialiella species grown in waste water in Kalundborg micro algal facility were harvested...

  10. PRODUCCIÓN DE BIODIESEL A PARTIR DE MICROALGAS: PARÁMETROS DEL CULTIVO QUE AFECTAN LA PRODUCCIÓN DE LÍPIDOS Biodiesel Production from Microalgae: Cultivation Parameters that Affect Lipid Production

    OpenAIRE

    MARTHA TRINIDAD ARIAS PEÑARANDA; ALFREDO DE JESÚS MARTÍNEZ ROLDÁN; ROSA OLIVIA CAÑIZARES VILLANUEVA

    2013-01-01

    Las microalgas poseen la capacidad para mitigar las emisiones de CO2 y producir lípidos, por lo que se consideran con potencial para la obtención de biocombustibles de tercera generación. La presente revisión proporciona información actualizada de la influencia de las condiciones de cultivo, sobre la obtención de lípidos con una productividad elevada y perfil adecuado para la producción de biodiesel, se proporciona una síntesis de resultados de investigaciones realizadas en los últimos 13 año...

  11. Novel approaches of producing bioenergies from microalgae: A recent review.

    Science.gov (United States)

    Tan, Chung Hong; Show, Pau Loke; Chang, Jo-Shu; Ling, Tau Chuan; Lan, John Chi-Wei

    2015-11-01

    Microalgae have caught the world's attention for its potential to solve one of the world's most pressing issues-sustainable green energy. Compared to biofuels supplied by oil palm, rapeseed, soybean and sugar cane, microalgae alone can be manipulated to generate larger amounts of biodiesel, bioethanol, biohydrogen and biomass in a shorter time. Apart from higher productivity, microalgae can also grow using brackish water on non-arable land, greatly reducing the competition with food and cash crops. Hence, numerous efforts have been put into the commercialisation of microalgae-derived biofuel by both the government and private bodies. This paper serves to review conventional and novel methods for microalgae culture and biomass harvest, as well as recent developments in techniques for microalgal biofuel production.

  12. Novel approaches of producing bioenergies from microalgae: A recent review.

    Science.gov (United States)

    Tan, Chung Hong; Show, Pau Loke; Chang, Jo-Shu; Ling, Tau Chuan; Lan, John Chi-Wei

    2015-11-01

    Microalgae have caught the world's attention for its potential to solve one of the world's most pressing issues-sustainable green energy. Compared to biofuels supplied by oil palm, rapeseed, soybean and sugar cane, microalgae alone can be manipulated to generate larger amounts of biodiesel, bioethanol, biohydrogen and biomass in a shorter time. Apart from higher productivity, microalgae can also grow using brackish water on non-arable land, greatly reducing the competition with food and cash crops. Hence, numerous efforts have been put into the commercialisation of microalgae-derived biofuel by both the government and private bodies. This paper serves to review conventional and novel methods for microalgae culture and biomass harvest, as well as recent developments in techniques for microalgal biofuel production. PMID:25728066

  13. Colloid's influences on microalgae growth as a potential environmental factor

    Institute of Scientific and Technical Information of China (English)

    赵新淮; 张正斌; 刘莲生

    2003-01-01

    The role of colloid as "colloid pump" in the ocean is well known. The important influence of colloid in seawater on the growth of microalga was found in our 1999-2000 study. Colloid concentrates were obtained by employing a cross-flow filtration systen to ultrafilter seawater (which had been pre-filtrated by 0.45 μm acetate cellulose membrane) successively with different membranes. Ultrafiltration retentions (we called them colloid concentrates ) together with control sample ( seawater without colloid) were then inoculated with two species of microalgae and cultivated in selected conditions. Monitoring of microalgae growth during cultivation showed that all colloid concentrates had obvious influence on the growth of the microalgae studied. Addition of Fe(OH)3 colloid or organic colloid (protein or carbohydrate) to the control sample enhanced the microalgae's growth.

  14. Efecto del Cromo Hexavalente y Trivalente sobre el Crecimiento de Escherichia coli ATCC 35218 Effects of Hexavalent and Trivalent Chromium on the Growth of Escherichia coli ATCC 35218

    Directory of Open Access Journals (Sweden)

    Ricardo R Azario

    2010-01-01

    Full Text Available Se estudió el efecto de cromo (VI y (III sobre el crecimiento de Escherichia coli ATCC 35218 con el fin de determinar la toxicidad de estas especies químicas. El estudio fue realizado en dos condiciones experimentales: soluciones unimetal de cromo (III o VI y en soluciones multimetal conteniendo además plomo y cadmio. Se observa que el cromo hexavalente inhibe el crecimiento de Escherichia coli, cuando se encuentra en un rango de concentración de 25 a 100 ppm, similar al de efluentes industriales, y que dicho efecto es potenciado por la presencia de plomo, que per se no modifica la viabilidad bacteriana. Por otro lado, las concentraciones bajas de cromo (VI, 0.05 - 5 ppm no alteran el crecimiento pero producen una estimulación en presencia de plomo o cadmio. La forma trivalente de cromo no modifica el crecimiento bacteriano a concentraciones bajas (25 a 100 ppm pero causa una estimulación a concentraciones más altas (200 a 400 ppm.The effect of chromium (III and (VI on the growth of Escherichia coli ATCC 35218 was studied to determine the toxicity of these chemical species. The study was performed in two experimental conditions: single chromium solutions (III or VI and multimetal solutions containing chromium and either lead or cadmium. Hexavalent chromium, at concentrations from 25 to 100 ppm, similar to those found in industrial effluents, inhibits the growth of Escherichia coli. This inhibitory effect is increased by the presence of lead, which does not modify per se the bacterial viability. On the other hand, low concentrations of chromium (VI, 0.05-5 ppm do not alter bacterial growth but cause stimulation in the presence of either lead or cadmium. The trivalent form of chromium does not modify the bacterial growth at low concentrations (25 to 100 ppm but causes stimulation at high concentrations (200 to 400 ppm.

  15. PRODUCCIÓN DE BIODIESEL A PARTIR DE MICROALGAS: PARÁMETROS DEL CULTIVO QUE AFECTAN LA PRODUCCIÓN DE LÍPIDOS Biodiesel Production from Microalgae: Cultivation Parameters that Affect Lipid Production

    Directory of Open Access Journals (Sweden)

    MARTHA TRINIDAD ARIAS PEÑARANDA

    2013-04-01

    Full Text Available Las microalgas poseen la capacidad para mitigar las emisiones de CO2 y producir lípidos, por lo que se consideran con potencial para la obtención de biocombustibles de tercera generación. La presente revisión proporciona información actualizada de la influencia de las condiciones de cultivo, sobre la obtención de lípidos con una productividad elevada y perfil adecuado para la producción de biodiesel, se proporciona una síntesis de resultados de investigaciones realizadas en los últimos 13 años en diversas partes del mundo. En la literatura consultada, los autores concluyen que aunque el comportamiento de las microalgas ante condiciones de estrés fisiológico es variable entre especies; la limitación de nutrientes especialmente nitrógeno y fósforo, asociado al crecimiento heterotrófico o a altas intensidades luminosas en fototrofía se consideran como las estrategias más eficientes para incrementar el contenido de lípidos en las microalgas, en particular de triglicéridos constituidos por ácidos grasos saturados y monoinsaturados, ideales para la producción de biodiesel. De igual forma, señalan que la presencia de pequeñas cantidades de CO2 y la cosecha de la biomasa en la fase estacionaria de crecimiento, incrementan el contenido de lípidos y disminuyen el número de insaturaciones de los ácidos grasos que lo conforman.The microalgae have the capacity to mitigate CO2 emissions and to produce lipids, which are considered with potential to obtain third-generation biofuel. This review provides updated information of the influence of culture conditions on the lipids production with high productivity and profile suitable for the biodiesel production. This document presents a compilation of research conclusions over the last 13 years around the world. In the literature consulted, the authors conclude that although the behavior of microalgae at physiological stress conditions, varies between species; the nutrients limitation

  16. Photo-biotechnological hydrogen production with microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Lehr, F.; Posten, C. [Inst. fuer Bio- und Lebensmitteltechnik, Univ. Karlsruhe (Germany); Renz, A.; Schaub, G. [Engler-Bunte-Inst., Univ. Karlsruhe (Germany)

    2008-07-01

    Some types of unicellular green algae have evolved the ability to use solar energy to produce hydrogen by splitting water. Compared to photosynthesis with terrestrial plants, microalgal hydrogen production exhibits higher photo conversion efficiencies, very low water demands, and no competition with agriculture for arable land use. The overall process includes microalgae growth by photosynthesis and subsequent hydrogen production. The main challenge in process development is the design of photo bioreactors with minimum energy demand for mixing and liquid handling and maximum overall efficiency. In an ongoing research project, process engineering fundamentals are presently being investigated in order to allow more accurate process design and cost estimates. (orig.)

  17. TUBULAR PHOTOBIOREACTOR FOR MICROALGAE BIODIESEL PRODUCTION

    OpenAIRE

    Nkongolo Mulumba; Ihab H. Farag

    2012-01-01

    Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year). However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR) was designed and achieved a ten times increase in algae concentration. It produced 1g of d...

  18. Stakeholder perceptions of biofuels from microalgae

    International Nuclear Information System (INIS)

    In this paper we focus on stakeholder views around the development of advanced biofuels from microalgae. Research for the development of microalgal-derived biofuels was initiated by the US Department of Energy (DOE) more than 30 years ago. However, interest in this eco-innovation has been growing significantly over the last five years in various countries. The high productivity of algae indicates that algal biofuels could contribute to reduce our dependence on fossil fuels while avoiding the undesired impacts of first generation biofuels. There are still numerous challenges that need nevertheless to be addressed. The aim of this paper is to explore stakeholder perceptions of the current barriers and opportunities associated with this promising emergent technology. - Research highlights: → There are still many questions about how microalgae biofuels will reduce our demand of fossil fuels. → Many of the obstacles discussed by participants are related to the technological and economic barriers. → There are still competing visions on the aspects of the technology where efforts have to be applied. → Years of intensive, continuous and large-scale research and a favorable environment are needed. → The careful protection of the innovation may avoid failure experiences.

  19. Emergent Sources of Prebiotics: Seaweeds and Microalgae

    Directory of Open Access Journals (Sweden)

    Maria Filomena de Jesus Raposo

    2016-01-01

    Full Text Available In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen.

  20. Emergent Sources of Prebiotics: Seaweeds and Microalgae

    Science.gov (United States)

    de Jesus Raposo, Maria Filomena; de Morais, Alcina Maria Miranda Bernardo; de Morais, Rui Manuel Santos Costa

    2016-01-01

    In recent years, scientists have become aware that human microbiota, in general, and gut microbiota, in particular, play a major role in human health and diseases, such as obesity and diabetes, among others. A large number of evidence has come to light regarding the beneficial effects, either for the host or the gut microbiota, of some foods and food ingredients or biochemical compounds. Among these, the most promising seem to be polysaccharides (PS) or their derivatives, and they include the dietary fibers. Some of these PS can be found in seaweeds and microalgae, some being soluble fibers, such as alginates, fucoidans, carrageenans and exopolysaccharides, that are not fermented, at least not completely, by colonic microbiota. This review gives an overview of the importance of the dietary fibers, as well as the benefits of prebiotics, to human health. The potential of the PS from marine macro- and microalgae to act as prebiotics is discussed, and the different techniques to obtain oligosaccharides from PS are presented. The mechanisms of the benefits of fiber, in general, and the types and benefits of algal fibers in human health are highlighted. The findings of some recent studies that present the potential effects of prebiotics on animal models of algal biomass and their extracts, as well as oligo- and polysaccharides, are presented. In the future, the possibility of using prebiotics to modulate the microbiome, and, consequently, prevent certain human diseases is foreseen. PMID:26828501

  1. Biodiesel de microalgas: avanços e desafios Biodiesel from microalgae: progress and challenges

    OpenAIRE

    André Luiz Custódio Franco; Ivon Pinheiro Lôbo; Rosenira Serpa da Cruz; Cláudia Maria Luz Lapa Teixeira; José Adolfo de Almeida Neto; Rafael Silva Menezes

    2013-01-01

    Microalgae biomass has been described by several authors as the raw material with the greatest potential to meet the goals of replacing petroleum diesel by biodiesel while not competing with arable land suitable for food production. Research groups in different countries are seeking the most appropriate production model for productivity, economic viability and environmental sustainability. This review focused on recent advances and challenges of technology for the production of biodiesel from...

  2. Determinación de la adsorción de cadmio mediante isotermas de adsorción en suelos agrícolas venezolanos Determination of the adsorption of cadmium by adsorption isotherms in agricultural soils venezuelans

    Directory of Open Access Journals (Sweden)

    Nereida Sánchez

    2011-04-01

    Full Text Available El cadmio es un metal pesado que tiende a acumularse en la superficie del suelo. En los últimos años, las actividades antropogénicas han ocasionado un incremento en los niveles de este metal en suelos agrícolas generando gran preocupación ambiental debido a su movilidad y lixiviación en el perfil del suelo y a la facilidad con que es absorbido por las plantas. El objetivo de este trabajo fue determinar la capacidad de adsorción de cadmio, de cuatro suelos venezolanos de uso agrícola con diferencias texturales. Para determinar la capacidad de adsorción del metal en cada suelo, inicialmente se determinó el tiempo óptimo de agitación; el cual fue de 2 horas y la relación suelo-solución enriquecedora de Cd; la cual fue de 1:50. Con estos parámetros se elaboraron las isotermas de adsorción para los suelos y se compararon los modelos de Freundlich y Langmuir. Los resultados mostraron que el modelo matemático de Freundlich es el que mejor describe la cinética de la reacción y la capacidad de adsorción de Cd por los suelos, siendo los que poseen mayores contenidos de arcilla, MO y pH ácidos los de mayor capacidad de adsorción.Cadmium is a heavy metal which tends to accumulate in the soil surface. In recent years, anthropogenic activities have caused an increase of the levels of this metal in agricultural soils causing great environmental concern due to their mobility and leaching in the soil profile and the ease way to be absorbed by plants. The purpose of this study was to determine the adsorption capacity of cadmium in four Venezuelan agricultural soils with different texture. To determine the adsorption capacity of Cd in each soil, first of all the optimal time of stirring was determined, which was two hours and the soilenriching solution of Cd, which was (1/50. With these parameters, cadmium adsorption isotherms for all soils were developed and compared with Freundlich and Langmuir models. The data showed that the Freundlich

  3. Addendum to Microalgae Culture Collection 1986-1987

    Energy Technology Data Exchange (ETDEWEB)

    Johansen, J. R.; Lemke, P.; Nagle, N. J.; Chelf, P.; Roessler, P. G.; Galloway, R.; Toon, S.

    1987-12-01

    The SERI Microalgae Culture Collection was established in support of the U.S. Department of Energy Biofuels and Municipal Waste Technology Program to provide a repository for strains identified or developed for mass culture biomass production.

  4. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae.

    NARCIS (Netherlands)

    R.H. Wijffels; O. Kruse; K.J. Hellingwerf

    2013-01-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments. Cyanobacteria are promising host organisms fo

  5. Techno-Economic Assessment of Micro-Algae Production Systems

    OpenAIRE

    Hoffman, Justin

    2016-01-01

    Global oil consumption is rising at an unprecedented rate renewing interest in alternative fuels. Micro-algae represents a promising feedstock due to inherent advantages such as high solar energy efficiencies, large lipid fractions, and utilization of various waste streams including industrial flue gas. Current technological challenges have limited the commercial viability of microalgae based biofuel production systems. This study directly evaluates and compares the economic viability of biom...

  6. Low-cost harvesting of microalgae biomass from water

    OpenAIRE

    Bejor, E.S.; Mota, C.; Ogarekpe, N.M.; Emerson, K.U.; Ukpata, J.

    2013-01-01

    Microalgae harvesting is known to be a major problem in the water industry. This is attributed to the minute nature of the algae cells and the often low concentration of the species in water and wastewater. While various chemical and mechanical harvesting techniques have been developed for algae harvesting, their application have been limited by prohibitive costs. There is also the disadvantage of not utilising the harvested microalgae as feedstock when it has accumulated significant amounts ...

  7. DEVELOPMENT OF REFINERY CO2 CAPTURE BY MICROALGAE

    OpenAIRE

    Keresztényi, István; Babos, Katalin; Bohács, György; Siklósi, Tamás

    2013-01-01

    As a significant emitter of carbon-dioxide in the region MOL Hungarian Oil & Gas Plc. has launched an extensive research program associated with carbon capture and utilization. Research is focused on the utilization of carbon dioxide as a feedstock for biological processes such as greenhouse growing and microalgae cultivation for further industrial applications. For the development of microalgae related technologies MOL Downstream Development has established collaboration with several scienti...

  8. Microalgal CO2 sequestering – Modeling microalgae production costs

    International Nuclear Information System (INIS)

    Highlights: ► Microalgae production costs were modeled as a function of specific expenses. ► The effects of uncontrollable expenses/factors were incorporated into the model. ► Modeled microalgae production costs were in the range $102–1503 t−1 ha−1 y−1. - Abstract: Microalgae CO2 sequestering facilities might become an industrial reality if microalgae biomass could be produced at cost below $500.00 t−1. We develop a model for estimation of total production costs of microalgae as a function of known production-specific expenses, and incorporate into the model the effects of uncontrollable factors which affect known production-specific expenses. Random fluctuations were intentionally incorporated into the model, consequently into generated cost/technology scenarios, because each and every logically interconnected equipment/operation that is used in design/construction/operation/maintenance of a production process is inevitably subject to random cost/price fluctuations which can neither be eliminated nor a priori controlled. A total of 152 costs/technology scenarios were evaluated to find 44 scenarios in which predicted total production costs of microalgae (PTPCM) was in the range $200–500 t−1 ha−1 y−1. An additional 24 scenarios were found with PTCPM in the range of $102–200 t−1 ha−1 y−1. These findings suggest that microalgae CO2 sequestering and the production of commercial compounds from microalgal biomass can be economically viable venture even today when microalgae production technology is still far from its optimum.

  9. Biodiesel de microalgas: avanços e desafios

    Directory of Open Access Journals (Sweden)

    André Luiz Custódio Franco

    2013-01-01

    Full Text Available Microalgae biomass has been described by several authors as the raw material with the greatest potential to meet the goals of replacing petroleum diesel by biodiesel while not competing with arable land suitable for food production. Research groups in different countries are seeking the most appropriate production model for productivity, economic viability and environmental sustainability. This review focused on recent advances and challenges of technology for the production of biodiesel from microalgae, including the procedures used to obtain biomass.

  10. Cultivating Microalgae in Domestic Wastewater for Biodiesel Production

    OpenAIRE

    Soha S.M. MOSTAFA; Shalaby, Emad A; Ghada I. MAHMOUD

    2012-01-01

    The objective of this study was to evaluate the growth of nine species of microalgae (green and blue green microalgae) on domestic waste water samples obtained from Zenein Waste Water Treatment Plant (ZWWTP), Giza governorate, Egypt. The species were cultivated in different kind of waste water; before treatment; after sterilization; with nutrients with sterilization and with nutrients without sterilization. The experiment was conducted in triplicate and cultures were incubated at 25�1�C under...

  11. Biodiesel Production from Microalgae by Extraction – Transesterification Method

    OpenAIRE

    Nguyen Thi Phuong Thao; Nguyen Thanh Tin; Bui Xuan Thanh

    2013-01-01

    The environmental impact of using petroleum fuels has led to a quest to find a suitable alternative fuel source. In this study, microalgae were explored as a highly potential feedstock to produce biodiesel fuel. Firstly, algal oil is extracted from algal biomass by using organic solvents (n–hexan).  Lipid is contained in microalgae up to 60% of their weight. Then, Biodiesel is created through a chemical reaction known as transesterification between algal oil and alcohol (methanol) with ...

  12. Microalgae as Sustainable Renewable Energy Feedstock for Biofuel Production

    OpenAIRE

    Srikanth Reddy Medipally; Fatimah Md. Yusoff; Sanjoy Banerjee; Shariff, M

    2015-01-01

    The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technical...

  13. Analysis of Extraction and Transesterification Conditions for Phaeodactylum Tricornutum Microalgae

    OpenAIRE

    Jose Lius Salgueiro; Ángeles Cancela; Ángel Sánchez; Rocío Maceiras; Leticia Pérez

    2015-01-01

    An increasing global demand for a biologically produced energy source has emerged due to the exhausted usage of non-renewable petroleum-derived fuels. Microalgae are a promising feedstock for biofuels because of their capability to produce lipids. In this paper, two operations for biodiesel production were studied from Phaeodactylum Tricornutum microalgae. This marine diatom shows a big potential to produce biodiesel due to its fast growth and lipid accumulation ability. In this research, fir...

  14. Microalgae Isolation and Selection for Prospective Biodiesel Production

    OpenAIRE

    Van Thang Duong; Yan Li; Ekaterina Nowak; Schenk, Peer M.

    2012-01-01

    Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products ar...

  15. Food and fuel microalgae applications: insights from portuguese experience [Resumo

    OpenAIRE

    Batista, Ana Paula; Nobre, Beatriz P.; de Oliveira, A C; Passarinho, Paula C.; Marques, Paula Alexandra; Marques, Isabel Paula Ramos; Ribeiro, Belina; Raymundo, Anabela; Sousa, Isabel; de Gouveia, L.

    2015-01-01

    Microalgae have a wide range of application fields, from food to fuels, to pharmaceuticals & fine chemicals, aquaculture and environmental bioremediation, among others. Spirulina and Chlorella have been used as food sources since ancient times, due to their high and balanced nutritional value. Our research group in Lisbon has developed a range of food products (emulsions, gelled desserts, biscuits and pastas) enriched with freshwater and marine microalgae (Spirulina, Chlorella, Haematococcus,...

  16. Allelopathy as a potential strategy to improve microalgae cultivation

    OpenAIRE

    Bacellar Mendes, Leonardo Brantes; Vermelho, Alane Beatriz

    2013-01-01

    One of the main obstacles for continuous productivity in microalgae cultivation is the presence of biological contaminants capable of eliminating large numbers of cells in a matter of days or even hours. However, a number of strategies are being used to combat and prevent contamination in microalgae cultivation. These strategies include the use of extreme conditions in the culture media such as high salinity and high pH to create an unfavorable environment for the competitive organisms or pre...

  17. Continuous culture methodology for the screening of microalgae for oil

    OpenAIRE

    del Rio, E; Armendáriz, Ana; García-Gómez, Elena; García-González, Mercedes; Guerrero, Miguel G.

    2015-01-01

    A basic criterion in the selection of microalgae suitable as source of oil for biodiesel should be their actual capacity to produce lipids or, more properly, the fatty acid yield. Performance assessment of ten preselected microalgae under both batch and continuous culture points to the latter approach as the most adequate for evaluating fatty acid productivity. Differences were patent in continuous culture among strains that otherwise had analogous oil accumulation potential un...

  18. Microalgae Isolation and Selection for Prospective Biodiesel Production

    OpenAIRE

    Schenk, Peer M.; Ekaterina Nowak; Van Thang Duong; Yan Li

    2012-01-01

    Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products ar...

  19. Microalgae as sustainable renewable energy feedstock for biofuel production.

    Science.gov (United States)

    Medipally, Srikanth Reddy; Yusoff, Fatimah Md; Banerjee, Sanjoy; Shariff, M

    2015-01-01

    The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technically and economically viable and cost competitive, require no additional lands, require minimal water use, and mitigate atmospheric CO2. However, commercial production of microalgae biodiesel is still not feasible due to the low biomass concentration and costly downstream processes. The viability of microalgae biodiesel production can be achieved by designing advanced photobioreactors, developing low cost technologies for biomass harvesting, drying, and oil extraction. Commercial production can also be accomplished by improving the genetic engineering strategies to control environmental stress conditions and by engineering metabolic pathways for high lipid production. In addition, new emerging technologies such as algal-bacterial interactions for enhancement of microalgae growth and lipid production are also explored. This review focuses mainly on the problems encountered in the commercial production of microalgae biofuels and the possible techniques to overcome these difficulties. PMID:25874216

  20. Microalgae as Sustainable Renewable Energy Feedstock for Biofuel Production

    Directory of Open Access Journals (Sweden)

    Srikanth Reddy Medipally

    2015-01-01

    Full Text Available The world energy crisis and increased greenhouse gas emissions have driven the search for alternative and environmentally friendly renewable energy sources. According to life cycle analysis, microalgae biofuel is identified as one of the major renewable energy sources for sustainable development, with potential to replace the fossil-based fuels. Microalgae biofuel was devoid of the major drawbacks associated with oil crops and lignocelluloses-based biofuels. Algae-based biofuels are technically and economically viable and cost competitive, require no additional lands, require minimal water use, and mitigate atmospheric CO2. However, commercial production of microalgae biodiesel is still not feasible due to the low biomass concentration and costly downstream processes. The viability of microalgae biodiesel production can be achieved by designing advanced photobioreactors, developing low cost technologies for biomass harvesting, drying, and oil extraction. Commercial production can also be accomplished by improving the genetic engineering strategies to control environmental stress conditions and by engineering metabolic pathways for high lipid production. In addition, new emerging technologies such as algal-bacterial interactions for enhancement of microalgae growth and lipid production are also explored. This review focuses mainly on the problems encountered in the commercial production of microalgae biofuels and the possible techniques to overcome these difficulties.

  1. Analysis of Extraction and Transesterification Conditions for Phaeodactylum Tricornutum Microalgae

    Directory of Open Access Journals (Sweden)

    Jose Lius Salgueiro

    2015-06-01

    Full Text Available An increasing global demand for a biologically produced energy source has emerged due to the exhausted usage of non-renewable petroleum-derived fuels. Microalgae are a promising feedstock for biofuels because of their capability to produce lipids. In this paper, two operations for biodiesel production were studied from Phaeodactylum Tricornutum microalgae. This marine diatom shows a big potential to produce biodiesel due to its fast growth and lipid accumulation ability. In this research, first the microalgae was harvesting using an inorganic flocculant as copper (II sulphate (CuSO4. When the dose was 200 mg/L, the microalgae recovery was close 83% in the first five minutes. After that, the microalgal oil was separated by ultrasound extraction process, using ethanol as solvent. This allows to analyze the oil content of the microalgae which is used later in the transesterification. The obtained lipid content was 38% wt. Temperature variations were observed in this process. Finally, a direct transesterification reaction took place with base catalysis by three ways: traditional, microwave assisted and ultrasound assisted. Direct transesterification microwave assisted achieved 52% conversion to biodiesel versus 16% for the traditional method. However, the best performance (90% was obtained for ultrasound assisted transesterification. Keywords: microalgae; harvesting; transesterification: microwave; ultrasound; extraction.

  2. Methane production from marine microalgae Isochrysis galbana.

    Science.gov (United States)

    Santos, Nathalia O; Oliveira, Suzana M; Alves, Larissa C; Cammarota, Magali C

    2014-04-01

    Methane production from marine microalgae Isochrysis galbana was assessed before and after mechanical and chemical pretreatments. Mechanical pretreatment resulted in a 61.7% increase in soluble Chemical Oxygen Demand. Different hydrolysis conditions were evaluated by varying temperature - T, sulfuric acid concentration - AC and biomass suspension concentration (measured as particulate COD - CODp) using an experimental design. The most significant interaction occurred between AC and T and the hydrolysis condition that showed the best result in the anaerobic digestion step was the condition at 40°C with addition of 0.2% (v/v) acid for 16h (9.27LCH4/kgVS). The low methane yields were attributed to inhibitory sodium concentrations for anaerobic digestion. Eliminating inhibitory sodium in the anaerobic digestion by biomass prewashing, there was a 71.5% increase in methane yield for biomass after acid hydrolysis, demonstrating the need for pretreatment and reduction in sodium concentration in the anaerobic digestion.

  3. TUBULAR PHOTOBIOREACTOR FOR MICROALGAE BIODIESEL PRODUCTION

    Directory of Open Access Journals (Sweden)

    Nkongolo Mulumba

    2012-02-01

    Full Text Available Biodiesel production from algae is a promising technique. Microalgae have the potential to produce 5,000-15,000 gallons of biodiesel/(acre-year. However, there are challenges; these include high yieldof algae biomass with high lipid content and the effective technique to harvest the grown algae, extract the algal oil and transesterify the oil to biodiesel. In this project Tubular PhotoBioReactor (TPBR was designed and achieved a ten times increase in algae concentration. It produced 1g of dry algal biomass per liter of medium within 12 days, with a lipid content of 12% approximately. Healthy algal culture grew well in the TPBR reaching 56x106 cells/mL of culture medium. The 10 fold increase is higher than those reported for open ponds and helical photobioreactor.

  4. Review Paper on Cell Membrane Electroporation of Microalgae using Electric Field Treatment Method for Microalgae Lipid Extraction

    Science.gov (United States)

    Joannes, C.; Sipaut, C. S.; Dayou, J.; Yasir, S. M.; Mansa, R. F.

    2015-04-01

    The paper reviews the recent studies on the lipid extraction of microalgae that mainly highlighted on the cell disruption method using variety of microalgae species. Selection of cell disruption method and devices are crucial in order to achieve the highest extraction percentage of lipid and other valuable intracellular (proteins, carotenoids and chlorophylls) from microalgae cell. Pulsed electric field (PEF) and electrochemical lysis methods were found to be potential for enhancing the extraction efficiencies either conducted in single step extraction or used as pre-treatment followed by conventional extraction method. The PEF technology capable to extract lipid as high as 75%. While, electrochemical lysis treatment capable to extract lipid approximately 93% using Stainless Steel (SS) and Ti/IrO2 as the cathode and anode electrode respectively. PEF technology and electrochemical lysis are still considered to be a new method for microalgae lipid extraction and further investigation can still be done for better improvement of the system.

  5. Cadmio en sangre y su relación con el consumo de tabaco en una población laboral hospitalaria Blood cadmium and its relationship with smoking in a hospital employee population Cádmio presente no sangue e a sua relação com o consumo de tabaco numa população de trabalhadores de um hospital

    Directory of Open Access Journals (Sweden)

    Cristina Fernández Pérez

    2012-12-01

    Full Text Available La exposición de la población general al cadmio es un problema de salud pública, siendo las principales fuentes tanto el consumo de tabaco como la exposición al humo del mismo.El objetivo de este trabajo fue determinar la concentración de cadmio en sangre en una población laboral hospitalaria y su asociación con el consumo de tabaco.Se administró el cuestionario PESA® a 395 sujetos. El cadmio en sangre se midió por espectrometría de absorción atómica con atomización electrotérmica.La mediana de cadmio en sangre fue 0,29 μg/L. La mediana de cadmio de los fumadores (0,83 μg/L fue la más elevada y la de los exfumadores (0,31 μg/L fue a su vez más elevada que la de aquellos que nunca habían fumado (0,21 μg/L. Dentro del grupo de fumadores, se observó una asociación entre la concentración de cadmio y el número de cigarrillos inhalados.En el grupo de exfumadores se observó una asociación con el número de cigarrillos que habían consumido y una correlación negativa entre el tiempo transcurrido desde el abandono del hábito tabáquico y la concentración de cadmio en sangre.Dentro del grupo de los que nunca habían fumado, se observó una diferencia entre la concentración de cadmio de los fumadores pasivos (0,24 μg/L y los que no lo eran (0,20 μg/L.La concentración de cadmio en sangre se relacionó con el consumo de tabaco. Son necesarios más estudios para confirmar el hallazgo de concentraciones de cadmio más elevadas en los fumadores pasivos.Exposure to cadmium is a public health problem due to the broad exposure to this toxic substance among the general population. The main sources of exposure are both tobacco consumption and tobacco smoke.The aim of this study was to determine the blood cadmium concentration in an employee population drawn from our hospital and its association with tobacco consumption.The exposure questionnaire PESA® was administered to 395 employees. Blood cadmium was measured by electrothermal

  6. Efeito do meio Erd Schreiber no cultivo das microalgas Dunaliella salina, Tetraselmis chuii e Isochrysis galbana = Erd Schreiber medium effect in culture of microalgae Dunaliella salina, Tetraselmis chuii and Isochrysis galbana

    Directory of Open Access Journals (Sweden)

    Vera Lucia Mota Klein

    2006-04-01

    Full Text Available As microalgas são utilizadas como fonte de alimento em aqüicultura. Neste trabalho cultivaram-se D. salina, T. chuii e I. galbana. O objetivo do trabalho consistiu em determinar o efeito do meio Erd Schreiber sobre o seu crescimento. Iniciou-se o cultivo com a mistura de 200 mg de Na2HPO4,7H2O, 100 mg de NaNO3 e 50 mL de extrato de solo. No monitoramento, manteve-se a temperatura entre 24 - 28 oC, a salinidade a 34 ppt, à iluminação constante, a densidade celular com uma câmara de Neubauer e um microscópio binocular modelo ZEISS. Como resultado, I. galbana, D. salina e T. chuii atingiram 969 104 cel/mL, 457 x 104 cel/mL e 258,66 x 104 cel/mL, respectivamente, e oscoeficientes angulares b foram 3,76 x 104 cel./mL/dia, 6,84 x 104 cel./mL/dia e 2,08 x 104 cel./mL/dia respectivamente, indicando bom desempenho de todas as microalgas no meio Erd Shreiber.The microalgae is used as food source in aqüicultura. In this work they had cultivated D. salina , T. chuii and I. galbana . The objective of the work is to determine the effect of Erd Schreiber´s culture medium on the microalgae growth. The culture initiated mixting 200mg of Na2HPO4,7H2O, 100 mg of NaNO3 and 50 mL of soil extract. During the culture the temperature had varied between 24 and 28oC, the salinity was fixed on 34 %o, and the illumination was maintained constant. The assessment of the culture was made by a chamber of Neubauer and a binocular microscope ZEISS model. As result I. galbana D. salina and T.chuii reached 969 104 cel/mL, 457 x 104cel/mL and 258,66 x 104 cel/mL respectively and as angular coefficient 3,76 x 104 cel/mL/dia, 6,84 x 104 cel/mL/dia and 2,08 104 x cel/mL/dia respectively, showing good answer of the microalgae to the effect of Erd Schreiber´ s medium.

  7. Effect of Quail Litter Biochar on Productivity of Four New Physic Nut Varieties Planted in Cadmium-Contaminated Soil Efecto del Biocarbón de Cama de Codorniz en la Productividad de Cuatro Variedades Nuevas de Jatrofa Plantadas en Suelo Contaminado con Cadmio

    Directory of Open Access Journals (Sweden)

    Tawadchai Suppadit

    2012-03-01

    Full Text Available Biochar can improve soil structure and water retention, enhance nutrient availability and retention, ameliorate acidity, and reduce heavy metal toxicity to plant roots. In this study, a basin experiment was conducted to investigate the effects of quail litter biochar (QLB on the availability of Cd to physic nut (Jatropha curcas L. plants. QLB was applied to the soil in which four new physic nut varieties (Takfa, Doi Saket, Lao, and Rayong in factorial combinations at four levels (0, 5, 10, and 15 g kg-1 soil to soil that contained 60.8 mg Cd kg-1. After transplanting plant height and canopy radius were measured every 2-mo and the number of leaves and branches at 6-mo, while yield components and Cd residues were measured at 8-mo intervals. The contaminated soil was analyzed for chemical characteristics, nutrients, and Cd residue after the plant harvest. The addition of QLB to soil caused a significant increase in the soil's growth potential and physic nut yield components (P Se ha visto que el biocarbón mejora la estructura del suelo y la retención de agua, mejora la disponibilidad y la retención de nutrientes, controla la acidez y reduce la toxicidad de metales pesados en las raíces de las plantas. En este trabajo se investiga el uso de biocarbón de cama de codorniz (QLB en la disponibilidad de Cd para la planta de jatrofa (Jatropha curcas L. en un estudio de laboratorio. Se realiza una combinación factorial con cuatro variedades nuevas de jatrofa (Takfa, Doi Saket, Lao y Rayong sobre cuatro proporciones de QLB a 0, 5, 10, y 15 g kg-1 añadidos por separado a suelo contaminado con 60,8 mg Cd kg-1. Tras el trasplante se midió la altura de la planta y la cubierta vegetal cada 2 meses, el número de hojas y ramas a los 6 meses y los parámetros de rendimiento así como el residuo de Cd a los 8 meses. A continuación, tras la cosecha de la planta, se analizaron las características químicas, nutrientes y residuo de Cd en el suelo contaminado

  8. Microalgae harvesting in wastewater treatment plants : application of natural techniques for an efficient flocculation

    OpenAIRE

    Gutiérrez Martínez, Raquel

    2016-01-01

    Research of new sources of bioenergy is nowadays driving attention to microalgae. Cost-effective biomass harvesting poses a challenge for full-scale microalgae production for biofuels. In the context of wastewater treatment with microalgae cultures, coagulation-flocculation followed by sedimentation seems to be the most suitable option for microalgae harvesting as low energy and no extra materials are required. The main objective if this PhD thesis was to evaluate and improve the harvesti...

  9. Cationic Starch Synthesis, Development, and Evaluation for Harvesting Microalgae for Wastewater Treatment

    OpenAIRE

    Anthony, Renil John

    2013-01-01

    In the quest for a feedstock for the production of biofuels, microalgae are showing potential. High photosynthetic efficiency, combined with high lipid content and low fresh water requirement, has contributed to the 'biofuels feedstock' status of microalgae. In some communities, microalgae have also been cultivated in wastewater in facultative lagoons to remove phosphorus and nitrogen through the growth of microalgae. With such systems in place, complete biological wastewater treatment can be...

  10. Intensification of microalgae drying and oil extraction process by vapor recompression and heat integration

    OpenAIRE

    Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Kitamura, Yutaka

    2016-01-01

    Reducing energy penalty caused by drying and oil extraction is the most critical challenge in microalgae biodiesel production. In this study, vapor recompression and heat integration are utilized to optimize the performance of wet microalgae drying and oil extraction. In the microalgae drying stage, the hot exhaust stream is recompressed and coupled with wet microalgae to recover the condensate heat. In the oil extraction stage, the exergy rate of recovered solvent is also elevated by compres...

  11. Microalgae as human food: chemical and nutritional characteristics of the thermo-acidophilic microalga Galdieria sulphuraria.

    Science.gov (United States)

    Graziani, Giulia; Schiavo, Simona; Nicolai, Maria Adalgisa; Buono, Silvia; Fogliano, Vincenzo; Pinto, Gabriele; Pollio, Antonino

    2013-01-01

    The use of microalgae as a food source is still poorly developed because of the technical difficulties related to their cultivation and the limited knowledge about their chemical composition and nutritional value. The unicellular red microalga Galdieria sulphuraria has a very high daily productivity and its cultivation under acidic conditions avoided any bacterial contamination. G. sulphuraria can be cultured under autotrophic and heterotrophic conditions: in this study a screening of 43 strains showed that in the latter case a duplication of biomass production was obtained. The proximate composition (protein, carbohydrates, fiber and lipids), the micronutrient content (carotenoids, phycobiliproteins, chlorophylls and vitamins) together with the antioxidant activity of the biomass produced by a selected strain of G. sulphuraria under both cultivation conditions were determined. Results showed that the material is rich in proteins (26-32%) and polysaccharides (63-69%) and poor in lipids. Under heterotrophic cultivation conditions, the lipid moiety mainly contained monounsaturated fatty acids. Among micronutrients, some B group vitamins are present, beta-carotene is the main carotenoid and phycobiliproteins are present under both cultivating conditions. G. sulphuraria proteins are strictly associated with polysaccharide components and therefore not digestible. In the second part of the work, an extraction protocol using Viscozyme L, a commercial enzymatic preparation containing a mixture of polysaccharidases, was developed which made G. sulphuraria proteins a good substrate for human gastrointestinal enzymes. All in all, the data suggested that G. sulphuraria biomass has a potential use as food ingredients both for protein-rich or insoluble dietary fibre-rich applications. The low concentration of lipids and the absence of green color make this microalgae source particularly useful for the addition to many food preparations.

  12. Microalgas, produtos e aplicações Microalgae, products and applications

    Directory of Open Access Journals (Sweden)

    Roberto Bianchini Derner

    2006-12-01

    Full Text Available Nos últimos anos, muito interesse tem sido focado no potencial biotecnológico das microalgas, principalmente devido à identificação de diversas substâncias sintetizadas por estes organismos. A imensa biodiversidade e conseqüente variabilidade na composição bioquímica da biomassa obtida das culturas microalgais, aliadas ao emprego de melhoramento genético e ao estabelecimento de tecnologia de cultivo em grande escala, vêm permitindo que determinadas espécies sejam comercialmente utilizadas. Nesse sentido, cultivos de microalgas têm sido realizados visando à produção de biomassa tanto para uso na elaboração de alimentos quanto para a obtenção de compostos naturais com alto valor no mercado mundial. Dentre os inúmeros compostos extraídos, ou com potencial de exploração comercial, podem ser relacionados ácidos graxos poliinsaturados, carotenóides, ficobilinas, polissacarídeos, vitaminas, esteróis e diversos compostos bioativos naturais (antioxidantes, redutores do colesterol etc., os quais podem ser empregados especialmente no desenvolvimento de alimentos funcionais, por suas propriedades nutricionais e farmacêuticas.In recent years, much interest has been focused on the biotechnological potential of microalgae, mainly due the identification of several substances synthesized by these organisms. The great biodiversity and consequent variability in the biochemical composition of the biomass obtained from the microalgal cultures, allied to the genetic improvement and to the establishment of technology in massive production, have allowed various species to be commercially cultivated. In this sense, microalgae cultivations have been developed aiming at the biomass production not only for use in the food elaboration but also for the obtainment of natural compounds with high value in the world market. Among the main extracted substances, or with potential of commercial exploration, can be related polyunsaturated fatty acids

  13. Ratio between autoflocculating and target microalgae affects the energy-efficient harvesting by bio-flocculation

    NARCIS (Netherlands)

    Salim, S.; Vermuë, M.H.; Wijffels, R.H.

    2012-01-01

    The effect of ratio between autoflocculating and target microalgae in bio-flocculation was studied with emphasis on the recovery, sedimentation rate and energy demand for harvesting the target microalgae. When the autoflocculating microalgae Ettlia texensis, Ankistrodesmus falcatus and Scenedesmus o

  14. Effect of Lignocellulose Related Compounds on Microalgae Growth and Product Biosynthesis: A Review

    OpenAIRE

    Krystian Miazek; Claire Remacle; Aurore Richel; Dorothee Goffin

    2014-01-01

    Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, differe...

  15. Benefits of Microalgae for Human Space Exploration

    Science.gov (United States)

    Verrecchia, Angelique; Bebout, Brad M.; Murphy, Thomas

    2015-01-01

    Algae have long been known to offer a number of benefits to support long duration human space exploration. Algae contain proteins, essential amino acids, vitamins, and lipids needed for human consumption, and can be produced using waste streams, while consuming carbon dioxide, and producing oxygen. In comparison with higher plants, algae have higher growth rates, fewer environmental requirements, produce far less "waste" tissue, and are resistant to digestion and/or biodegradation. As an additional benefit, algae produce many components (fatty acids, H2, etc.) which are useful as biofuels. On Earth, micro-algae survive in many harsh environments including low humidity, extremes in temperature, pH, and as well as high salinity and solar radiation. Algae have been shown to survive inmicro-gravity, and can adapt to high and low light intensity while retaining their ability to perform nitrogen fixation and photosynthesis. Studies have demonstrated that some algae are resistant to the space radiation environment, including solar ultraviolet radiation. It remains to be experimentally demonstrated, however, that an algal-based system could fulfil the requirements for a space-based Bioregenerative Life Support System (BLSS) under comparable spaceflight power, mass, and environmental constraints. Two specific challenges facing algae cultivation in space are that (i) conventional growth platforms require large masses of water, which in turn require a large amount of propulsion fuel, and (ii) most nutrient delivery mechanisms (predominantly bubbling) are dependent on gravity. To address these challenges, we have constructed a low water biofilm based bioreactor whose operation is enabled by capillary forces. Preliminary characterization of this Surface Adhering BioReactor (SABR) suggests that it can serve as a platform for cultivating algae in space which requires about 10 times less mass than conventional reactors without sacrificing growth rate. Further work is necessary to

  16. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work.

  17. Isolation, identification and characterization of an electrogenic microalgae strain.

    Directory of Open Access Journals (Sweden)

    Yicheng Wu

    Full Text Available Extracellular electron transfer involving microbes is important as it closely reflects the ability of cells to communicate with the environment. However, there are few reports on electron transfer mechanisms of pure microalgae and a lack of any model alga to study the transfer processes. In the present study, nine green microalgae species were isolated from wastewater and characterized in terms of their ability to transfer electrons between cells and an electrode. One species showed direct electron transfer via membrane-associated proteins and indirect electron transfer via secreted oxygen. The microalga was identified as Desmodesmus sp. based on phylogenetic analysis and electron microscopy. Electrochemical tests demonstrated that Desmodesmus sp. was able to act as a cathodic microorganism. Stable current densities of -0.24, 35.54 and 170 mA m(-2 were achieved at potentials of +0.2, -0.2 and -0.4 V, respectively, under illumination. Dissolved oxygen concentration measurement showed gradients within the microalgae biofilm: 18.3 mg L(-1 in light decreasing to 4.29 mg L(-1 in the dark. This study diversified the exoelectrogen library and provided a potential model microalga to explore the associated mechanism of extracellular electron transfer.

  18. Isolation, identification and characterization of an electrogenic microalgae strain.

    Science.gov (United States)

    Wu, Yicheng; Guan, Kai; Wang, Zejie; Xu, Bing; Zhao, Feng

    2013-01-01

    Extracellular electron transfer involving microbes is important as it closely reflects the ability of cells to communicate with the environment. However, there are few reports on electron transfer mechanisms of pure microalgae and a lack of any model alga to study the transfer processes. In the present study, nine green microalgae species were isolated from wastewater and characterized in terms of their ability to transfer electrons between cells and an electrode. One species showed direct electron transfer via membrane-associated proteins and indirect electron transfer via secreted oxygen. The microalga was identified as Desmodesmus sp. based on phylogenetic analysis and electron microscopy. Electrochemical tests demonstrated that Desmodesmus sp. was able to act as a cathodic microorganism. Stable current densities of -0.24, 35.54 and 170 mA m(-2) were achieved at potentials of +0.2, -0.2 and -0.4 V, respectively, under illumination. Dissolved oxygen concentration measurement showed gradients within the microalgae biofilm: 18.3 mg L(-1) in light decreasing to 4.29 mg L(-1) in the dark. This study diversified the exoelectrogen library and provided a potential model microalga to explore the associated mechanism of extracellular electron transfer. PMID:24019922

  19. Uptake of uranium from sea water by microalgae

    International Nuclear Information System (INIS)

    The uptake of uranium from aqueous systems especially from sea water by various microalgae was investigated. The freshwater microalgae, Chlorella regularis, Scenedesmus bijuga, Scenedesmus chloreloides, Scenedesmus obliquus, Chlamydomonas angulosa, Chlamydomonas reinhardtii, accumulated relatively large amounts of uranium from the solution containing uranium only. The concentration factors of the above mentioned algae were: Chlorella regularis 3930, Chlamydomonas 2330 - 3400, Scenedesmus 803 - 1920. The uptake of uranium from sea water by Chlorella regularis was inhibited markedly by the co-existence of carbonate ions. Chlorella cells could take up a great quantity of uranium from decarbonated sea water. The uptake of uranium was affected by the pH of sea water, and the amount of uranium absorbed was maximum at pH 5. The experiment was carried out to screen marine microalgae which have the ability to accumulate a large amount of uranium from sea water. The uptake of uranium from sea water by marine microalgae of different species turned out to be in the following decreasing order: Synechococcus > Chlamydomonas >> Chlorella > Dunaliella > Platymonas > Calothrix > Porphyridium. The amount of uranium absorbed differed markedly with different species of marine microalgae. (author)

  20. Nutrient and media recycling in heterotrophic microalgae cultures.

    Science.gov (United States)

    Lowrey, Joshua; Armenta, Roberto E; Brooks, Marianne S

    2016-02-01

    In order for microalgae-based processes to reach commercial production for biofuels and high-value products such as omega-3 fatty acids, it is necessary that economic feasibility be demonstrated at the industrial scale. Therefore, process optimization is critical to ensure that the maximum yield can be achieved from the most efficient use of resources. This is particularly true for processes involving heterotrophic microalgae, which have not been studied as extensively as phototrophic microalgae. An area that has received significant conceptual praise, but little experimental validation, is that of nutrient recycling, where the waste materials from prior cultures and post-lipid extraction are reused for secondary fermentations. While the concept is very simple and could result in significant economic and environmental benefits, there are some underlying challenges that must be overcome before adoption of nutrient recycling is viable at commercial scale. Even more, adapting nutrient recycling for optimized heterotrophic cultures presents some added challenges that must be identified and addressed that have been largely unexplored to date. These challenges center on carbon and nitrogen recycling and the implications of using waste materials in conjunction with virgin nutrients for secondary cultures. The aim of this review is to provide a foundation for further understanding of nutrient recycling for microalgae cultivation. As such, we outline the current state of technology and practical challenges associated with nutrient recycling for heterotrophic microalgae on an industrial scale and give recommendations for future work. PMID:26572520

  1. Fuels from microalgae: Technology status, potential, and research requirements

    Energy Technology Data Exchange (ETDEWEB)

    Neenan, B.; Feinberg, D.; Hill, A.; McIntosh, R.; Terry, K.

    1986-08-01

    Although numerous options for the production of fuels from microalgae have been proposed, our analysis indicates that only two qualify for extensive development - gasoline and ester fuel. In developing the comparisons that support this conclusion, we have identified the major areas of microalgae production and processing that require extensive development. Technology success requires developing and testing processes that fully utilize the polar and nonpolar lipids produced by microalgae. Process designs used in these analyses were derived from fragmented, preliminary laboratory data. These results must be substantiated and integrated processes proposed, tested, and refined to be able to evaluate the commercial feasibility from microalgae. The production of algal feedstocks for processing to gasoline or ester fuel requires algae of high productivity and high lipid content that efficiently utilize saline waters. Species screening and development suggest that algae can achieve required standards taken individually, but algae that can meet the integrated requirements still elude researchers. Effective development of fuels from microalgae technology requires that R and D be directed toward meeting the integrated standards set out in the analysis. As technology analysts, it is inappropriate for us to dictate how the R and D effort should proceed to meet these standards. We end our role by noting that alternative approaches to meeting the feasibility targets have been identified, and it is now the task of program managers and scientists to choose the appropriate approach to assure the greatest likelihood of realizing a commercially viable technology. 70 refs., 39 figs., 35 tabs.

  2. Low-cost harvesting of microalgae biomass from water

    Directory of Open Access Journals (Sweden)

    Bejor, E.S.

    2013-03-01

    Full Text Available Microalgae harvesting is known to be a major problem in the water industry. This is attributed to the minute nature of the algae cells and the often low concentration of the species in water and wastewater. While various chemical and mechanical harvesting techniques have been developed for algae harvesting, their application have been limited by prohibitive costs. There is also the disadvantage of not utilising the harvested microalgae as feedstock when it has accumulated significant amounts of chemicals (coagulants employed during the harvesting operation. This work investigates the low cost harvesting of microalgae biomass from water using physical (non-chemical method. Four fabric filters: stretch-cotton, polyester-linen, satin-polyester and silk were investigated to determine their microalgae harvesting efficiencies using filtration method on three algae communities with cell size of 2- 20 µm. For the three algae communities investigated, stretch-cotton filter showed a harvesting efficiency of 66- 93%, followed by polyester-linen (54- 90%, while satin-polyester and silk fabrics achieved harvesting efficiencies of 43- 71% and 27- 75% respectively. The research revealed that for wastewater generation of 1500m3/day and algae concentration of 200mg/l, microalgae harvesting cost per sq. meter per kg of algae per cubic meter would be ≤ £0.15 using stretch cotton filter

  3. Applications of microfluidics in microalgae biotechnology: A review.

    Science.gov (United States)

    Juang, Yi-Je; Chang, Jo-Shu

    2016-03-01

    Microalgae have been one of the important sources for biofuel production owing to their competitive advantages such as no need to tap into the global food supply chain, higher energy density, and absorbing carbon dioxide to mitigate global warming. One of the key factors to ensure successful biofuel production is that it requires not only bioprospecting of the microalgae with high lipid content, high growth rate and tolerance to environmental parameters but also on-site monitoring of the cultivation process and optimization of the culturing conditions. However, as the conventional techniques usually involve in complicated procedures, or are time-consuming or labor intensive, microfluidics technology offers an attractive alternative to resolve these issues. In this review, applications of microfluidics to bioprospecting in microalgae biotechnology were discussed such as cell identification, cell sorting/screening, cell culturing and cell disruption. In addition, utilization of microalgae in micro-sized fuel cells and microfluidic platforms for biosensing was addressed. This review reports the recent studies and offers a look into how microfluidics is exploited to tackle the issues encountered in the microalgae biotechnology. PMID:26807667

  4. Extracellular Metabolites from Industrial Microalgae and Their Biotechnological Potential

    Directory of Open Access Journals (Sweden)

    Lu Liu

    2016-10-01

    Full Text Available Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that might play an important role in biofuel development and environmental protection. Almost all current products of industrial microalgae are derived from their biomass; however, large amounts of spent cell-free media are available from mass cultivation that is mostly unexploited. In this contribution we discuss that these media, which may contain a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously, the extracellular metabolites from industrial microalgae have long been neglected in the development of production methods for valuable metabolites. With the advances in the last ten years, more and more structures and properties from extracellular metabolites have been identified, and the potential utilization over wide fields is attracting attention. Some of these extracellular metabolites can be potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this review is to provide an overview of the known extracellular metabolites from industrial microalgae which might be of commercial interest. The attention mainly focuses on the reports of extracellular bioactive metabolites and their potential application in biotechnology.

  5. Extracellular Metabolites from Industrial Microalgae and Their Biotechnological Potential

    Science.gov (United States)

    Liu, Lu; Pohnert, Georg; Wei, Dong

    2016-01-01

    Industrial microalgae, as a big family of promising producers of renewable biomass feedstock, have been commercially exploited for functional food, living feed and feed additives, high-value chemicals in nutraceuticals, cosmeceuticals, and chemical reagents. Recently, microalgae have also been considered as a group that might play an important role in biofuel development and environmental protection. Almost all current products of industrial microalgae are derived from their biomass; however, large amounts of spent cell-free media are available from mass cultivation that is mostly unexploited. In this contribution we discuss that these media, which may contain a remarkable diversity of bioactive substances are worthy to be recovered for further use. Obviously, the extracellular metabolites from industrial microalgae have long been neglected in the development of production methods for valuable metabolites. With the advances in the last ten years, more and more structures and properties from extracellular metabolites have been identified, and the potential utilization over wide fields is attracting attention. Some of these extracellular metabolites can be potentially used as drugs, antioxidants, growth regulators or metal chelators. The purpose of this review is to provide an overview of the known extracellular metabolites from industrial microalgae which might be of commercial interest. The attention mainly focuses on the reports of extracellular bioactive metabolites and their potential application in biotechnology. PMID:27775594

  6. Biodiesel renovável derivado de microalgas: avanços e perspectivas tecnológicas

    OpenAIRE

    Claudio M. P. Pereira; Cristiane B. Hobuss; Juliana Villela Maciel; Lizângela R. Ferreira; Francisco B. Del Pino; Márcia F. Mesko; Eduardo Jacob-Lopes; Pio Colepicolo Neto

    2012-01-01

    Microalgae are a promising source of raw material for biodiesel production. This review discusses the latest developments related to the application of microalgae biomass for biodiesel production. Characterization of fatty acid of microalgae and comparisons with other sources of raw materials and processes are presented. Furthermore, technological perspectives and approaches for growing microalgae in photobioreactors, microalgal oil extraction techniques, and procedures for synthesizing biodi...

  7. Growth of microalgae in autotrophic stationary systems

    Directory of Open Access Journals (Sweden)

    Paulo Cunha

    2008-06-01

    Full Text Available In this paper we evaluate the growth of nine marine microalgae species (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira fluviatilis and Isochrysis sp. and one freshwater species (Chlorella vulgaris under stationary autotrophy conditions, using erlenmeyers fl asks with 800mL of culture medium exposed to constant light intensities providing a photon flux density of about 150μmol.m-2.s-1 and 25±2oC temperature and constant air flow. The experiment was carried out in a controlled environment considering a block delineating randomized over time with three replicates. The Nannochloropsis oculata showed the highest value of maximum cellular density, but with a longer period of time and a lower growth rate. This was probably due to its tiny cell size, demanding a large number of cells per volume to attain its optimum conditions for light, nutrients, water and atmospheric carbon dioxide. In addition, in spite of showing one of the lowest values of maximum cellular density, Thalassiosira fluviatilis was the species that reached its maximum in a short period of time at the highest growth rate. Chlorella vulgaris was the only freshwater species tested and it showed the poorest performance for all the variables analyzed in the current study.

  8. Microalgae Culture Collection, 1985-1986

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The SERI Microalgae Culture Collection was established in support of the US Department of Energy's Biofuels Program to provide a repository for strains identified or developed for mass culture biomass production and to make these strains readily available to the research community. The strains in the collection have been selected for their potential in biomass fuel applications, and many produce significant quantities of cellular storage lipids. The Culture Collection Catalog lists 20 strains of ten species. Many have been tested in outdoor mass culture systems, and several have demonstrated excellent performance as biomass producers, with yields of up to 40 grams of organic matter per square meter per day. The majority of strains added to the collection this year have been isolated from inland saline waters, although marine species are included as well. We believe that the strains in this collection can provide a source of extremely useful organisms, both for laboratory experimentation and for mass culture research. 98 refs., 31 figs., 52 tabs.

  9. Metallomic study of microalgae as functional food

    International Nuclear Information System (INIS)

    Complete text of publication follows. Functional food is becoming an important issue in the last decade providing additional physiological benefits to basic nutritional stuff. Some essential elements such as selenium and iodine are biotechnologically incorporated to foods using element-enriched micro algae biomass (mainly, Chlamydomonas reinhardtii, Spirulina platensis, and Chlorella vulgaris). An important question is the chemical forms in which the heteroelement (Se, I) is involved, because metabolites represent a set of active biomolecules with potential health effects (metabolomics). Therefore, the design of suitable analytical approaches based on the use of these heteroelements as biomolecule tag, with ICP-MS coupled to multidimensional chromatographic techniques and assisted by 2D electrophoresis constitutes a powerful tool for this purpose. In this work, the microalgae Chlorella vulgaris has been used for selenium enrichment with a biotechnologic production platform. Selenium-containing metabolites were extracted from the biomass and characterized with a metallomics approach which involves selenium SEC-ICPMS profiling and latter purification of SEC-ICP-MS fractions by HPLC-ICPMS chromatography. Purified Se-biomolecules where characterized by tandem mass spectrometry. 2D electrophoresis was used in parallel to monitor the purification process.

  10. Microalgae as bioreactors for bioplastic production

    Directory of Open Access Journals (Sweden)

    Steinbüchel Alexander

    2011-10-01

    Full Text Available Abstract Background Poly-3-hydroxybutyrate (PHB is a polyester with thermoplastic properties that is naturally occurring and produced by such bacteria as Ralstonia eutropha H16 and Bacillus megaterium. In contrast to currently utilized plastics and most synthetic polymers, PHB is biodegradable, and its production is not dependent on fossil resources making this bioplastic interesting for various industrial applications. Results In this study, we report on introducing the bacterial PHB pathway of R. eutropha H16 into the diatom Phaeodactylum tricornutum, thereby demonstrating for the first time that PHB production is feasible in a microalgal system. Expression of the bacterial enzymes was sufficient to result in PHB levels of up to 10.6% of algal dry weight. The bioplastic accumulated in granule-like structures in the cytosol of the cells, as shown by light and electron microscopy. Conclusions Our studies demonstrate the great potential of microalgae like the diatom P. tricornutum to serve as solar-powered expression factories and reveal great advantages compared to plant based production systems.

  11. Microalgae culture collection, 1986-1987

    Energy Technology Data Exchange (ETDEWEB)

    Barclay, W.; Johansen, J.; Chelf, P.; Nagle, N.; Roessler, P.; Lemke, P.

    1986-12-01

    The SERI Microalgae Culture Collection provides a repository for strains identified or developed for mass culture biomass production and makes these strains readily available to the research community. The strains in the collection have been selected for their potential in biomass fuel applications, and many produce significant quantities of cellular storage lipids. All of the newly added strains have been recently isolated by SERI and its subcontractors in organized screening programs. Many have been tested in outdoor mass culture systems, and several have demonstrated excellent performance as biomass producers. The strains added to the collection this year have been isolated from inland saline waters and marine waters. We believe that the strains in this collection can provide a source of extremely useful organisms, both for laboratory experimentation and for mass culture research. Most of the strains are currently nonaxenic. Again this year, cultures will be shipped free of charge to interested researchers. An important function of the culture collection catalog, in addition to listing the available strains, is to provide culture and performance data for each of the organisms. By collecting a summary of the requirements and characteristics of these organisms, we hope to allow requestors of cultures to begin productive research with a minimum of preliminary work on culture techniques.

  12. Bioactivity and Applications of Sulphated Polysaccharides from Marine Microalgae

    Directory of Open Access Journals (Sweden)

    Rui Manuel Santos Costa de Morais

    2013-01-01

    Full Text Available Marine microalgae have been used for a long time as food for humans, such as Arthrospira (formerly, Spirulina, and for animals in aquaculture. The biomass of these microalgae and the compounds they produce have been shown to possess several biological applications with numerous health benefits. The present review puts up-to-date the research on the biological activities and applications of polysaccharides, active biocompounds synthesized by marine unicellular algae, which are, most of the times, released into the surrounding medium (exo- or extracellular polysaccharides, EPS. It goes through the most studied activities of sulphated polysaccharides (sPS or their derivatives, but also highlights lesser known applications as hypolipidaemic or hypoglycaemic, or as biolubricant agents and drag-reducers. Therefore, the great potentials of sPS from marine microalgae to be used as nutraceuticals, therapeutic agents, cosmetics, or in other areas, such as engineering, are approached in this review.

  13. Sustainability and economic evaluation of microalgae grown in brewery wastewater.

    Science.gov (United States)

    Mata, Teresa M; Mendes, Adélio M; Caetano, Nídia S; Martins, António A

    2014-09-01

    This article evaluates the sustainability and economic potential of microalgae grown in brewery wastewater for biodiesel and biomass production. Three sustainability and two economic indicators were considered in the evaluation within a life cycle perspective. For the production system the most efficient process units were selected. Results show that harvesting and oil separation are the main process bottlenecks. Microalgae with higher lipid content and productivity are desirable for biodiesel production, although comparable to other biofuel's feedstock concerning sustainability. However, improvements are still needed to reach the performance level of fossil diesel. Profitability reaches a limit for larger cultivation areas, being higher when extracted biomass is sold together with microalgae oil, in which case the influence of lipid content and areal productivity is smaller. The values of oil and/or biomass prices calculated to ensure that the process is economically sound are still very high compared with other fuel options, especially biodiesel.

  14. Integrated Microalgae Analysis Photobioreactor for Rapid Strain Selection.

    Science.gov (United States)

    Hong, SoonGweon; Song, Minsun; Kim, Sungjun; Bang, Doyeon; Kang, Taewook; Choi, Inhee; Lee, Luke P

    2016-06-28

    Algal photosynthesis is considered to be a sustainable, alternative, and renewable solution to generating green energy. For high-productivity algaculture in diverse local environments, a high-throughput screening method is needed to select algal strains from naturally available or genetically engineered strains. Herein, we present an integrated plasmonic photobioreactor for rapid, high-throughput screening of microalgae. Our 3D nanoplasmonic optical cavity-based photobioreactor permits the amplification of a selective wavelength favorable to photosynthesis in the cavity. The hemispheric plasmonic cavity allows intercellular interaction to be promoted in the optically favorable milieu and also permits effective visual examination of algal growth. Using Chlamydomonas reinhardtii, we demonstrated a 2-fold enhanced growth rate and a 1.5-fold lipid production rate with no distinctive lag phase. By facilitating growth and biomass conversion rates, the integrated microalgae analysis platform will serve as rapid microalgae screening platforms for biofuel applications. PMID:27227421

  15. Treatment of drainage solution from hydroponic greenhouse production with microalgae.

    Science.gov (United States)

    Hultberg, Malin; Carlsson, Anders S; Gustafsson, Susanne

    2013-05-01

    This study investigated treatment of the drainage solution from greenhouse production with microalgae, through inoculation with Chlorella vulgaris or through growth of the indigenous microalgal community. A significant reduction in nitrogen, between 34.7 and 73.7 mg L(-1), and particularly in phosphorus concentration, between 15.4 and 15.9 mg L(-1), was observed in drainage solution collected from commercial greenhouse production. The large reduction in nutrients was achieved through growth of the indigenous microalgal community i.e., without pre-treatment of the drainage solution or inoculation with the fast growing green microalgae C. vulgaris. Analysis of the fatty acid composition of the algal biomass revealed that compared with a standard growth medium for green algae, the drainage solution was inferior for lipid production. Despite the biorefinery concept being less promising, microalgae-based treatment of drainage solution from greenhouse production is still of interest considering the urgent need for phosphorus recycling.

  16. Cultivation Of Microalgae (Chlorella vulgaris For Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Blinová Lenka

    2015-06-01

    Full Text Available Production of biofuel from renewable sources is considered to be one of the most sustainable alternatives to petroleum sourced fuels. Biofuels are also viable means of environmental and economic sustainability. Biofuels are divided into four generations, depending on the type of biomass used for biofuels production. At present, microalgae are presented as an ideal third generation biofuel feedstock because of their rapid growth rate. They also do not compete with food or feed crops, and can be produced on non-arable land. Cultivation conditions (temperature, pH, light, nutrient quantity and quality, salinity, aerating are the major factors that influence photosynthesis activity and behaviour of the microalgae growth rate. In this paper, we present an overview about the effect of cultivation conditions on microalgae growth.

  17. Cultivation Of Microalgae (Chlorella vulgaris) For Biodiesel Production

    Science.gov (United States)

    Blinová, Lenka; Bartošová, Alica; Gerulová, Kristína

    2015-06-01

    Production of biofuel from renewable sources is considered to be one of the most sustainable alternatives to petroleum sourced fuels. Biofuels are also viable means of environmental and economic sustainability. Biofuels are divided into four generations, depending on the type of biomass used for biofuels production. At present, microalgae are presented as an ideal third generation biofuel feedstock because of their rapid growth rate. They also do not compete with food or feed crops, and can be produced on non-arable land. Cultivation conditions (temperature, pH, light, nutrient quantity and quality, salinity, aerating) are the major factors that influence photosynthesis activity and behaviour of the microalgae growth rate. In this paper, we present an overview about the effect of cultivation conditions on microalgae growth.

  18. Microalgae Isolation and Selection for Prospective Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Peer M. Schenk

    2012-06-01

    Full Text Available Biodiesel production from microalgae is being widely developed at different scales as a potential source of renewable energy with both economic and environmental benefits. Although many microalgae species have been identified and isolated for lipid production, there is currently no consensus as to which species provide the highest productivity. Different species are expected to function best at different aquatic, geographical and climatic conditions. In addition, other value-added products are now being considered for commercial production which necessitates the selection of the most capable algae strains suitable for multiple-product algae biorefineries. Here we present and review practical issues of several simple and robust methods for microalgae isolation and selection for traits that maybe most relevant for commercial biodiesel production. A combination of conventional and modern techniques is likely to be the most efficient route from isolation to large-scale cultivation.

  19. Toxic effects of oil and dispersant on marine microalgae.

    Science.gov (United States)

    Garr, Amber L; Laramore, Susan; Krebs, William

    2014-12-01

    To better understand the potential impacts of the deepwater horizon oil spill on lower trophic level food sources, a series of toxicological laboratory experiments were conducted with two microalgae species. The acute toxicity of oil (tar mat and MC252 crude oil), dispersant (Corexit 9500A), and dispersed oil on growth inhibition (IC50) and motility of Isochrysis galbana and Chaetoceros sp. were determined. There was no impact on cell division (growth) for microalgae exposed to both oil types and mean motility of I. galbana never dropped below 79 %. However, the addition of dispersant inhibited cell division and motility within 24 h, with Chaetoceros sp. being more susceptible to sublethal effects than I. galbana. These results highlight microalgae sensitivity to the use of dispersants in bioremediation processes, which may be a concern for long-term impacts on fisheries recruitment. PMID:25283369

  20. Correlation study of microalgae carbonation in membrane integrated photobioreactor

    Science.gov (United States)

    Suali, E.; Sarbatly, R.; Shaleh, S. R. M.; Lahin, F. A.; Anisuzzaman, S. M.

    2016-06-01

    Microalgae ability to utilise CO2 higher compared to terrestrial plant making it suitable for biomass production and as CO2 utiliser. This could be one of many ways to preserve a safer and healthier environment with less air pollutant. For study purposes, CO2 usually transported to microalgae culture broth with the aid of membrane technology to prevent formation of large bubble and to accelerate the carbonation of microalgal media. However, membrane susceptible to accumulation of CO2, which can cause extreme acidic to microalgal media. This prevents microalgae to assimilate CO2. Thus, this study proposes correlations to prevent the extreme acidic: which represents the relationship of: (1) CO2 inlet and accumulation, (2) CO2 inlet and CO2 at the membrane-liquid interphase and (3) CO2 inlet and CO2 solubility in the media. The correlations were successfully validated with a deviation of less than 20% compared to the theoretical value.

  1. Microalgae as a Source for VLC-PUFA Production.

    Science.gov (United States)

    Khozin-Goldberg, Inna; Leu, Stefan; Boussiba, Sammy

    2016-01-01

    Microalgae present a huge and still insufficiently tapped resource of very long-chain omega-3 and omega-6 polyunsaturated fatty acids (VLC-PUFA) for human nutrition and medicinal applications. This chapter describes the diversity of unicellular eukaryotic microalgae in respect to VLC-PUFA biosynthesis. Then, we outline the major biosynthetic pathways mediating the formation of VLC-PUFA by sequential desaturation and elongation of C18-PUFA acyl groups. We address the aspects of spatial localization of those pathways and elaborate on the role for VLC-PUFA in microalgal cells. Recent progress in microalgal genetic transformation and molecular engineering has opened the way to increased production efficiencies for VLC-PUFA. The perspectives of photobiotechnology and metabolic engineering of microalgae for altered or enhanced VLC-PUFA production are also discussed. PMID:27023247

  2. Effect of the temperature on the sorption of cadmium in natural clinoptilolite from the State of Chihuahua; Efecto de la temperatura sobre la sorcion de cadmio en clinoptilolita natural del Estado de Chihuahua

    Energy Technology Data Exchange (ETDEWEB)

    Arambula V, V

    2004-07-01

    The investigation works related with the removal of cadmium of aqueous solutions, they make emphasis in a great number of materials that were used for this end, as well as in the parameters that influence, such as the temperature and the pH. In this work it was investigated the effect of the temperature on the removal of cadmium, using a zeolitic mineral native of the State of Chihuahua for they were determined it kinetic parameters, those diffusivity coefficients and the retention mechanisms (adsorption or ion exchange) involved. The clinoptilolite samples were characterized by means of scanning electron microscopy in high vacuum (MEB), elementary microanalysis (EDS) and X-ray diffraction (XRD). The experimental part consisted on putting in contact solutions of cadmium with the mineral, varying the temperature, the time of contact or the concentration; the quantification of sodium and cadmium in the liquid phase was carried out by means of atomic absorption spectroscopy (EAA). It was determined the time of equilibrium for the removal process. The temperature and the concentration influence on the process of sorption of cadmium in the zeolitic mineral (kinetics and isotherms). The kinetic model that describes better the sorption process of cadmium in the clinoptilolite was the pseudo-2 order. The apparent coefficient of diffusivity presented a greater value conforms to increment the temperature. The results of the isotherm of adsorption of cadmium presented a better adjustment to the Freundlich model. The quantity of cadmium retained by the mineral it was greater than the quantity of sodium found in the solution after the contact between the solution of cadmium and the zeolitic mineral and in accordance with the obtained separation factors, the natural zeolite shows a greater affinity for the cadmium that for the sodium ({alpha} > 1). (Author)

  3. Advances and perspectives in using microalgae to produce biodiesel

    International Nuclear Information System (INIS)

    Carbon-neutral renewable liquid biofuels are needed to displace petroleum-derived transport fuels in the near future - which contribute to global warming and are of a limited availability. A promising alternative is conveyed by microalgae, the oil content of which may exceed 80% (w/wDW) - as compared with 5% of the best agricultural oil crops. However, current implementation of microalga-based systems has been economically constrained by their still poor volumetric efficiencies - which lead to excessively high costs, as compared with petrofuel prices. Technological improvements of such processes are thus critical - and this will require a multiple approach, both on the biocatalyst and bioreactor levels. Several bottlenecks indeed exist at present that preclude the full industrial exploitation of microalgal cells: the number of species that have been subjected to successful genetic transformation is scarce, which hampers a global understanding (and thus a rational design) of novel blue-biotechnological processes; the mechanisms that control regulation of gene expression are not fully elucidated, as required before effective bioprocesses based on microalgae can be scaled-up; and new molecular biology tools are needed to standardize genetic modifications in microalgae - including efficient nuclear transformation, availability of promoter or selectable marker genes, and stable expression of transgenes. On the other hand, a number of pending technological issues are also present: the relatively low microalga intrinsic lipid productivity; the maximum cell concentration attainable; the efficiency of harvest and sequential recovery of bulk lipids; and the possibility of by-product upgrade. This review briefly covers the state of the art regarding microalgae toward production of biofuels, both from the point of view of the microalgal cell itself and of the supporting bioreactor; and discusses, in a critical manner, current limitations and promising perspectives in this

  4. Biogas Production From Cassava Starch Effluent Using Microalgae As Biostabilisator

    Directory of Open Access Journals (Sweden)

    B. Budiyono

    2011-07-01

    Full Text Available The rapid growing of Indonesian population is emerging several critical national issues i.e. energy, food, environmental, water, transportation, as well as law and human right. As an agricultural country, Indonesia has abundant of biomass wastes such as agricultural wastes include the cassava starch wastes. The problem is that the effluent from cassava starch factories is released directly into the river before properly treatment. It has been a great source of pollution and has caused environmental problems to the nearby rural population. The possible alternative to solve the problem is by converting waste to energy biogas in the biodigester. The main problem of the biogas production of cassava starch effluent is acid forming-bacteria quickly produced acid resulting significantly in declining pH below the neutral pH and diminishing growth of methane bacteria. Hence, the only one of the method to cover this problem is by adding microalgae as biostabilisator of pH. Microalgae can also be used as purifier agent to absorb CO2.The general objective of this research project was to develop an integrated process of biogas production and purification from cassava starch effluent by using biostabilisator agent microalgae. This study has been focused on the used of urea, ruminant, yeast, microalgae, the treatment of gelled and ungelled feed for biogas production, pH control during biogas production using buffer Na2CO3, and feeding management in the semi-continuous process of biogas production. The result can be concluded as follows: i The biogas production increased after cassava starch effluent and yeast was added, ii Biogas production with microalgae and cassava starch effluent, yeast, ruminant bacteria, and urea were 726.43 ml/g total solid, iii Biogas production without  microalgae was 189 ml/g total solid.

  5. Microalgae as a raw material for biofuels production.

    Science.gov (United States)

    Gouveia, Luisa; Oliveira, Ana Cristina

    2009-02-01

    Biofuels demand is unquestionable in order to reduce gaseous emissions (fossil CO(2), nitrogen and sulfur oxides) and their purported greenhouse, climatic changes and global warming effects, to face the frequent oil supply crises, as a way to help non-fossil fuel producer countries to reduce energy dependence, contributing to security of supply, promoting environmental sustainability and meeting the EU target of at least of 10% biofuels in the transport sector by 2020. Biodiesel is usually produced from oleaginous crops, such as rapeseed, soybean, sunflower and palm. However, the use of microalgae can be a suitable alternative feedstock for next generation biofuels because certain species contain high amounts of oil, which could be extracted, processed and refined into transportation fuels, using currently available technology; they have fast growth rate, permit the use of non-arable land and non-potable water, use far less water and do not displace food crops cultures; their production is not seasonal and they can be harvested daily. The screening of microalgae (Chlorella vulgaris, Spirulina maxima, Nannochloropsis sp., Neochloris oleabundans, Scenedesmus obliquus and Dunaliella tertiolecta) was done in order to choose the best one(s), in terms of quantity and quality as oil source for biofuel production. Neochloris oleabundans (fresh water microalga) and Nannochloropsis sp. (marine microalga) proved to be suitable as raw materials for biofuel production, due to their high oil content (29.0 and 28.7%, respectively). Both microalgae, when grown under nitrogen shortage, show a great increase (approximately 50%) in oil quantity. If the purpose is to produce biodiesel only from one species, Scenedesmus obliquus presents the most adequate fatty acid profile, namely in terms of linolenic and other polyunsaturated fatty acids. However, the microalgae Neochloris oleabundans, Nannochloropsis sp. and Dunaliella tertiolecta can also be used if associated with other

  6. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    Science.gov (United States)

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency.

  7. Batch anaerobic co-digestion of waste activated sludge and microalgae (Chlorella sorokiniana) at mesophilic temperature.

    Science.gov (United States)

    Beltrán, Carolina; Jeison, David; Fermoso, Fernando G; Borja, Rafael

    2016-08-23

    The microalgae Chlorella sorokiniana are used as co-substrate for waste activated sludge (WAS) anaerobic digestion. The specific objective of this research was to evaluate the feasibility of improving methane production from anaerobic digestion of WAS in co-digestion with this microalga, based on an optimized mixture percentage. Thus, the anaerobic co-digestion of both substrates aims to overcome the drawbacks of the anaerobic digestion of single WAS, simultaneously improving its management. Different co-digestion mixtures (0% WAS-100% microalgae; 25% WAS-75% microalgae; 50% WAS-50% microalgae; 75% WAS-25% microalgae; 100% WAS-0% microalgae) were studied. The highest methane yield (442 mL CH4/g VS) was obtained for the mixture with 75% WAS and 25% microalgae. This value was 22% and 39% higher than that obtained in the anaerobic digestion of the sole substrates WAS and microalgae, respectively, as well as 16% and 25% higher than those obtained for the co-digestion mixtures with 25% WAS and 75% microalgae and 50% WAS and 50% microalgae, respectively. The kinetic constant of the process increased 42%, 42% and 12%, respectively, for the mixtures with 25%, 50% and 75% of WAS compared to the substrate without WAS. Anaerobic digestion of WAS, together with C. sorokiniana, has been clearly improved by ensuring its viability, suitability and efficiency. PMID:27230742

  8. Biofuel production from microalgae as feedstock: current status and potential.

    Science.gov (United States)

    Han, Song-Fang; Jin, Wen-Biao; Tu, Ren-Jie; Wu, Wei-Min

    2015-06-01

    Algal biofuel has become an attractive alternative of petroleum-based fuels in the past decade. Microalgae have been proposed as a feedstock to produce biodiesel, since they are capable of mitigating CO2 emission and accumulating lipids with high productivity. This article is an overview of the updated status of biofuels, especially biodiesel production from microalgae including fundamental research, culture selection and engineering process development; it summarizes research on mathematical and life cycle modeling on algae growth and biomass production; and it updates global efforts of research and development and commercialization attempts. The major challenges are also discussed.

  9. Antioxidative properties of some phototropic microalgae grown in waste water

    OpenAIRE

    Safafar, Hamed; Jacobsen, Charlotte; Møller, Peter

    2014-01-01

    Microalgae can be a new source of oil and protein in the aquaculture industry while their potential as natural sources of antioxidants has gained recent attention. Not only the fatty acid and amino acid composition but also the antioxidative properties of the micro algae biomass is important when selecting the species to be used for fish feed. The present study is part of a project which aims at developing new processing technologies, so that microalgae-biomass can be used as an alternative v...

  10. A quick colorimetric method for total lipid quantification in microalgae.

    Science.gov (United States)

    Byreddy, Avinesh R; Gupta, Adarsha; Barrow, Colin J; Puri, Munish

    2016-06-01

    Discovering microalgae with high lipid productivity are among the key milestones for achieving sustainable biodiesel production. Current methods of lipid quantification are time intensive and costly. A rapid colorimetric method based on sulfo-phospho-vanillin (SPV) reaction was developed for the quantification of microbial lipids to facilitate screening for lipid producing microalgae. This method was successfully tested on marine thraustochytrid strains and vegetable oils. The colorimetric method results correlated well with gravimetric method estimates. The new method was less time consuming than gravimetric analysis and is quantitative for lipid determination, even in the presence of carbohydrates, proteins and glycerol. PMID:27050419

  11. Efficient recovery of uranium using genetically improved microalgae

    International Nuclear Information System (INIS)

    We propose an alternative process for the efficient recovery of dissolved uranium based on genetically improved microalgae. We isolate Chlamydomonas cf. fonticola from a pond extremely contaminated by uranium (∼ 25 ppm) from ENUSA U-mine, Saelices (Salamanca, Spain). After a process of genetic improvement we obtained a strain capable to recover 115 mg of U per g of dry weight, by mean of bio-adsorption on the cell wall (mostly) and intra-cytoplasm bioaccumulation. Such a genetically improved microalgae resist extremes of acidity and pollution, but even its dead biomass is still able to recover a large amount of uranium. (Author)

  12. Microalgae: An alternative as sustainable source of biofuels?

    International Nuclear Information System (INIS)

    In recent decades, the world has been confronted with an energy crisis associated with irreversible depletion of traditional sources of fossil fuels, coupled with atmospheric accumulation of greenhouse gases that cause global warming. The urgent need to replace traditional fuels led to emergence of biodiesel and biohydrogen as interesting alternatives, both of which can be obtained via microalga-mediated routes. Microalgae are ubiquitous eukaryotic microorganisms, characterized by a remarkable metabolic plasticity. Their oil productivities are much higher than those of higher terrestrial plants, and they do not require high quality agricultural land. Microalgae may indeed be cultivated in brackish and wastewaters that provide suitable nutrients (e.g. NH4+,NO3−andPO43−), at the expense of only sunlight and atmospheric CO2. On the other hand, metabolic engineering permits release of molecular hydrogen also via photosynthetic routes, which will easily be converted to electricity in fuel cells or mechanical power in explosion engines, with only water vapor as exhaust product in both cases. However, large-scale implementation of microalga-based systems to manufacture biodiesel and biohydrogen has been economically constrained by their still poor volumetric efficiencies, which imply excessively high costs when compared with current petrofuel prices. Technological improvements are accordingly critical, both on the biocatalyst and the bioreactor levels. The current bottlenecks that have apparently precluded full industrial exploitation of microalgae cells are critically discussed here, viz. those derived from the scarce knowledge on the mechanisms that control regulation of gene expression, the reduced number of species subjected to successful genetic transformation, the relatively low cell density attainable, the poor efficiency in harvesting, and the difficulties in light capture and use. Therefore, this paper provides an overview of the feasibility of microalgae for

  13. Biomass and biofuels from microalgae advances in engineering and biology

    CERN Document Server

    Moheimani, Navid Reza; de Boer, Karne; Bahri, Parisa

    2015-01-01

    This comprehensive book details the most recent advances in the microalgae biological sciences and engineering technologies for biomass and biofuel production in order to meet the ongoing need for new and affordable sources of food, chemicals and energy for future generations. The chapters explore new microalgae cultivation techniques, including solid (biofilm) systems, and heterotrophic production methods, while also critically investigating topics such as combining wastewater as a source of nutrients, the effect of CO2 on growth, and converting biomass to methane through anaerobi

  14. Potency of Microalgae as Biodiesel Source in Indonesia

    Directory of Open Access Journals (Sweden)

    H Hadiyanto

    2012-04-01

    Full Text Available Within 20 years, Indonesia should find another energy alternative to substitutecurrent fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17%of our energy mix program. Even though, most of the area in Indonesia is covered by sea, howeverthe utilization of microalgae as biofuel production is still limited. The biodiesel from currentsources (Jatropha, palm oil, and sorghum is still not able to cover all the needs if the fossil oilcannot be explored anymore. In this paper, the potency of microalgae in Indonesia was analysed asthe new potential of energy (biodiesel sources.

  15. Life-cycle assessment of microalgae biodiesel: a review

    OpenAIRE

    Figueiredo, Filipa; Garcia, Rita; Gonçalves, Margarida S.; Castanheira, Érica; Malça, João; de Oliveira, A C; Matos, Cristina T.; Freire, Fausto

    2015-01-01

    Microalgae are an attractive way to produce biofuels due to the ability to accumulate lipids and very high photosynthetic yields. This article presents a review of life-cycle assessment studies of microalgae biodiesel production, including an analysis of modeling choices and assumptions. A high variation in GHG emissions (between -0.75 and 2.9 kg CO2eq MJ-1) was found and the main causes were investigated, namely modeling choices (e.g. the approach used to deal with multifunctionality), and a...

  16. Potency of Microalgae as Biodiesel Source in Indonesia

    Directory of Open Access Journals (Sweden)

    H Hadiyanto

    2012-02-01

    Full Text Available Within 20 years, Indonesia should find another energy alternative to substitute current fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17% of our energy mix program. Even though, most of the area in Indonesia is covered by sea, however the utilization of microalgae as biofuel production is still limited. The biodiesel from current sources (Jatropha, palm oil, and sorghum is still not able to cover all the needs if the fossil oil cannot be explored anymore. In this paper, the potency of microalgae in Indonesia was analysed as the new potential of energy (biodiesel sources.

  17. Effects of bacterial communities on biofuel-producing microalgae: stimulation, inhibition and harvesting.

    Science.gov (United States)

    Wang, Hui; Hill, Russell T; Zheng, Tianling; Hu, Xiaoke; Wang, Bin

    2016-01-01

    Despite the great interest in microalgae as a potential source of biofuel to substitute for fossil fuels, little information is available on the effects of bacterial symbionts in mass algal cultivation systems. The bacterial communities associated with microalgae are a crucial factor in the process of microalgal biomass and lipid production and may stimulate or inhibit growth of biofuel-producing microalgae. In addition, we discuss here the potential use of bacteria to harvest biofuel-producing microalgae. We propose that aggregation of microalgae by bacteria to achieve >90% reductions in volume followed by centrifugation could be an economic approach for harvesting of biofuel-producing microalgae. Our aims in this review are to promote understanding of the effects of bacterial communities on microalgae and draw attention to the importance of this topic in the microalgal biofuel field.

  18. Comparison of direct and indirect pyrolysis of micro-algae Isochrysis.

    Science.gov (United States)

    Wang, Xin; Zhao, Bingwei; Tang, Xiaohan; Yang, Xiaoyi

    2015-03-01

    Yield and composition of pyrolysis oil in direct and indirect pyrolysis process were investigated which indicated that pyrolysis of defatted microalgae provided a potential way to convert protein and carbohydrate to biofuels. Defatted microalgae pyrolysis with lipid extraction has higher total oil yield than only microalgae direct pyrolysis. There was an increase for N-heterocyclic compounds and phenols and a decrease for hydrocarbons in defatted microalgae pyrolysis oil. There is an apparent decrease from C12 to C16 and nearly no carbon distribution from C17 to C22 for defatted microalgae pyrolysis. Based on composition of pyrolysis feedstock, pyrolysis oil yields were simulated by Compounds Biofuel Model and their accuracy was less than ±4.4%. Considering total oil yield and characteristics, microalgae pyrolysis after lipid extraction process is a promising way for microalgae utilization.

  19. Microalgae as a sustainable energy source for biodiesel production: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, A.L.; Yasin, N.H. Mat; Derek, C.J.C.; Lim, J.K. [School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Seberang Perai Selatan, Pulau Pinang (Malaysia)

    2011-01-15

    Of the three generations of biodiesel feedstocks described in this paper, food crops, non-food crops and microalgae-derived biodiesel, it was found that the third generation, microalgae, is the only source that can be sustainably developed in the future. Microalgae can be converted directly into energy, such as biodiesel, and therefore appear to be a promising source of renewable energy. This paper presents a comparison between the use of microalgae and palm oil as biodiesel feedstocks. It was found that microalgae are the more sustainable source of biodiesel in terms of food security and environmental impact compared to palm oil. The inefficiency and unsustainability of the use of food crops as a biodiesel source have increased interest in the development of microalgae species to be used as a renewable energy source. In this paper, the main advantages of using microalgae for biodiesel production are described in comparison with other available feedstocks, primarily palm oil. (author)

  20. Interaction of detritus with abundance of cyanobacteria and microalgae

    NARCIS (Netherlands)

    Gons, H.J.

    1995-01-01

    Detritus particles interact with phytoplankton growth through light attenuation and nutrient retention. A model is described for predicting abundance of cyanobacteria and microalgae in relation to the detritus dynamics in shallow lakes with varying phosphorus load. Steady-state P distribution among

  1. Ingestion of Brachionus plicatilis under different microalgae conditions

    Science.gov (United States)

    Zhou, Wenli; Tang, Xuexi; Qiao, Xiuting; Wang, You; Wang, Renjun; Feng, Lei

    2009-09-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  2. Ingestion of Brachionus plicatilis under different microalgae conditions

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wenli; TANG Xuexi; QIAO Xiuying; WANG You; WANG Renjun; FENG Lei

    2009-01-01

    The effects of four microalgae, Chlorella vulgaris, Platymonas helgolandicavar, Isochrysis galbana, and Nitzschia closterium on the grazing and filtering rates of the marine rotifer, Brachionus plicatilis, were evaluated under laboratory conditions. The grazing rates in separate cultures of the four microalga were as follows: C. vulgaris > P. helgolandicavar > I. galbana > N. closterium. However, the filtering rates occurred in the following order: P. helgolandicavar > N. closterium > C. vulgaris > I. galbana. A mixed diets experiment revealed that P. helgolandicavar was the preferred diet of B. plicatilis. In addition, the grazing rate of B. plicatilis increased gradually as the density of the microalgae increased, until concentrations of 2.5×106 cells mL-1 for C. vulgaris and 1.5×106 cells mL-1 for I. galbana were obtained. Furthermore, the filtering rate increased slightly when the density of the microalgae was low, after which it declined as the microalgal density increased. The grazing rates of B. plicatilis were as follows during the different growth phases: stationary phase > exponential phase > lag phase > decline phase. Additionally, the filtering rates during the growth phases were: exponential phase > lag phase > stationary phase > decline phase. The results of this study provide foundational information that can be used to explore the optimal culture conditions for rotifers and to promote the development of aquaculture.

  3. Potential of industrial biotechnology with cyanobacteria and eukaryotic microalgae

    NARCIS (Netherlands)

    Wijffels, R.H.; Kruse, O.; Hellingwerf, K.J.

    2013-01-01

    Both cyanobacteria and eukaryotic microalgae are promising organisms for sustainable production of bulk products such as food, feed, materials, chemicals and fuels. In this review we will summarize the potential and current biotechnological developments.Cyanobacteria are promising host organisms for

  4. A techno-economic analysis of biodiesel production from microalgae

    NARCIS (Netherlands)

    Olivieri, G.; Guida, T.; Salatino, P.; Marzocchella, A.

    2013-01-01

    The preliminary assessment of a cost-effective flow-sheet for the production of biodiesel from microalgae lipid fraction was carried out. The study was based on approximated cost-estimation methods integrated with the simulation software Aspen Plus (R). Several scenarios were investigated to compare

  5. Rapid biodiesel production using wet microalgae via microwave irradiation

    International Nuclear Information System (INIS)

    Highlights: • Lipid was directly extracted from wet microalgae using microwave irradiation. • The microwave irradiation and water bath-assisted solvent extraction are applied. • Cell walls are significantly disrupted under microwave irradiation. • Highly disrupted cell walls led to higher biodiesel yield in microwave irradiation. • Microwave irradiation is a promising direct technique with high biodiesel yields. - Abstract: The major challenges for industrial commercialized biodiesel production from microalgae are the high cost of downstream processing such as dewatering and drying, utilization of large volumes of solvent and laborious extraction processes. In order to address these issues the microwave irradiation method was used to produce biodiesel directly from wet microalgae biomass. This alternative method of biodiesel production from wet microalgae biomass is compared with the conventional water bath-assisted solvent extraction. The microwave irradiation extracted more lipids and high biodiesel conversion was obtained compared to the water bath-assisted extraction method due to the high cell disruption achieved and rapid transesterification. The total content of lipid extracted from microwave irradiation and water bath-assisted extraction were 38.31% and 23.01% respectively. The biodiesel produced using microwave irradiation was higher (86.41%) compared to the conventional method. Thus microwave irradiation is an attractive and promising technology to be used in the extraction and transesterification process for efficient biodiesel production

  6. Phototrophic pigment production with microalgae: biological constraints and opportunities

    NARCIS (Netherlands)

    Mulders, K.J.M.; Lamers, P.P.; Martens, D.E.; Wijffels, R.H.

    2014-01-01

    There is increasing interest in naturally produced colorants, and microalgae represent a bio-technologically interesting source due to their wide range of colored pigments, including chlorophylls (green), carotenoids (red, orange and yellow), and phycobiliproteins (red and blue). However, the concen

  7. Hazard and risk of herbicides for marine microalgae

    International Nuclear Information System (INIS)

    Due to their specific effect on photosynthesis, herbicides pose a potential threat to coastal and estuarine microalgae. However, comprehensive understanding of the hazard and risk of these contaminants is currently lacking. Therefore the aim of the present study was to investigate the toxic effects of four ubiquitous herbicides (atrazine, diuron, Irgarol®1051 and isoproturon) and herbicide mixtures on marine microalgae. Using a Pulse Amplitude Modulation (PAM) fluorometry based bioassay we demonstrated a clear species and herbicide specific toxicity and showed that the current environmental legislation does not protect algae sufficiently against diuron and isoproturon. Although a low actual risk of herbicides in the field was demonstrated, monitoring data revealed that concentrations occasionally reach potential effect levels. Hence it cannot be excluded that herbicides contribute to observed changes in phytoplankton species composition in coastal waters, but this is likely to occur only occasionally. - Highlights: • The hazard of herbicides for microalgae is compound and species specific. • In general a low risk although occasional potential effect levels are reached. • Current legislation does not protect marine microalgae sufficiently. - The hazard of herbicides in the coastal waters is compound and species specific and although the general risk in the field is low, occasionally potential effect levels are reached

  8. High Lipid Induction in Microalgae for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Peer M. Schenk

    2012-05-01

    Full Text Available Oil-accumulating microalgae have the potential to enable large-scale biodiesel production without competing for arable land or biodiverse natural landscapes. High lipid productivity of dominant, fast-growing algae is a major prerequisite for commercial production of microalgal oil-derived biodiesel. However, under optimal growth conditions, large amounts of algal biomass are produced, but with relatively low lipid contents, while species with high lipid contents are typically slow growing. Major advances in this area can be made through the induction of lipid biosynthesis, e.g., by environmental stresses. Lipids, in the form of triacylglycerides typically provide a storage function in the cell that enables microalgae to endure adverse environmental conditions. Essentially algal biomass and triacylglycerides compete for photosynthetic assimilate and a reprogramming of physiological pathways is required to stimulate lipid biosynthesis. There has been a wide range of studies carried out to identify and develop efficient lipid induction techniques in microalgae such as nutrients stress (e.g., nitrogen and/or phosphorus starvation, osmotic stress, radiation, pH, temperature, heavy metals and other chemicals. In addition, several genetic strategies for increased triacylglycerides production and inducibility are currently being developed. In this review, we discuss the potential of lipid induction techniques in microalgae and also their application at commercial scale for the production of biodiesel.

  9. Production of bio-jet fuel from microalgae

    Science.gov (United States)

    Elmoraghy, Marian

    The increase in petroleum-based aviation fuel consumption, the decrease in petroleum resources, the fluctuation of the crude oil price, the increase in greenhouse gas emission and the need for energy security are motivating the development of an alternate jet fuel. Bio-jet fuel has to be a drop in fuel, technically and economically feasible, environmentally friendly, greener than jet fuel, produced locally and low gallon per Btu. Bic jet fuel has been produced by blending petro-based jet fuel with microalgae biodiesel (Fatty Acid Methyl Ester, or simply FAME). Indoor microalgae growth, lipids extraction and transetrification to biodiesel are energy and fresh water intensive and time consuming. In addition, the quality of the biodiesel product and the physical properties of the bio-jet fuel blends are unknown. This work addressed these challenges. Minimizing the energy requirements and making microalgae growth process greener were accomplished by replacing fluorescent lights with light emitting diodes (LEDs). Reducing fresh water footprint in algae growth was accomplished by waste water use. Microalgae biodiesel production time was reduced using the one-step (in-situ transestrification) process. Yields up to 56.82 mg FAME/g dry algae were obtained. Predicted physical properties of in-situ FAME satisfied European and American standards confirming its quality. Lipid triggering by nitrogen deprivation was accomplished in order to increase the FAME production. Bio-jet fuel freezing points and heating values were measured for different jet fuel to biodiesel blend ratios.

  10. Evaluation of the Antioxidant Activity of Cell Extracts from Microalgae

    Directory of Open Access Journals (Sweden)

    F. Xavier Malcata

    2013-04-01

    Full Text Available A growing market for novel antioxidants obtained from non-expensive sources justifies educated screening of microalgae for their potential antioxidant features. Characterization of the antioxidant profile of 18 species of cyanobacteria (prokaryotic microalgae and 23 species of (eukaryotic microalgae is accordingly reported in this paper. The total antioxidant capacity, accounted for by both water- and lipid-soluble antioxidants, was evaluated by the (radical cation ABTS method. For complementary characterization of cell extracts, a deoxyribose assay was carried out, as well as a bacteriophage P22/Salmonella-mediated approach. The microalga Scenedesmus obliquus strain M2-1 exhibited the highest (p > 0.05 total antioxidant capacity (149 ± 47 AAU of intracellular extracts. Its scavenger activity correlated well with its protective effects against DNA oxidative damage induced by copper(II-ascorbic acid; and against decay in bacteriophage infection capacity induced by H2O2. Finally, performance of an Ames test revealed no mutagenic effects of the said extract.

  11. Insecticides induced biochemical changes in freshwater microalga Chlamydomonas mexicana.

    Science.gov (United States)

    Kumar, Muthukannan Satheesh; Kabra, Akhil N; Min, Booki; El-Dalatony, Marwa M; Xiong, Jiuqiang; Thajuddin, Nooruddin; Lee, Dae Sung; Jeon, Byong-Hun

    2016-01-01

    The effect of insecticides (acephate and imidacloprid) on a freshwater microalga Chlamydomonas mexicana was investigated with respect to photosynthetic pigments, carbohydrate and protein contents, fatty acids composition and induction of stress indicators including proline, superoxide dismutase (SOD) and catalase (CAT). C. mexicana was cultivated with 1, 5, 10, 15, 20 and 25 mg L(-1) of acephate and imidacloprid. The microalga growth increased with increasing concentrations of both insecticides up to 15 mg L(-1), beyond which the growth declined compared to control condition (without insecticides). C. mexicana cultivated with 15 mg L(-1) of both insecticides for 12 days was used for further analysis. The accumulation of photosynthetic pigments (chlorophyll and carotenoids), carbohydrates and protein was decreased in the presence of both insecticides. Acephate and imidacloprid induced the activities of superoxide dismutase (SOD) and catalase (CAT) and increased the concentration of proline in the microalga, which play a defensive role against various environmental stresses. Fatty acid analysis revealed that the fraction of polyunsaturated fatty acids decreased on exposure to both insecticides. C. mexicana also promoted 25 and 21% removal of acephate and imidacloprid, respectively. The biochemical changes in C. mexicana on exposure to acephate and imidacloprid indicate that the microalga undergoes an adaptive change in response to the insecticide-induced oxidative stress.

  12. Overcoming shear stress of microalgae cultures in sparged photobioreactors

    NARCIS (Netherlands)

    Barbosa, M.J.; Hadiyanto, H.; Wijffels, R.H.

    2004-01-01

    In the present work we identified and quantified the effect of hydrodynamic stress on two different microalgae strains, Dunaliella tertiolecta and D. salina, cultivated in bench-scale bubble columns. The cell death rate constant increased with increasing gas-entrance velocity at the sparger. Dunalie

  13. Cultivation of microalgae in a high irradiance area

    NARCIS (Netherlands)

    Cuaresma, M.

    2011-01-01


    Microalgae are a promising source of high-value products (i.e. carotenoids, ω-3 fatty acids), as well as feedstocks for food, bulk chemicals and biofuels. Industrial production is, however, still limited because the technology needs further development. One of the main bottlenecks is th

  14. Horizontal or vertical photobioreactors? How to improve microalgae photosynthetic efficiency

    NARCIS (Netherlands)

    Cuaresma, M.; Janssen, M.G.J.; Vilchez, C.; Wijffels, R.H.

    2011-01-01

    The productivity of a vertical outdoor photobioreactor was quantitatively assessed and compared to a horizontal reactor. Daily light cycles in southern Spain were simulated and applied to grow the microalgae Chlorella sorokiniana in a flat panel photobioreactor. The maximal irradiance around noon di

  15. Biodiesel Production from Microalgae by Extraction – Transesterification Method

    Directory of Open Access Journals (Sweden)

    Nguyen Thi Phuong Thao

    2013-11-01

    Full Text Available The environmental impact of using petroleum fuels has led to a quest to find a suitable alternative fuel source. In this study, microalgae were explored as a highly potential feedstock to produce biodiesel fuel. Firstly, algal oil is extracted from algal biomass by using organic solvents (n–hexan.  Lipid is contained in microalgae up to 60% of their weight. Then, Biodiesel is created through a chemical reaction known as transesterification between algal oil and alcohol (methanol with strong acid (such as H2SO4 as the catalyst. The extraction – transesterification method resulted in a high biodiesel yield (10 % of algal biomass and high FAMEs content (5.2 % of algal biomass. Biodiesel production from microalgae was studied through experimental investigation of transesterification conditions such as reaction time, methanol to oil ration and catalyst dosage which are deemed to have main impact on reaction conversion efficiency. All the parameters which were characterized for purified biodiesel such as free glycerin, total glycerin, flash point, sulfur content were analyzed according to ASTM standardDoi: http://dx.doi.org/10.12777/wastech.1.1.6-9Citation:  Thao, N.T.P., Tin, N.T., and Thanh, B.X. 2013. Biodiesel Production from Microalgae by Extraction – Transesterification Method. Waste Technology 1(1:6-9. Doi: http://dx.doi.org/10.12777/wastech.1.1.6-9

  16. Combustion of Microalgae Oil and Ethanol Blended with Diesel Fuel

    Directory of Open Access Journals (Sweden)

    Saddam H. Al-lwayzy

    2015-12-01

    Full Text Available Using renewable oxygenated fuels such as ethanol is a proposed method to reduce diesel engine emission. Ethanol has lower density, viscosity, cetane number and calorific value than petroleum diesel (PD. Microalgae oil is renewable, environmentally friendly and has the potential to replace PD. In this paper, microalgae oil (10% and ethanol (10% have been mixed and added to (80% diesel fuel as a renewable source of oxygenated fuel. The mixture of microalgae oil, ethanol and petroleum diesel (MOE20% has been found to be homogenous and stable without using surfactant. The presence of microalgae oil improved the ethanol fuel demerits such as low density and viscosity. The transesterification process was not required for oil viscosity reduction due to the presence of ethanol. The MOE20% fuel has been tested in a variable compression ratio diesel engine at different speed. The engine test results with MOE20% showed a very comparable engine performance of in-cylinder pressure, brake power, torque and brake specific fuel consumption (BSFC to that of PD. The NOx emission and HC have been improved while CO and CO2 were found to be lower than those from PD at low engine speed.

  17. Nitrogen and hydrophosphate affects glycolipids composition in microalgae.

    Science.gov (United States)

    Wang, Xin; Shen, Zhouyuan; Miao, Xiaoling

    2016-01-01

    Glycolipids had received increasing attention because of their uses in various industries like cosmetics, pharmaceuticals, food and machinery manufacture. Microalgae were competitive organisms to accumulate metabolic substance. However, using microalgae to produce glycolipid was rare at present. In this study, glycolipid content of Chlorella pyrenoidosa and Synechococcus sp. under different nitrate and hydrophosphate levels were investigated. The highest glycolipid contents of 24.61% for C. pyrenoidosa and 15.37% for Synechococcus sp. were obtained at nitrate absence, which were 17.19% for C. pyrenoidosa and 10.99% for Synechococcus sp. at 0.01 and 0 g L(-1) hydrophosphate, respectively. Glycolipid productivities of two microalgae could reach at more than 10.59 mg L(-1) d(-1). Nitrate absence induced at least 8.5% increase in MGDG, DGDG and SQDG, while hydrophosphate absence resulted in over 21.2% increase in DGDG and over 48.4% increase in SQDG and more than 22.2% decrease in MGDG in two microalgae. Simultaneous nitrate and hydrophosphate limitation could make further improvement of glycolipid accumulation, which was more than 25% for C. pyrenoidosa and 21% for Synechococcus sp. These results suggest that nitrogen and phosphorus limitation or starvation should be an efficient way to improve microalgal glycolipid accumulation. PMID:27440670

  18. Visual Simulation of Microalgae Growth in Bioregenerative Life Support System

    Science.gov (United States)

    Zhao, Ming

    Bioregenerative life support system is one of the key technologies for future human deep space exploration and long-term space missions. BLSS use biological system as its core unit in combination with other physical and chemical equipments, under the proper control and manipulation by crew to complete a specific task to support life. Food production, waste treatment, oxygen and water regeneration are all conducted by higher plants or microalgae in BLSS, which is the most import characteristic different from other kinds of life support systems. Microalgae is light autotrophic micro-organisms, light undoubtedly is the most import factor which limits its growth and reproduction. Increasing or decreasing the light intensity changes the growth rate of microalgae, and then regulates the concentration of oxygen and carbon dioxide in the system. In this paper, based on the mathematical model of microalgae which grew under the different light intensity, three-dimensional visualization model was built and realized through using 3ds max, Virtools and some other three dimensional software, in order to display its change and impacting on oxygen and carbon dioxide intuitively. We changed its model structure and parameters, such as establishing closed-loop control system, light intensity, temperature and Nutrient fluid’s velocity and so on, carried out computer virtual simulation, and observed dynamic change of system with the aim of providing visualization support for system research.

  19. Microalgae for the production of bulk chemicals and biofuels

    NARCIS (Netherlands)

    Wijffels, R.H.; Barbosa, M.J.; Eppink, M.H.M.

    2010-01-01

    The feasibility of microalgae production for biodiesel was discussed. Although algae are not yet produced at large scale for bulk applications, there are opportunities to develop this process in a sustainable way. It remains unlikely, however, that the process will be developed for biodiesel as the

  20. Nitrogen and hydrophosphate affects glycolipids composition in microalgae

    Science.gov (United States)

    Wang, Xin; Shen, Zhouyuan; Miao, Xiaoling

    2016-01-01

    Glycolipids had received increasing attention because of their uses in various industries like cosmetics, pharmaceuticals, food and machinery manufacture. Microalgae were competitive organisms to accumulate metabolic substance. However, using microalgae to produce glycolipid was rare at present. In this study, glycolipid content of Chlorella pyrenoidosa and Synechococcus sp. under different nitrate and hydrophosphate levels were investigated. The highest glycolipid contents of 24.61% for C. pyrenoidosa and 15.37% for Synechococcus sp. were obtained at nitrate absence, which were 17.19% for C. pyrenoidosa and 10.99% for Synechococcus sp. at 0.01 and 0 g L−1 hydrophosphate, respectively. Glycolipid productivities of two microalgae could reach at more than 10.59 mg L−1 d−1. Nitrate absence induced at least 8.5% increase in MGDG, DGDG and SQDG, while hydrophosphate absence resulted in over 21.2% increase in DGDG and over 48.4% increase in SQDG and more than 22.2% decrease in MGDG in two microalgae. Simultaneous nitrate and hydrophosphate limitation could make further improvement of glycolipid accumulation, which was more than 25% for C. pyrenoidosa and 21% for Synechococcus sp. These results suggest that nitrogen and phosphorus limitation or starvation should be an efficient way to improve microalgal glycolipid accumulation. PMID:27440670

  1. Potential of sponges and microalgae for marine biotechnology

    NARCIS (Netherlands)

    Wijffels, R.H.

    2008-01-01

    Marine organisms can be used to produce several novel products that have applications in new medical technologies, in food and feed ingredients and as biofuels. In this paper two examples are described: the development of marine drugs from sponges and the use of microalgae to produce bulk chemicals

  2. Techno-economical evaluation of protein extraction for microalgae biorefinery

    Science.gov (United States)

    Sari, Y. W.; Sanders, J. P. M.; Bruins, M. E.

    2016-01-01

    Due to scarcity of fossil feedstocks, there is an increasing demand for biobased fuels. Microalgae are considered as promising biobased feedstocks. However, microalgae based fuels are not yet produced at large scale at present. Applying biorefinery, not only for oil, but also for other components, such as carbohydrates and protein, may lead to the sustainable and economical microalgae-based fuels. This paper discusses two relatively mild conditions for microalgal protein extraction, based on alkali and enzymes. Green microalgae (Chlorella fusca) with and without prior lipid removal were used as feedstocks. Under mild conditions, more protein could be extracted using proteases, with the highest yields for microalgae meal (without lipids). The data on protein extraction yields were used to calculate the costs for producing 1 ton of microalgal protein. The processing cost for the alkaline method was € 2448 /ton protein. Enzymatic method performed better from an economic point of view with € 1367 /ton protein on processing costs. However, this is still far from industrially feasible. For both extraction methods, biomass cost per ton of produced product were high. A higher protein extraction yield can partially solve this problem, lowering processing cost to €620 and 1180 /ton protein product, using alkali and enzyme, respectively. Although alkaline method has lower processing cost, optimization appears to be better achievable using enzymes. If the enzymatic method can be optimized by lowering the amount of alkali added, leading to processing cost of € 633/ton protein product. Higher revenue can be generated when the residue after protein extraction can be sold as fuel, or better as a highly digestible feed for cattle.

  3. From transient response of a compact photobioreactor for microalgae cultivation

    Energy Technology Data Exchange (ETDEWEB)

    Dilay, Emerson; Ribeiro, Robert Luis Lara; Pulliam, Raevon; Mariano, Andre Bellin [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Nucleo de Pesquisa e Desenvolvimento em Energia Auto-Sustentavel; Ordonez, Juan Carlos [Florida State University, Tallahassee, FL (United States). Dept. of Mechanical Engineering and Center for Advanced Power Systems], E-mail: ordonez@caps.fsu.edu; Vargas, Jose Viriato Coelho [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Biofuels from microalgae are currently the subject of funded scientific research in many countries due to their high productivity of oil when compared with other crops. Microalgae can also be used in many important applications such as to obtain compounds of interest for food, chemicals, and pharmaceuticals. The high productivity of microalgae when compared with other crops is achieved because agricultural land is not mandatory for their cultivation, since they can be grown in open ponds, sea or vertical photo bioreactors. In this paper, a mathematical model is introduced for assessing the transient microalgae growth as a function of variable light intensity, temperature and environmental conditions in the daily cycle. Photo bioreactor geometry is considered as well. Light intensity is obtained from sun position, photo bioreactor geometry, and the installation location in the world. The photo bioreactor was discretized in space by the the volume element method. Balances of energy and species together with thermodynamics, heat transfer and chemistry empirical and theoretical correlations are applied to each volume element. Therefore, a system of ordinary differential equations with respect to time only is capable of delivering temperatures and concentrations as functions of space and time, even with a coarse mesh. The numerical results are capable of predicting the transient and steady state photo bioreactor biomass production with low computational time. Microalgae specific growth rate as a function of average light intensity inside the tubes and time was calculated. As a result, the model is expected to be a useful tool for simulation, design, and optimization of compact photo bioreactors. (author)

  4. Microalgae: the green gold of the future? : large-scale sustainable cultivation of microalgae for the production of bulk commodities

    OpenAIRE

    Wolkers, H.; Barbosa, M.J.; Kleinegris, D.M.M.; Bosma, R.; Wijffels, R.H.; Harmsen, P.F.H.

    2011-01-01

    The cultivation of microalgae can play an important role in environmentalfriendly production of raw materials for biodiesel. In addition, algae offer several other useful materials for the food and chemical industry. This booklet describes the possibilities for economically viable large scale algae cultivation for the production of valuable products and the role of the new algae centre in Wageningen, AlgaePARC.

  5. Biodiesel from wet microalgae: extraction with hexane after the microwave-assisted transesterification of lipids.

    Science.gov (United States)

    Cheng, Jun; Huang, Rui; Li, Tao; Zhou, Junhu; Cen, Kefa

    2014-10-01

    A chloroform-free novel process for the efficient production of biodiesel from wet microalgae is proposed. Crude biodiesel is produced through extraction with hexane after microwave-assisted transesterification (EHMT) of lipids in wet microalgae. Effects of different parameters, including reaction temperature, reaction time, methanol dosage, and catalyst dosage, on fatty acids methyl esters (FAMEs) yield are investigated. The yield of FAME extracted into the hexane from the wet microalgae is increased 6-fold after the transesterification of lipids. The yield of FAME obtained through EHMT of lipids in wet microalgae is comparable to that obtained through direct transesterification of dried microalgae biomass with chloroform; however, FAME content in crude biodiesel obtained through EHMT is 86.74%, while that in crude biodiesel obtained through the chloroform-based process is 75.93%. EHMT ensures that polar pigments present in microalgae are not extracted into crude biodiesel, which leads to a 50% reduction in nitrogen content in crude biodiesel.

  6. Digital signage sobre IP

    OpenAIRE

    Casademont Filella, Albert

    2012-01-01

    Projecte que versa sobre el disseny i la implementació d'un sistema de Digital Signage (Cartelleria Digital) sobre IP, creant un gestor que permeti controlar de forma remota tot un conjunt de petits dispositius connectats a pantalles que emeten continguts multimèdia com vídeos, imatges, feeds rss...

  7. Effects of Fluctuating Environments on the Selection of High Yielding Microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J. R.; Tillett, D. M.

    1987-02-27

    Microalgae have the potential of producing biomass with a high content of lipids at high productivities using seawater or saline ground water resources. Microalgal lipids are similar to vegetable oils and suitable for processing to liquid fuels. Engineering cost analysis studies have concluded that, at a favorable site, microalgae cultivation for fuel production could be economically viable. The major uncertainties involve the microalgae themselves: biomass and lipid productivity and culture stability.

  8. The microalga Chlamydomonas reinhardtii as a platform for the production of human protein therapeutics

    OpenAIRE

    Rasala, Beth A.; Mayfield, Stephen P.

    2011-01-01

    Microalgae are a diverse group of eukaryotic photosynthetic microorganisms. While microalgae play a crucial role in global carbon fixation and oxygen evolution, these organisms have recently gained much attention for their potential role in biotechnological and industrial applications, such as the production of biofuels. We investigated the potential of the microalga Chlamydomonas reinhardtii to be a platform for the production of human therapeutic proteins. C. reinhardtii is a unicellular fr...

  9. Lifecycle Assessment of Microalgae to Biofuel: Thermochemical Processing through Hydrothermal Liquefaction or Pyrolysis

    OpenAIRE

    Bennion, Edward P

    2014-01-01

    Microalgae have many desirable attributes as a renewable energy recourse. These include use of poor quality land, high yields, and it is not a food recourse. This research focusses on the energetic and environmental impact of processing microalgae into a renewable diesel. Two thermochemical bio-oil recovery processes are analyzed, pyrolysis and hydrothermal liquefaction (HTL). System boundaries include microalgae growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conv...

  10. Chitosan and Its Derivatives Applied in Harvesting Microalgae for Biodiesel Production: An Outlook

    OpenAIRE

    Guanyi Chen; Liu Zhao; Yun Qi; Yuan-Lu Cui

    2014-01-01

    Although oil-accumulating microalgae are a promising feedstock for biodiesel production, large-scale biodiesel production is not yet economically feasible. As harvesting accounts for an important part of total production cost, mass production of microalgae biodiesel requires an efficient low-energy harvesting strategy so as to make biodiesel production economically attractive. Chitosan has emerged as a favorable flocculating agent in harvesting of microalgae. The aim of this paper is to revie...

  11. Freshwater microalgae harvested via flocculation induced by pH decrease

    OpenAIRE

    Liu, Jiexia; Zhu, Yi; Tao, Yujun; Zhang, Yuanming; Li, Aifen; Li, Tao; Sang, Ming; Zhang, Chengwu

    2013-01-01

    Background Recent studies have demonstrated that microalga has been widely regarded as one of the most promising raw materials of biofuels. However, lack of an economical, efficient and convenient method to harvest microalgae is a bottleneck to boost their full-scale application. Many methods of harvesting microalgae, including mechanical, electrical, biological and chemical based, have been studied to overcome this hurdle. Results A new flocculation method induced by decreasing pH value of g...

  12. Transgene expression in microalgae – from tools to applications

    Directory of Open Access Journals (Sweden)

    Lior eDoron

    2016-04-01

    Full Text Available Microalgae comprise a biodiverse group of photosynthetic organisms that reside in water sources and sediments. The green microalgae Chlamydomonas reinhardtii was adopted as a useful model organism for studying various physiological systems. Its ability to grow under both photosynthetic and heterotrophic conditions allows efficient growth of non-photosynthetic mutants, making Chlamydomonas a useful genetic tool to study photosynthesis. In addition, this green alga can grow as haploid or diploid cells, similar to yeast, providing a powerful genetic system. As a result, easy and efficient transformation systems have been developed for Chlamydomonas, targeting both the chloroplast and nuclear genomes. Since microalgae comprise a rich repertoire of species that offer variable advantages for biotech and biomed industries, gene transfer technologies were further developed for many microalgae to allow for the expression of foreign proteins of interest. Expressing foreign genes in the chloroplast enables the targeting of foreign DNA to specific sites by homologous recombination. Chloroplast transformation also allows for the introduction of genes encoding several enzymes from a complex pathway, possibly as an operon. Expressing foreign proteins in the chloroplast can also be achieved by introducing the target gene into the nuclear genome, with the protein product bearing a targeting signal that directs import of the transgene-product into the chloroplast, like other endogenous chloroplast proteins. Integration of foreign genes into the nuclear genome is mostly random, resulting in large variability between different clones, such that extensive screening is required. The use of different selection modalities is also described, with special emphasis on the use of herbicides and metabolic markers which are considered to be friendly to the environment, as compared to drug-resistance genes that are commonly used. Finally, despite the development of a wide

  13. CO sub 2 sources for microalgae-based liquid fuel production

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D.; Karpuk, M.

    1990-08-01

    Researchers in the Aquatic Species Program at the Solar Energy Research Institute are developing species of microalgae that have high percentages of lipids, or oils. These lipids can be extracted and converted to diesel fuel substitutes. Because microalgae need carbon dioxide (CO{sub 2}) as a nutrient, optimal microalgae growth occurs in CO{sub 2}-saturated solutions. For this reason, the authors of this study sought to identify possible large-scale sources of CO{sub 2} for microalgae-based liquid fuels production. The authors concluded that several such promising sources exist. 42 refs., 14 figs., 10 tabs.

  14. The Growth Condition and Oil Production of Microalgae with Several Kinds of Plant Hormones

    Institute of Scientific and Technical Information of China (English)

    QIU Chen

    2016-01-01

    Microalgae as an important marine resources, rich in high content of polysaccharide, protein, fatty acids. The fatty acid content of microalgae is high, and its propagation speed is faster than herbaceous plants. It also has a high use value. The experiment tried on the basis of the screening of high yield oil microalgae, add different commonly used plant hormone, using growth monitoring, analysis of product components. Select several plant hormones to improve microalgae products production, provides guidance on the deep research and commercial production.

  15. Effect of Metals, Metalloids and Metallic Nanoparticles on Microalgae Growth and Industrial Product Biosynthesis: A Review

    Directory of Open Access Journals (Sweden)

    Krystian Miazek

    2015-10-01

    Full Text Available Microalgae are a source of numerous compounds that can be used in many branches of industry. Synthesis of such compounds in microalgal cells can be amplified under stress conditions. Exposure to various metals can be one of methods applied to induce cell stress and synthesis of target products in microalgae cultures. In this review, the potential of producing diverse biocompounds (pigments, lipids, exopolymers, peptides, phytohormones, arsenoorganics, nanoparticles from microalgae cultures upon exposure to various metals, is evaluated. Additionally, different methods to alter microalgae response towards metals and metal stress are described. Finally, possibilities to sustain high growth rates and productivity of microalgal cultures in the presence of metals are discussed.

  16. Shaking and Blending Effect on Microalgae Concentrates Size

    Directory of Open Access Journals (Sweden)

    LUDI PARWADANI AJI

    2012-03-01

    Full Text Available Microalgae concentrates (paste can be used as an alternative feed to replace live microalgae for aquaculture due to its nutritional value and convenience. However, the clumping of cells and negative buoyancy of algae concentrate can affect bivalve culture as bivalves only capture particles in suspension and ingest a certain size range of particles. This study investigated the effect of shaking and blending treatments on the preparation of food suspensions prepared from algae concentrates (Isochrysis and Pavlova. The results indicated that the higher the shaking time (5, 10, and 15 times or blending time (10, 30, and 60 seconds, the smaller was the diameter of the resulting algae particles. Moreover, the greater the volume of algae concentrate used in preparation, the larger the diameter of algae particles produced. Shaking may be the best option because it is cheaper and simpler. However, all the treatments provided a suitable particle size range for ingestion by bivalves.

  17. Considerations for the maximum production rates of triacylglycerol from microalgae

    International Nuclear Information System (INIS)

    In recent years, a wide variety of photobioreactors have emerged for producing triacylglycerol (TAG) from microalgae as a feedstock for biodiesel with wildly varying forecasts of TAG and biomass production rates. This research describes the general photobioreactor concept and the dominating factors that determine microalgal production and the maximum attainable production rate of TAG. The information necessary for such an assessment is obtained from published articles and the results are compared to published photobioreactor production rates. Results indicate that at most 9% conversion of available solar energy to TAG is thermodynamically possible, resulting in an annual areal production rate of no more than 23 l m-2 a-1. Given photosynthetic efficiencies and TAG contents of microalgae currently reported, production rates of no more than 15.8 l m-2 a-1 should be anticipated.

  18. Harvesting and processing of microalgae biomass fractions for biodiesel production

    International Nuclear Information System (INIS)

    There has been a recent resurgent interest in microalgae as an oil producer for biofuel applications. An adequate supply of nutrients and carbon dioxide enables algae to successfully transform light energy of the sun into energy - rich chemical compounds through photosynthesis. A strain with high lipids, successfully grown and harvested, could provide oil for most of our process by volume, which would then provide the most profitable output. Significant advances have also been made in upstream processing to generate cellular biomass and oil. However, the process of extracting and purifying of oil from algae continues to prove a significant challenge in producing both microalgae bioproducts and biofuel, as the oil extraction from algae is relatively energy-intensive and expensive. The aim of this review is to focus on different harvesting and extraction processes of algae for biodiesel production reported within the last decade. (author)

  19. Potential Production of Polyunsaturated Fatty Acids from Microalgae

    Directory of Open Access Journals (Sweden)

    Noer Abyor Handayani

    2011-07-01

    Full Text Available Currently, public awareness of healthcare importance increase. Polyunsaturated fatty acid is an essential nutrition for us, such arachidonic acid, docosahexaenoic acid and eicosapentaenoic acid. The need of Polyunsaturated fatty acid generally derived from fish oil, but fish oil has a high risk chemical contamination. Microalgae are single cell microorganism, one of Phaeodactylum tricornutum which have relatively high content of eicosapentaenoic acid (29,8%. Biotechnology market of Polyunsaturated fatty acid is very promising for both foods and feeds, because the availability of abundant raw materials and suitable to develop in the tropics. This literature review discusses about the content of Polyunsaturated fatty acid in microalgae, omega-3, omega-6, Polyunsaturated fatty acid production processes, and applications in public health

  20. Thermal decomposition dynamics and severity of microalgae residues in torrefaction.

    Science.gov (United States)

    Chen, Wei-Hsin; Huang, Ming-Yueh; Chang, Jo-Shu; Chen, Chun-Yen

    2014-10-01

    To figure out the torrefaction characteristics and weight loss dynamics of microalgae residues, the thermogravimetric analyses of two microalgae (Chlamydomonas sp. JSC4 and Chlorella sorokiniana CY1) residues are carried out. A parameter of torrefaction severity index (TSI) in the range of 0-1, in terms of weight loss ratio between a certain operation and a reference operation, is defined to indicate the degree of biomass thermal degradation due to torrefaction. The TSI profiles of the two residues are similar to each other; therefore, the parameter may be used to describe the torrefaction extents of various biomass materials. The curvature of TSI profile along light torrefaction is slight, elucidating its slight impact on biomass thermal degradation. The sharp curvature along severe torrefaction in the initial pretreatment period reveals that biomass upgraded with high temperature and short duration is more effective than using low temperature with long duration.

  1. Curvature-guided motility of microalgae in geometric confinement

    CERN Document Server

    Ostapenko, Tanya; Böddeker, Thomas; Kreis, Christian; Cammann, Jan; Mazza, Marco G; Bäumchen, Oliver

    2016-01-01

    Microorganisms often live in microhabitats that consist of a liquid phase and a plethora of typically curved interfaces. The ways in which motile cells possessing propulsive appendages sense and interact with the physical nature of their environment remains unclear today. For pusher-type microswimmers with rear-mounted flagella, such as bacteria and spermatozoa, cell trapping at a wall was attributed to contrasting microscopic mechanisms, namely hydrodynamic and contact interactions. Here, we demonstrate that, in confined spaces, the geometry of the habitat controls the motility of microalgae that propel themselves by the beating of two anterior flagella. Brownian dynamics simulations and analytical theory both quantitatively match the experimental data and capture a characteristic curvature scaling observed in the experiments. This curvature-guided navigation of the microalgae originates from only two essential ingredients: excluded volume resulting in predominantly ballistic swimming in confinement and the ...

  2. Characterization and Manipulation of Lipid Catabolism in Eukaryotic Microalgae /

    OpenAIRE

    Trentacoste, Emily Margaret

    2014-01-01

    The search for new sources of sustainable and renewable energy is one of the most important issues of our time. Broadening our energy base not only thwarts the issues of dependence on foreign oil and national energy security, but also creates a more stable and sustainable energy sector. Biomass is one such source of renewable energy that has been recently developed over the last few decades, and microalgae were identified half a century ago as potential producers of fuel-relevant molecules. M...

  3. CO2 capture and biofuels production with microalgae

    International Nuclear Information System (INIS)

    Microalgae cultivation in large open ponds is the only biological process capable of directly utilizing power plant flue gas CO2 for production of renewable fuels, such as biodiesel, thus mitigating the potential for global warming. Past and recent systems studies have concluded that in principle this concept could be economically feasible, but that this technology still requires both fundamental and applied long-term R ampersand D

  4. Spectral optical properties of selected photosynthetic microalgae producing biofuels

    International Nuclear Information System (INIS)

    This paper presents the spectral complex index of refraction of biofuel producing photosynthetic microalgae between 400 and 750 nm. They were retrieved from their experimentally measured average absorption and scattering cross-sections. The microalgae were treated as homogeneous polydisperse spheres with equivalent diameter such that their surface area was identical to that of their actual spheroidal shape. An inverse method was developed combining Lorentz–Mie theory as the forward method and genetic algorithm. The unicellular green algae Chlamydomonas reinhardtii strain CC125 and its truncated chlorophyll antenna transformants tla1, tlaX, and tla1-CW+ as well as Botryococcus braunii, Chlorella sp., and Chlorococcum littorale were investigated. These species were selected for their ability to produce either hydrogen gas or lipids for liquid fuel production. Their retrieved real and imaginary parts of the complex index of refraction were continuous functions of wavelength with absorption peaks corresponding to those of in vivo Chlorophylls a and b. The T-matrix method was also found to accurately predict the experimental measurements by treating the microalgae as axisymmetric spheroids with the experimentally measured major and minor diameter distributions and the retrieved spectral complex index of refraction. Finally, pigment mass fractions were also estimated from the retrieved absorption index. The method and/or the reported optical properties can be used in various applications from ocean remote sensing, carbon cycle study, as well as photobiological carbon dioxide mitigation and biofuel production. -- Highlights: ► Retrieval of optical properties from average absorption and scattering cross-sections. ► Inverse method based on Lorentz–Mie theory and genetic algorithm. ► Refraction and absorption indices of selected microalgae between 400 and 750 nm. ► Determination of pigment concentrations from absorption index. ► Good agreement between T

  5. Potential Production of Polyunsaturated Fatty Acids from Microalgae

    OpenAIRE

    Noer Abyor Handayani; Dessy Ariyanti; Hady Hadiyanto

    2011-01-01

    Currently, public awareness of healthcare importance increase. Polyunsaturated fatty acid is an essential nutrition for us, such arachidonic acid, docosahexaenoic acid and eicosapentaenoic acid. The need of Polyunsaturated fatty acid generally derived from fish oil, but fish oil has a high risk chemical contamination. Microalgae are single cell microorganism, one of Phaeodactylum tricornutum which have relatively high content of eicosapentaenoic acid (29,8%). Biotechnology market of Polyunsat...

  6. Biodiesel de microalgas: avanços e desafios

    OpenAIRE

    André Luiz Custódio Franco; Ivon Pinheiro Lôbo; Rosenira Serpa da Cruz; Cláudia Maria Luz Lapa Teixeira; José Adolfo de Almeida Neto; Rafael Silva Menezes

    2013-01-01

    Microalgae biomass has been described by several authors as the raw material with the greatest potential to meet the goals of replacing petroleum diesel by biodiesel while not competing with arable land suitable for food production. Research groups in different countries are seeking the most appropriate production model for productivity, economic viability and environmental sustainability. This review focused on recent advances and challenges of technology for the production of biodiesel from...

  7. Fuel Property of Biodiesel Made from Microalgae (Chlorella Sp.)

    OpenAIRE

    S. V. Kelaiya,; P. M. Chauhan; S. H. Akbari

    2015-01-01

    Microalgae chlorella is an organism capable of photosynthesis that is less than 2mm in diameter. The biodiesel extracted from algae using chloroform/methanol extraction solvent system then undergone three different transesterification processes based on three different catalysts viz. Alkali catalyst, Acid catalyst and Enzymatic catalyst with two temperature (50°C and 60 °C) and with 1:5 methanol to bio-oil ratio. After transesterification using different catalysts, the fuel properties were ...

  8. High Lipid Induction in Microalgae for Biodiesel Production

    OpenAIRE

    Schenk, Peer M.; Sharma, Kalpesh K.; Holger Schuhmann

    2012-01-01

    Oil-accumulating microalgae have the potential to enable large-scale biodiesel production without competing for arable land or biodiverse natural landscapes. High lipid productivity of dominant, fast-growing algae is a major prerequisite for commercial production of microalgal oil-derived biodiesel. However, under optimal growth conditions, large amounts of algal biomass are produced, but with relatively low lipid contents, while species with high lipid contents are typically slow growing. Ma...

  9. Can spherical eukaryotic microalgae cells be treated as optically homogeneous?

    Science.gov (United States)

    Bhowmik, Arka; Pilon, Laurent

    2016-08-01

    This study aims to answer the question of whether spherical unicellular photoautotrophic eukaryotic microalgae cells, consisting of various intracellular compartments with their respective optical properties, can be modeled as homogeneous spheres with some effective complex index of refraction. The spectral radiation characteristics in the photosynthetically active region of a spherical heterogeneous microalgae cell, representative of Chlamydomonas reinhardtii and consisting of spherical compartments corresponding to the cell wall, cytoplasm, chloroplast, nucleus, and mitochondria, were estimated using the superposition T-matrix method. The effects of the presence of intracellular lipids and/or starch accumulation caused by stresses, such as nitrogen limitation, were explored. Predictions by the T-matrix method were qualitatively and quantitatively consistent with experimental measurements for various microalgae species. The volume-equivalent homogeneous sphere approximation with volume-averaged effective complex index of refraction gave accurate estimates of the spectral (i) absorption and (ii) scattering cross sections of the heterogeneous cells under both nitrogen-replete and nitrogen-limited conditions. In addition, the effect of a strongly refracting cell wall, representative of Chlorella vulgaris, was investigated. In this case, for the purpose of predicting their integral radiation characteristics, the microalgae should be represented as a coated sphere with a coating corresponding to the cell wall and a homogeneous core with volume-averaged complex index of refraction for the rest of the cell. However, both homogeneous sphere and coated sphere approximations predicted strong resonances in the scattering phase function and spectral backscattering cross section that were not observed in that of the heterogeneous cells. PMID:27505647

  10. CO{sub 2} capture and biofuels production with microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J.R. [Univ. of California, Berkeley, CA (United States)

    1995-11-01

    Microalgae cultivation in large open ponds is the only biological process capable of directly utilizing power plant flue gas CO{sub 2} for production of renewable fuels, such as biodiesel, thus mitigating the potential for global warming. Past and recent systems studies have concluded that in principle this concept could be economically feasible, but that this technology still requires both fundamental and applied long-term R&D.

  11. Ultrafiltros sobre ω.

    OpenAIRE

    Mancilla Hernández, Salvador

    2012-01-01

    El objetivo del presente trabajo estudiar los ideales y filtros sobre conjuntos numerables, los que comúnmente conocemos como filtros sobre ω o ideales sobre ω. Dentro de estos, nos enfocaremos en la clase de I-ultrafiltros los cuales fueron estudiados por James Baumgartner en [11]. Y dentro de esta clase de ultrafiltros, nos concentraremos cuando I es {A ⊆ ω : n∈A g(n) < ∞}, también conocido como ideal sumable con respecto a g, donde g es una sucesión de números reales no negativ...

  12. Prospects of biodiesel production from microalgae in India

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Shakeel A.; Hussain, Mir Z.; Prasad, S. [Division of Environmental Sciences, Indian Agricultural Research Institute, New Delhi 110012 (India); Rashmi; Banerjee, U.C. [Department of Pharmaceutical Technology (Biotechnology), National Institute of Pharmaceutical and Education Research (NIPER), Sector 67, Phase X, S.A.S. Nagar, Mohali 160062, Punjab (India)

    2009-12-15

    Energy is essential and vital for development, and the global economy literally runs on energy. The use of fossil fuels as energy is now widely accepted as unsustainable due to depleting resources and also due to the accumulation of greenhouse gases in the environment. Renewable and carbon neutral biodiesel are necessary for environmental and economic sustainability. Biodiesel demand is constantly increasing as the reservoir of fossil fuel are depleting. Unfortunately biodiesel produced from oil crop, waste cooking oil and animal fats are not able to replace fossil fuel. The viability of the first generation biofuels production is however questionable because of the conflict with food supply. Production of biodiesel using microalgae biomass appears to be a viable alternative. The oil productivity of many microalgae exceeds the best producing oil crops. Microalgae are photosynthetic microorganisms which convert sunlight, water and CO{sub 2} to sugars, from which macromolecules, such as lipids and triacylglycerols (TAGs) can be obtained. These TAGs are the promising and sustainable feedstock for biodiesel production. Microalgal biorefinery approach can be used to reduce the cost of making microalgal biodiesel. Microalgal-based carbon sequestration technologies cover the cost of carbon capture and sequestration. The present paper is an attempt to review the potential of microalgal biodiesel in comparison to the agricultural crops and its prospects in India. (author)

  13. Phylogenetic Diversity in the Macromolecular Composition of Microalgae

    Science.gov (United States)

    Finkel, Zoe V.; Follows, Mick J.; Liefer, Justin D.; Brown, Chris M.; Benner, Ina; Irwin, Andrew J.

    2016-01-01

    The elemental stoichiometry of microalgae reflects their underlying macromolecular composition and influences competitive interactions among species and their role in the food web and biogeochemistry. Here we provide a new estimate of the macromolecular composition of microalgae using a hierarchical Bayesian analysis of data compiled from the literature. The median macromolecular composition of nutrient-sufficient exponentially growing microalgae is 32.2% protein, 17.3% lipid, 15.0% carbohydrate, 17.3% ash, 5.7% RNA, 1.1% chlorophyll-a and 1.0% DNA as percent dry weight. Our analysis identifies significant phylogenetic differences in macromolecular composition undetected by previous studies due to small sample sizes and the large inherent variability in macromolecular pools. The phylogenetic differences in macromolecular composition lead to variations in carbon-to-nitrogen ratios that are consistent with independent observations. These phylogenetic differences in macromolecular and elemental composition reflect adaptations in cellular architecture and biochemistry; specifically in the cell wall, the light harvesting apparatus, and storage pools. PMID:27228080

  14. Spectral optical properties of selected photosynthetic microalgae producing biofuels

    Science.gov (United States)

    Lee, Euntaek; Heng, Ri-Liang; Pilon, Laurent

    2013-01-01

    This paper presents the spectral complex index of refraction of biofuel producing photosynthetic microalgae between 400 and 750 nm. They were retrieved from their experimentally measured average absorption and scattering cross-sections. The microalgae were treated as homogeneous polydisperse spheres with equivalent diameter such that their surface area was identical to that of their actual spheroidal shape. An inverse method was developed combining Lorentz-Mie theory as the forward method and genetic algorithm. The unicellular green algae Chlamydomonas reinhardtii strain CC125 and its truncated chlorophyll antenna transformants tla1, tlaX, and tla1-CW+ as well as Botryococcus braunii, Chlorella sp., and Chlorococcum littorale were investigated. These species were selected for their ability to produce either hydrogen gas or lipids for liquid fuel production. Their retrieved real and imaginary parts of the complex index of refraction were continuous functions of wavelength with absorption peaks corresponding to those of in vivo Chlorophylls a and b. The T-matrix method was also found to accurately predict the experimental measurements by treating the microalgae as axisymmetric spheroids with the experimentally measured major and minor diameter distributions and the retrieved spectral complex index of refraction. Finally, pigment mass fractions were also estimated from the retrieved absorption index. The method and/or the reported optical properties can be used in various applications from ocean remote sensing, carbon cycle study, as well as photobiological carbon dioxide mitigation and biofuel production.

  15. Direct visualization of microalgae rupture by ultrasound-driven bubbles

    Science.gov (United States)

    Pommella, Angelo; Harun, Irina; Pouliopoulos, Antonis; Choi, James J.; Hellgardt, Klaus; Garbin, Valeria

    2015-11-01

    Cell rupture induced by ultrasound is central to applications in biotechnology. For instance, cell disruption is required in the production of biofuels from microalgae (unicellular species of algae). Ultrasound-induced cavitation, bubble collapse and jetting are exploited to induce sufficiently large viscous stresses to cause rupture of the cell membranes. It has recently been shown that seeding the flow with bubbles that act as cavitation nuclei significantly reduces the energy cost for cell processing. However, a fundamental understanding of the conditions for rupture of microalgae in the complex flow fields generated by ultrasound-driven bubbles is currently lacking. We perform high-speed video microscopy to visualize the miscroscale details of the interaction of Chlamydomonas reinhardtii , microalgae of about 10 μm in size, with ultrasound-driven microbubbles of 2-200 μm in diameter. We investigate the efficiency of cell rupture depending on ultrasound frequency and pressure amplitude (from 10 kPa up to 1 MPa), and the resulting bubble dynamics regimes. In particular we compare the efficiency of membrane rupture in the acoustic microstreaming flow induced by linear oscillations, with the case of violent bubble collapse and jetting. V.G. acknowledges partial support from the European Commission (FP7-PEOPLE-2013-CIG), Grant No. 618333.

  16. Protein N-glycosylation in eukaryotic microalgae and its impact on the production of nuclear expressed biopharmaceuticals

    OpenAIRE

    Mathieu-Rivet, Elodie; Kiefer-Meyer, Marie-Christine; Vanier, Gaëtan; Ovide, Clément; Burel, Carole; Lerouge, Patrice; Bardor, Muriel

    2014-01-01

    Microalgae are currently used for the production of food compounds. Recently, few microalgae species have been investigated as potential biofactories for the production of biopharmaceuticals. Indeed in this context, microalgae are cheap, classified as Generally Recognized As Safe (GRAS) organisms and can be grown easily. However, problems remain to be solved before any industrial production of microalgae-made biopharmaceuticals. Among them, post-translational modifications of the proteins nee...

  17. Biodiesel renovável derivado de microalgas: avanços e perspectivas tecnológicas

    Directory of Open Access Journals (Sweden)

    Claudio M. P. Pereira

    2012-01-01

    Full Text Available Microalgae are a promising source of raw material for biodiesel production. This review discusses the latest developments related to the application of microalgae biomass for biodiesel production. Characterization of fatty acid of microalgae and comparisons with other sources of raw materials and processes are presented. Furthermore, technological perspectives and approaches for growing microalgae in photobioreactors, microalgal oil extraction techniques, and procedures for synthesizing biodiesel are reviewed.

  18. Growth and lipid accumulation of microalgae from fluctuating brackish and sea water locations in South East Queensland – Australia

    OpenAIRE

    Van Thang eDuong; Thomas-Hall, Skye R.; Peer eSchenk

    2015-01-01

    One challenge constraining the use of microalgae in the food and biofuels industry is growth and lipid accumulation. Microalgae with high growth characteristics are more likely to originate from the local environment. However, to be commercially effective, in addition to high growth microalgae must also have high lipid productivities and contain the desired fatty acids for their intended use. We isolated microalgae from intertidal locations in South East Queensland, Australia with adverse or ...

  19. Growth and lipid accumulation of microalgae from fluctuating brackish and sea water locations in South East Queensland—Australia

    OpenAIRE

    Duong, Thang; Thomas-Hall, Skye R.; Schenk, Peer M.

    2015-01-01

    One challenge constraining the use of microalgae in the food and biofuels industry is growth and lipid accumulation. Microalgae with high growth characteristics are more likely to originate from the local environment. However, to be commercially effective, in addition to high growth microalgae must also have high lipid productivities and contain the desired fatty acids for their intended use. We isolated microalgae from intertidal locations in South East Queensland, Australia with adverse or ...

  20. Generación de materia orgánica acoplada a la eliminación de CO2 por Anabaena sp. ATCC 33047 y su utilización para la remoción de cadmio

    OpenAIRE

    Esteban Clares, Marta

    2011-01-01

    El incremento del nivel atmosférico de dióxido de carbono, gas de efecto invernadero, y la necesidad de reducir el mismo constituye un problema global de ingentes proporciones. Una aproximación a este problema consiste en la utilización de microorganismos fotosintéticos para la retirada del CO2. Microalgas y cianobacterias se encuentran entre los más efectivos fijadores de CO2 del planeta, con rendimientos considerablemente superiores a los de los cultivos agrícolas más productivos. En este t...

  1. Sorting cells of the microalga Chlorococcum littorale with increased triacylglycerol productivity

    NARCIS (Netherlands)

    Dominguez Teles, I.; Zwart, van der Mathijs; Kleinegris, D.M.M.; Wijffels, R.H.; Barbosa, M.J.

    2016-01-01

    Despite extensive research in the last decades, microalgae are still only economically feasible for high valued markets. Strain improvement is a strategy to increase productivities, hence reducing costs. In this work, we focus on microalgae selection: taking advantage of the natural biological varia

  2. The impact of nitrogen starvation on the dynamics of triacylglycerol accumulation in nine microalgae strains

    NARCIS (Netherlands)

    Breuer, G.; Lamers, P.P.; Martens, D.E.; Draaisma, R.B.; Wijffels, R.H.

    2012-01-01

    Microalgae-derived lipids are an alternative to vegetable and fossil oils, but lipid content and quality vary among microalgae strains. Selection of a suitable strain for lipid production is therefore of paramount importance. Based on published results for 96 species, nine strains were selected to s

  3. Lipid-based liquid biofuels from autotrophic microalgae: energetic and environmental performance

    NARCIS (Netherlands)

    L. Reijnders

    2013-01-01

    Commercial cultivation of autotrophic microalgae for food production dates back to the 1950s. Autotrophic microalgae have also been proposed as a source for lipid-based liquid biofuels. As yet, there is no commercial production of such biofuels and estimated near-term prices are far in excess of fos

  4. Techno-economic assessment of micro-algae as feedstock for renewable bio-energy production

    NARCIS (Netherlands)

    Jonker, J.G.G.; Faaij, A.P.C.

    2013-01-01

    This paper determines the energy consumption ratio and overall bio-energy production costs of microalgae cultivation, harvesting and conversion to secondary energy carriers, thus helping to clarify future perspectives of micro-algae production for energy purposes. A limitation growth model is develo

  5. Inventory of Sources of Available Saline Waters for Microalgae Mass Culture in the State of Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, L. G.; Olson, K. L.; Wallace, M. G.; Osborn, M. D.

    1986-06-25

    The Solar Energy Research Institute (SERI) is conducting research on the development of microalgae biomass systems for the production of liquid fuels. Particularly appealing at this time, is the idea of using indigenous resources of the Southwest for large-scale production of microalgae.

  6. Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content.

    Science.gov (United States)

    Biller, P; Ross, A B

    2011-01-01

    A range of model biochemical components, microalgae and cyanobacteria with different biochemical contents have been liquefied under hydrothermal conditions at 350 °C, ∼200 bar in water, 1M Na(2)CO(3) and 1M formic acid. The model compounds include albumin and a soya protein, starch and glucose, the triglyceride from sunflower oil and two amino acids. Microalgae include Chlorella vulgaris,Nannochloropsis occulata and Porphyridium cruentum and the cyanobacteria Spirulina. The yields and product distribution obtained for each model compound have been used to predict the behaviour of microalgae with different biochemical composition and have been validated using microalgae and cyanobacteria. Broad agreement is reached between predictive yields and actual yields for the microalgae based on their biochemical composition. The yields of bio-crude are 5-25 wt.% higher than the lipid content of the algae depending upon biochemical composition. The yields of bio-crude follow the trend lipids>proteins>carbohydrates.

  7. Advances in Microalgae-Derived Phytosterols for Functional Food and Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Xuan Luo

    2015-07-01

    Full Text Available Microalgae contain a variety of bioactive lipids with potential applications in aquaculture feed, biofuel, food and pharmaceutical industries. While microalgae-derived polyunsaturated fatty acid (PUFA and their roles in promoting human health have been extensively studied, other lipid types from this resource, such as phytosterols, have been poorly explored. Phytosterols have been used as additives in many food products such as spread, dairy products and salad dressing. This review focuses on the recent advances in microalgae-derived phytosterols with functional bioactivities and their potential applications in functional food and pharmaceutical industries. It highlights the importance of microalgae-derived lipids other than PUFA for the development of an advanced microalgae industry.

  8. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa [Silla Univ., Busan (Korea, Republic of)

    2013-07-01

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals.

  9. Marine microalgae growth and carbon partitioning as a function of nutrient availability.

    Science.gov (United States)

    Fernandes, Tomásia; Fernandes, Igor; Andrade, Carlos A P; Cordeiro, Nereida

    2016-08-01

    To understand in which way the structural differences of three marine microalgae (Nannochloropsis gaditana, Rhodomonas marina and Isochrysis sp.) affect their carbon partitioning, growth and applicability; a stoichiometric imbalance was imposed by steady carbon and other nutrients variation. Towards high nutrients concentrations/low carbon availability a decrease of 12-51% in C/N microalgae ratio was observed and maximum cell densities were achieved. Moreover, linear correlation between the nutrient input and microalgae protein content were observed. The macromolecular ratios pointed that carbohydrate was the main contributor for the C/N decrement. Although lipid content in R. marina remained constant throughout the experiment, a rise of 37-107% in N. gaditana and Isochrysis sp. was verified. Lipid fractions revealed high percentages of glycolipids in all microalgae (57-73% of total lipids). The present study shows an easy way to understand and modulate microalgae carbon partitioning relying on the field of application. PMID:27179298

  10. Anaerobic digestion of microalgae residues resulting from the biodiesel production process

    International Nuclear Information System (INIS)

    The recovery of methane from post transesterified microalgae residues has the potential to improve the renewability of the 'microalgae biomass to biodiesel' conversion process as well as reduce its cost and environmental impact. This paper deals with the anaerobic digestion of microalgae biomass residues (post transesterification) using semi-continuously fed reactors. The influence of substrate loading concentrations and hydraulic retention times on the specific methane yield of the anaerobically digested microalgae residues was investigated. The co-digestion of the microalgae residues with glycerol as well as the influence of temperature was also examined. It was found that the hydraulic retention period was the most significant variable affecting methane production from the residues, with periods (>5 days) corresponding to higher energy recovery. The methane yield was also improved by a reduction in the substrate loading rates, with an optimum substrate carbon to nitrogen ratio of 12.44 seen to be required for the digestion process.

  11. Intensification of microalgae drying and oil extraction process by vapor recompression and heat integration.

    Science.gov (United States)

    Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Kitamura, Yutaka

    2016-05-01

    Reducing energy penalty caused by drying and oil extraction is the most critical challenge in microalgae biodiesel production. In this study, vapor recompression and heat integration are utilized to optimize the performance of wet microalgae drying and oil extraction. In the microalgae drying stage, the hot exhaust stream is recompressed and coupled with wet microalgae to recover the condensate heat. In the oil extraction stage, the exergy rate of recovered solvent is also elevated by compressor and then exchanged heat with feed and bottom stream in the distillation column. Energy and mass balance of the intensified process is investigated and compared with the conventional microalgae drying-extraction process. The simulation results indicated that the total energy consumption of the intensified process can be saved by 52.4% of the conventional route.

  12. Intensification of microalgae drying and oil extraction process by vapor recompression and heat integration.

    Science.gov (United States)

    Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Kitamura, Yutaka

    2016-05-01

    Reducing energy penalty caused by drying and oil extraction is the most critical challenge in microalgae biodiesel production. In this study, vapor recompression and heat integration are utilized to optimize the performance of wet microalgae drying and oil extraction. In the microalgae drying stage, the hot exhaust stream is recompressed and coupled with wet microalgae to recover the condensate heat. In the oil extraction stage, the exergy rate of recovered solvent is also elevated by compressor and then exchanged heat with feed and bottom stream in the distillation column. Energy and mass balance of the intensified process is investigated and compared with the conventional microalgae drying-extraction process. The simulation results indicated that the total energy consumption of the intensified process can be saved by 52.4% of the conventional route. PMID:26871956

  13. Effect of Lignocellulose Related Compounds on Microalgae Growth and Product Biosynthesis: A Review

    Directory of Open Access Journals (Sweden)

    Krystian Miazek

    2014-07-01

    Full Text Available Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated.

  14. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    International Nuclear Information System (INIS)

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals

  15. Efeito do meio Erd Schreiber no cultivo das microalgas Dunaliella salina, Tetraselmis chuii e Isochrysis galbana - DOI: 10.4025/actascibiolsci.v28i2.1037 Erd Schreiber medium effect in culture of microalgae Dunaliella salina, Tetraselmis chuii and Isochrysis galbana - DOI: 10.4025/actascibiolsci.v28i2.1037

    Directory of Open Access Journals (Sweden)

    Vera Lucia Mota Klein

    2006-03-01

    Full Text Available As microalgas são utilizadas como fonte de alimento em aqüicultura. Neste trabalho cultivaram-se D. salina, T. chuii e I. galbana. O objetivo do trabalho consistiu em determinar o efeito do meio Erd Schreiber sobre o seu crescimento. Iniciou-se o cultivo com a mistura de 200 mg de Na2HPO4,7H2O, 100 mg de NaNO3 e 50 mL de extrato de solo. No monitoramento, manteve-se a temperatura entre 24 - 28oC, a salinidade a 34 ppt, à iluminação constante, a densidade celular com uma câmara de Neubauer e um microscópio binocular modelo ZEISS. Como resultado, I. galbana, D. salina e T. chuii atingiram 969 104 cel/mL, 457 x 104 cel/mL e 258,66 x 104 cel/mL, respectivamente, e os coeficientes angulares b foram 3,76 x 104 cel./mL/dia, 6,84 x 104 cel./mL/dia e 2,08 x 104 cel./mL/dia respectivamente, indicando bom desempenho de todas as microalgas no meio Erd Shreiber.The microalgae is used as food source in aqüicultura. In this work they had cultivated D. salina , T. chuii and I. galbana. The objective of the work is to determine the effect of Erd Schreiber´s culture medium on the microalgae growth. The culture initiated mixting 200mg of Na2HPO4,7H2O, 100 mg of NaNO3 and 50 mL of soil extract. During the culture the temperature had varied between 24 and 28oC, the salinity was fixed on 34 %o, and the illumination was maintained constant. The assessment of the culture was made by a chamber of Neubauer and a binocular microscope ZEISS model. As result I. galbana D. salina and T.chuii reached 969 104 cel/mL, 457 x 104 cel/mL and 258,66 x 104 cel/mL respectively and as angular coefficient 3,76 x 104 cel/mL/dia, 6,84 x 104 cel/mL/dia and 2,08 104 x cel/mL/dia respectively, showing good answer of the microalgae to the effect of Erd Schreiber´ s medium.

  16. Adaptation of microalgae to a gradient of continuous petroleum contamination

    International Nuclear Information System (INIS)

    In order to study adaptation of microalgae to petroleum contamination, we have examined an environmental stress gradient by crude oil contamination in the Arroyo Minero River (AMR), Argentina. Underground crude oil has constantly leaked out since 1915 as a consequence of test drilling for possible petroleum exploitation. Numerous microalgae species proliferated in AMR upstream of the crude oil spill. In contrast, only four microalgal species were detected in the crude oil spill area. Species richness increases again downstream. Microalgae biomass in the crude oil spill area is dominated by a mesophile species, Scenedesmus sp. Effects of oil samples from AMR spill on photosynthetic performance and growth were studied using laboratory cultures of two Scenedesmus sp. strains. One strain (Se-co) was isolated from the crude oil spill area. The other strain (Se-pr) was isolated from a pristine area without petroleum contamination. Crude oil has undetectable effects on Se-co strain. In contrast crude oil rapidly destroys Se-pr strain. However, Se-pr strain can adapt to low doses of petroleum (≤3% v/v total hydrocarbons/water) by means of physiological acclimatization. In contrast, only rare crude oil-resistant mutants are able to grow under high levels of crude oil (≥10% v/v total hydrocarbons/water). These crude oil-resistant mutants have arisen through rare spontaneous mutations that occur prior to crude oil exposure. Species richness in different areas of AMR is closely connected to the kind of mechanism (genetic adaptation vs. physiological acclimatization) that allows adaptation. Resistant-mutants are enough to assure the survival of microalgal species under catastrophic crude oil spill.

  17. Longitudinal Analysis of Microbiota in Microalga Nannochloropsis salina Cultures.

    Science.gov (United States)

    Geng, Haifeng; Sale, Kenneth L; Tran-Gyamfi, Mary Bao; Lane, Todd W; Yu, Eizadora T

    2016-07-01

    Large-scale open microalgae cultivation has tremendous potential to make a significant contribution to replacing petroleum-based fuels with biofuels. Open algal cultures are unavoidably inhabited with a diversity of microbes that live on, influence, and shape the fate of these ecosystems. However, there is little understanding of the resilience and stability of the microbial communities in engineered semicontinuous algal systems. To evaluate the dynamics and resilience of the microbial communities in microalgae biofuel cultures, we conducted a longitudinal study on open systems to compare the temporal profiles of the microbiota from two multigenerational algal cohorts, which include one seeded with the microbiota from an in-house culture and the other exogenously seeded with a natural-occurring consortia of bacterial species harvested from the Pacific Ocean. From these month-long, semicontinuous open microalga Nannochloropsis salina cultures, we sequenced a time-series of 46 samples, yielding 8804 operational taxonomic units derived from 9,160,076 high-quality partial 16S rRNA sequences. We provide quantitative evidence that clearly illustrates the development of microbial community is associated with microbiota ancestry. In addition, N. salina growth phases were linked with distinct changes in microbial phylotypes. Alteromonadeles dominated the community in the N. salina exponential phase whereas Alphaproteobacteria and Flavobacteriia were more prevalent in the stationary phase. We also demonstrate that the N. salina-associated microbial community in open cultures is diverse, resilient, and dynamic in response to environmental perturbations. This knowledge has general implications for developing and testing design principles of cultivated algal systems. PMID:26956183

  18. Carbon dioxide fixation by microalgae cultivated in open bioreactors

    International Nuclear Information System (INIS)

    Highlights: → We studied the growth and CO2 fixation by Spirulina LEB18 and Chlorella kessleri. → The maximum dailyfixation was obtained for Spirulina with an injection of 6% of CO2. → The microalgae presented growth during the 20 d of culture with up to 18% of CO2. → The use of CO2 from industrial generation decreases the cost of producing biomass. - Abstract: The biofixation of carbon dioxide (CO2) by microalgae has been proven to be an efficient and economical method, mainly due to the photosynthetic ability of these microorganisms to use this gas as a source of nutrients for their development. The aim of this work was to study the growth of Spirulina LEB18 and Chlorella kessleri microalgae, exposed to controlled and non-controlled conditions, with the injection of different concentrations of CO2. The cultures was carried out in 6 L open raceway ponds, under controlled conditions at 30 oC and 39 μE m-2 s-1 and under non-controlled conditions, protected by a tunnel of transparent film. The experiments were subjected to CO2 injections at concentrations of 0.038, 6, 12 and 18% (v/v). The highest concentration of biomass (4.95 g L-1) and maximum daily fixation (0.21 g g-1 d-1) were obtained for Spirulina LEB18 in culture that was prepared in non-controlled conditions with an injection of 6% (v/v) of CO2. C. kessleri had maximum (p -1) when grown with 18% (v/v) of CO2 in non-controlled conditions of cultivation.

  19. DNA Barcoding Green Microalgae Isolated from Neotropical Inland Waters.

    Science.gov (United States)

    Hadi, Sámed I I A; Santana, Hugo; Brunale, Patrícia P M; Gomes, Taísa G; Oliveira, Márcia D; Matthiensen, Alexandre; Oliveira, Marcos E C; Silva, Flávia C P; Brasil, Bruno S A F

    2016-01-01

    This study evaluated the feasibility of using the Ribulose Bisphosphate Carboxylase Large subunit gene (rbcL) and the Internal Transcribed Spacers 1 and 2 of the nuclear rDNA (nuITS1 and nuITS2) markers for identifying a very diverse, albeit poorly known group, of green microalgae from neotropical inland waters. Fifty-one freshwater green microalgae strains isolated from Brazil, the largest biodiversity reservoir in the neotropics, were submitted to DNA barcoding. Currently available universal primers for ITS1-5.8S-ITS2 region amplification were sufficient to successfully amplify and sequence 47 (92%) of the samples. On the other hand, new sets of primers had to be designed for rbcL, which allowed 96% of the samples to be sequenced. Thirty-five percent of the strains could be unambiguously identified to the species level based either on nuITS1 or nuITS2 sequences' using barcode gap calculations. nuITS2 Compensatory Base Change (CBC) and ITS1-5.8S-ITS2 region phylogenetic analysis, together with morphological inspection, confirmed the identification accuracy. In contrast, only 6% of the strains could be assigned to the correct species based solely on rbcL sequences. In conclusion, the data presented here indicates that either nuITS1 or nuITS2 are useful markers for DNA barcoding of freshwater green microalgae, with advantage for nuITS2 due to the larger availability of analytical tools and reference barcodes deposited at databases for this marker. PMID:26900844

  20. Adaptation of microalgae to a gradient of continuous petroleum contamination

    Energy Technology Data Exchange (ETDEWEB)

    Carrera-Martinez, Daniel; Mateos-Sanz, Aranzazu [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Lopez-Rodas, Victoria [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Costas, Eduardo, E-mail: ecostas@vet.ucm.es [AlgasGen Biotecnologia, EBT-UCM, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain); Genetica, Facultad de Veterinaria, Universidad Complutense de Madrid, Puerta de Hierro s/n, E-28040 Madrid (Spain)

    2011-01-25

    In order to study adaptation of microalgae to petroleum contamination, we have examined an environmental stress gradient by crude oil contamination in the Arroyo Minero River (AMR), Argentina. Underground crude oil has constantly leaked out since 1915 as a consequence of test drilling for possible petroleum exploitation. Numerous microalgae species proliferated in AMR upstream of the crude oil spill. In contrast, only four microalgal species were detected in the crude oil spill area. Species richness increases again downstream. Microalgae biomass in the crude oil spill area is dominated by a mesophile species, Scenedesmus sp. Effects of oil samples from AMR spill on photosynthetic performance and growth were studied using laboratory cultures of two Scenedesmus sp. strains. One strain (Se-co) was isolated from the crude oil spill area. The other strain (Se-pr) was isolated from a pristine area without petroleum contamination. Crude oil has undetectable effects on Se-co strain. In contrast crude oil rapidly destroys Se-pr strain. However, Se-pr strain can adapt to low doses of petroleum ({<=}3% v/v total hydrocarbons/water) by means of physiological acclimatization. In contrast, only rare crude oil-resistant mutants are able to grow under high levels of crude oil ({>=}10% v/v total hydrocarbons/water). These crude oil-resistant mutants have arisen through rare spontaneous mutations that occur prior to crude oil exposure. Species richness in different areas of AMR is closely connected to the kind of mechanism (genetic adaptation vs. physiological acclimatization) that allows adaptation. Resistant-mutants are enough to assure the survival of microalgal species under catastrophic crude oil spill.

  1. DNA Barcoding Green Microalgae Isolated from Neotropical Inland Waters.

    Directory of Open Access Journals (Sweden)

    Sámed I I A Hadi

    Full Text Available This study evaluated the feasibility of using the Ribulose Bisphosphate Carboxylase Large subunit gene (rbcL and the Internal Transcribed Spacers 1 and 2 of the nuclear rDNA (nuITS1 and nuITS2 markers for identifying a very diverse, albeit poorly known group, of green microalgae from neotropical inland waters. Fifty-one freshwater green microalgae strains isolated from Brazil, the largest biodiversity reservoir in the neotropics, were submitted to DNA barcoding. Currently available universal primers for ITS1-5.8S-ITS2 region amplification were sufficient to successfully amplify and sequence 47 (92% of the samples. On the other hand, new sets of primers had to be designed for rbcL, which allowed 96% of the samples to be sequenced. Thirty-five percent of the strains could be unambiguously identified to the species level based either on nuITS1 or nuITS2 sequences' using barcode gap calculations. nuITS2 Compensatory Base Change (CBC and ITS1-5.8S-ITS2 region phylogenetic analysis, together with morphological inspection, confirmed the identification accuracy. In contrast, only 6% of the strains could be assigned to the correct species based solely on rbcL sequences. In conclusion, the data presented here indicates that either nuITS1 or nuITS2 are useful markers for DNA barcoding of freshwater green microalgae, with advantage for nuITS2 due to the larger availability of analytical tools and reference barcodes deposited at databases for this marker.

  2. Carbon dioxide fixation by microalgae cultivated in open bioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Centeno da Rosa, Ana Priscila; Fernandes Carvalho, Lisiane; Goldbeck, Luzia [Laboratory of Biochemical Engineering, College of Chemistry and Food, Federal University of Rio Grande (FURG), P.O. Box 474, Rio Grande, RS 96201-900 (Brazil); Vieira Costa, Jorge Alberto, E-mail: dqmjorge@furg.br [Laboratory of Biochemical Engineering, College of Chemistry and Food, Federal University of Rio Grande (FURG), P.O. Box 474, Rio Grande, RS 96201-900 (Brazil)

    2011-08-15

    Highlights: {yields} We studied the growth and CO{sub 2} fixation by Spirulina LEB18 and Chlorella kessleri. {yields} The maximum dailyfixation was obtained for Spirulina with an injection of 6% of CO{sub 2}. {yields} The microalgae presented growth during the 20 d of culture with up to 18% of CO{sub 2}. {yields} The use of CO{sub 2} from industrial generation decreases the cost of producing biomass. - Abstract: The biofixation of carbon dioxide (CO{sub 2}) by microalgae has been proven to be an efficient and economical method, mainly due to the photosynthetic ability of these microorganisms to use this gas as a source of nutrients for their development. The aim of this work was to study the growth of Spirulina LEB18 and Chlorella kessleri microalgae, exposed to controlled and non-controlled conditions, with the injection of different concentrations of CO{sub 2}. The cultures was carried out in 6 L open raceway ponds, under controlled conditions at 30 {sup o}C and 39 {mu}E m{sup -2} s{sup -1} and under non-controlled conditions, protected by a tunnel of transparent film. The experiments were subjected to CO{sub 2} injections at concentrations of 0.038, 6, 12 and 18% (v/v). The highest concentration of biomass (4.95 g L{sup -1}) and maximum daily fixation (0.21 g g{sup -1} d{sup -1}) were obtained for Spirulina LEB18 in culture that was prepared in non-controlled conditions with an injection of 6% (v/v) of CO{sub 2}. C. kessleri had maximum (p < 0.0008) specific growth rate (0.84 d{sup -1}) when grown with 18% (v/v) of CO{sub 2} in non-controlled conditions of cultivation.

  3. Fuel options from microalgae with representative chemical compositions

    Energy Technology Data Exchange (ETDEWEB)

    Feinberg, D. A.

    1984-07-01

    Representative species of microalgae are examined with respect to their reported chemical compositions. Each species is analyzed under a variety of culture conditions, with the objective being to characterize an optimum mixture of fuel products (e.g., methane, ethanol, methylester) which should be produced by the particular species. Historically the emphasis has been on the entire algal cell mass. Using the reported chemical composition for the representative species under specific sets of growth conditions, some conclusions can be drawn about the preferred fuel product conversion routes that could be employed. 10 references, 7 figures, 12 tables.

  4. Compostos bioativos de microalgas com interesse no tratamento da diabetes

    OpenAIRE

    Gago, Alexandre da Silva

    2016-01-01

    Dissertação de Mestrado, Biologia Molecular e Microbiana, Faculdade de Ciências e Tecnologia, Universidade do Algarve, 2016 A diabetes é uma doença que afeta milhões de pessoas em todo o mundo e condiciona a qualidade de vida das mesmas. A diabetes tipo 2 tem merecido destaque pelo aumento da sua incidência e pelo facto de ser uma doença evitável. O tratamento atualmente resume-se a medicação específica juntamente com uma dieta bastante restritiva. As microalgas sendo conhecida...

  5. Invention of outdoor closed type photobioreactor for microalgae

    International Nuclear Information System (INIS)

    For efficient mass production of microalgae, we invented a novel photobioreactor that uses aeration for mixing. To select better chamber shapes for a photobioreactor, two aspects of its performance were numerically simulated, mixing and light reception. Two shapes survived the computational filters and were tested by cultivating Chlorococum littorale. One of them attained 20.5 g/m2/day in dry weight in the winter days in Japan. Recently, this figure was overwritten by the performance of 37.3 g/m2/day for Chaetoceros calcitrans with the maximum cell density of 2.5 g/L

  6. Potency of Microalgae as Biodiesel Source in Indonesia

    OpenAIRE

    H Hadiyanto; W Widayat; Andri Cahyo Kumoro

    2012-01-01

    Within 20 years, Indonesia should find another energy alternative to substitute current fossil oil. Current use of renewable energy is only 5% and need to be improved up to 17% of our energy mix program. Even though, most of the area in Indonesia is covered by sea, however the utilization of microalgae as biofuel production is still limited. The biodiesel from current sources (Jatropha, palm oil, and sorghum) is still not able to cover all the needs if the fossil oil cannot be explored anymor...

  7. Potential of microalgae and cyanobacteria in bioremediation of distillery wastewaters

    OpenAIRE

    Isis Amores-Sanchez; María del Carmen Terrón-Orellana; Aldo E. González-Becerra; Tania González-Díaz de Villegas

    2015-01-01

    Los efluentes de destilerías, también llamados vinazas, son unos de los residuales más agresivos para el medio ambiente. Muchos estudios han focalizado los biotratamientos al uso de hongos y bacterias, pero la descontaminación eficiente de dicho efluente es todavía un problema sin resolver. En los últimos tiempos microalgas y cianobacterias han surgido como una alternativa muy promisoria a la destoxificación. Estos microorganismo ofrecen una serie de ventajas como son: la degradación de gran ...

  8. Todo sobre el neobarroco

    Directory of Open Access Journals (Sweden)

    Arturo Carrera

    2007-07-01

    Full Text Available Lo que hemos escuchado y atendido hasta aquí, hoy, ayer, sobre todo en la propuesta poética esbozada por Sergio Raimondi en su ensayo sobre Aldo Oliva, demuestra que las singularidades, su pasión, anulan subrepticiamente las nominaciones.Anoche en la televisión una orquesta sinfónica y un coro numeroso. Súbitamente, me hubiera gustado ser uno de esos intérpretes solitarios para sí, a pesar de la armonía, anónimos, a pesar del brillo sonoro… un violín, un triángulo… apenas… tres grillos… como ...

  9. Inferencias sobre Grafos

    OpenAIRE

    Sira M. Allende; Carlos N. Bouza

    2002-01-01

    El estudio de un juego puede ser modelado asumiendo que solo algunas partidas son observadas. Entonces el árbol del juego debe ser estimado utilizando información muestral. Similarmente ocurre al obtener información sobre el comportamiento de las decisiones tomadas por individuos muestreados sobre un árbol de decisión teórico. Al considerar una medida de probabilidad que caracterice el comportamiento de redes aleatorias se puede obtener un estimado del árbol asociado. Este problema es el anal...

  10. Mitos sobre agroecologia.

    OpenAIRE

    Canuto, João Carlos

    2011-01-01

    O presente ensaio vem a discutir alguns aspectos do discurso sobre a Agroecologia, procurando evidenciar contradições do senso comum, advindas seja de parte da comunidade leiga, dos meios de comunicação ou da comunidade científica. Coloca em debate alguns mitos sobre os sistemas agroecológicos, tais como: que sejam tecnologicamente retrógrados, de baixa produtividade, exigentes em mão-de-obra, economicamente inviáveis e “puramente ideológicos”.

  11. Microalgae of the continental shelf off Paraná State, southeastern Brazil: a review of studies

    Directory of Open Access Journals (Sweden)

    Frederico P. Brandini

    1996-01-01

    Full Text Available The paper reviews the taxonomic and ecological works on marine microalgae (phytoplankton and microphytobenthos off Paraná State, Southeastern Brazil. Various studies refer to the taxonomy of benthic diatoms. Few descriptive field works in coastal and adjacent shelf waters contribute to the understanding of phytoplankton dynamics in coastal and shelf areas. Patterns of geographic distribution and changes in the phytoplankton community are described in relation to water masses and seasonal variations in the hydrographic regime. During summertime, when warm oligotrophic waters predominate over the shelf, the phytoplankton is nummerically dominated by small phytotlagellates, dinotlagellates, coccolithophorids and filaments of cyanobacteria. During wintertime, the abundance of micro-size diatoms over the shclf increase due to the dominance of cold nutrient-rich waters from the South Atlantic Central Water and wind-driven vertical circulation. The phytoplankton community off Paraná State may be classified into two categorics: the diatom-dominated coastal assemblage, mainly controlled by nutrient inputs from land drainage and ressuspension of bottom sediments, and the tlagellate-dominated shelf assemblage, more affectcd by the seasonality of local hydrographic regime.O trabalho é uma revisão dos estudos taxonômicos e ecológicos das microalgas (planctônicas e bentônicas realizados no Estado do Paraná. A maioria dos trabalhos sobre microfitobentos são de caráter taxonômico e, basicamente, referem-se à diatomáceas bênticas sobre macroalgas ou fundos lodosos e consolidados. Poucos trabalhos contribuiram para o estudo da dinâmica espaço-temporal do fitoplâncton em áreas costeiras e de plataforma. São descritos os padrões de distribuição geográfica e as mudanças sazonais na comunidade fitoplanctônica em relação ao regime hidrográfico. No verão, quando águas quentes oligotróficas predominam na superfície, o fitoplâncton

  12. Purification of microalgae from bacterial contamination using a disposable inertia-based microfluidic device

    Science.gov (United States)

    Godino, Neus; Jorde, Felix; Lawlor, Daryl; Jaeger, Magnus; Duschl, Claus

    2015-08-01

    Microalgae are a promising source of bioactive ingredients for the food, pharmaceutical and cosmetic industries. Every microalgae research group or production facility is facing one major problem regarding the potential contamination of the algal cell with bacteria. Prior to the storage of the microalgae in strain collections or to cultivation in bioreactors, it is necessary to carry out laborious purification procedures to separate the microalgae from the undesired bacterial cells. In this work, we present a disposable microfluidic cartridge for the high-throughput purification of microalgae samples based on inertial microfluidics. Some of the most relevant microalgae strains have a larger size than the relatively small, few micron bacterial cells, so making them distinguishable by size. The inertial microfluidic cartridge was fabricated with inexpensive materials, like pressure sensitive adhesive (PSA) and thin plastic layers, which were patterned using a simple cutting plotter. In spite of fabrication restrictions and the intrinsic difficulties of biological samples, the separation of microalgae from bacteria reached values in excess of 99%, previously only achieved using conventional high-end and high cost lithography methods. Moreover, due to the simple and high-throughput characteristic of the separation, it is possible to concatenate serial purification to exponentially decrease the absolute amount of bacteria in the final purified sample.

  13. Purification of microalgae from bacterial contamination using a disposable inertia-based microfluidic device

    International Nuclear Information System (INIS)

    Microalgae are a promising source of bioactive ingredients for the food, pharmaceutical and cosmetic industries. Every microalgae research group or production facility is facing one major problem regarding the potential contamination of the algal cell with bacteria. Prior to the storage of the microalgae in strain collections or to cultivation in bioreactors, it is necessary to carry out laborious purification procedures to separate the microalgae from the undesired bacterial cells. In this work, we present a disposable microfluidic cartridge for the high-throughput purification of microalgae samples based on inertial microfluidics. Some of the most relevant microalgae strains have a larger size than the relatively small, few micron bacterial cells, so making them distinguishable by size. The inertial microfluidic cartridge was fabricated with inexpensive materials, like pressure sensitive adhesive (PSA) and thin plastic layers, which were patterned using a simple cutting plotter. In spite of fabrication restrictions and the intrinsic difficulties of biological samples, the separation of microalgae from bacteria reached values in excess of 99%, previously only achieved using conventional high-end and high cost lithography methods. Moreover, due to the simple and high-throughput characteristic of the separation, it is possible to concatenate serial purification to exponentially decrease the absolute amount of bacteria in the final purified sample. (paper)

  14. Photosynthetic aeration in biological wastewater treatment using immobilized microalgae-bacteria symbiosis.

    Science.gov (United States)

    Praveen, Prashant; Loh, Kai-Chee

    2015-12-01

    Chlorella vulgaris encapsulated in alginate beads were added into a bioreactor treating synthetic wastewater using Pseudomonas putida. A symbiotic CO2/O2 gas exchange was established between the two microorganisms for photosynthetic aeration of wastewater. During batch operation, glucose removal efficiency in the bioreactor improved from 50% in 12 h without aeration to 100% in 6 h, when the bioreactor was aerated photosynthetically. During continuous operation, the bioreactor was operated at a low hydraulic retention time of 3.3 h at feed concentrations of 250 and 500 mg/L glucose. The removal efficiency at 500 mg/L increased from 73% without aeration to 100% in the presence of immobilized microalgae. The initial microalgae concentration was critical to achieve adequate aeration, and the removal rate increased with increasing microalgae concentration. The highest removal rate of 142 mg/L-h glucose was achieved at an initial microalgae concentration of 190 mg/L. Quantification of microalgae growth in the alginate beads indicated an exponential growth during symbiosis, indicating that the bioreactor performance was limited by oxygen production rates. Under symbiotic conditions, the chlorophyll content of the immobilized microalgae increased by more than 30%. These results indicate that immobilized microalgae in symbiosis with heterotrophic bacteria are promising in wastewater aeration.

  15. Evaluation of alternatives for microalgae oil extraction based on exergy analysis

    International Nuclear Information System (INIS)

    Highlights: ► Exergy analysis was used as decision-making tool for evaluation of microalgae oil extraction. ► A robust composition of Chlorella sp. biomass was modeled and used for simulation. ► Three solvent-based microalgae oil extraction methods at large scale were compared. ► Hexane based extraction presented the highest exergetic efficiency. -- Abstract: Several technologies for microalgae oil extraction are being evaluated in order to find the most adequate for large scale microalgae processing. In this work, exergy analysis was used as an instrument for screening three design alternatives for microalgae oil extraction in a large-scale process and as a decision-making tool for evaluation and selection of novel technologies from the energy point of view. Routes were simulated using dedicated industrial process simulation software, taking as feedstock a representative and robust modeled composition of Chlorella sp. microalgae biomass. Mass, energy and exergy balances were performed for each alternative, and physical and chemical exergies of streams and all specific microalgae constituents modeled were calculated with the help of the thermodynamic properties of biomass components and operating conditions of streams. Exergetic efficiencies, total process irreversibilities, energy consumption and exergy destruction were calculated for all solvent-based microalgae oil extraction pathways evaluated. It was shown that exergy analysis led to identify the hexane-based oil extraction (HBE) as the most adequate alternative of the routes assessed for scaling up from the energy point of view, presenting a maximum exergy efficiency of 51% and exergetic losses of 982,000 MJ considering a production of 104,000 t of microalgae oil per year.

  16. Ultrastructural and flow cytometric analyses of lipid accumulation in microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, J.A.; Hand, R.E. Jr.; Mann, R.C.

    1986-12-01

    Lipid accumulation in three species of microalgae was investigated with flow cytometry (FCM) and transmission electron microscopy (TEM). Previous studies using batch cultures of a algae have led to the assumption that lipid accumulation in microalgae is a gradual process requiring at least several days for completion. However, FCM reveals, through changes in the chlorophyll:lipid ratio, that the time span required for individual cells to change metabolic state is short. Simultaneous FCM measurements of chlorophyll and nile red (neutral lipid) fluorescence in individual cells of nitrogen-deficient Isochrysis populations revealed a bimodal population distribution as one stage in the lipid accumulation process. The fact that two discrete populations exist, with few cells in an intermediate stage, suggests rapid response to a liqid trigger. Interpretations of light and electron microscopic observations are consistent with this hypothesis. The time required for an entire population to achieve maximum lipid content is considerably longer than that required for a single cell, due to the variation in response time among cells. In this study high lipid cultures were sometimes obtained by using FCM to separate high lipid cells from the remainder of the population. FCM holds much promise for strain enhancement but considerable developmental work, directed at providing more consistent results, remains to be done. 8 refs., 35 figs.

  17. Challenges and opportunities for hydrogen production from microalgae.

    Science.gov (United States)

    Oey, Melanie; Sawyer, Anne Linda; Ross, Ian Lawrence; Hankamer, Ben

    2016-07-01

    The global population is predicted to increase from ~7.3 billion to over 9 billion people by 2050. Together with rising economic growth, this is forecast to result in a 50% increase in fuel demand, which will have to be met while reducing carbon dioxide (CO2 ) emissions by 50-80% to maintain social, political, energy and climate security. This tension between rising fuel demand and the requirement for rapid global decarbonization highlights the need to fast-track the coordinated development and deployment of efficient cost-effective renewable technologies for the production of CO2 neutral energy. Currently, only 20% of global energy is provided as electricity, while 80% is provided as fuel. Hydrogen (H2 ) is the most advanced CO2 -free fuel and provides a 'common' energy currency as it can be produced via a range of renewable technologies, including photovoltaic (PV), wind, wave and biological systems such as microalgae, to power the next generation of H2 fuel cells. Microalgae production systems for carbon-based fuel (oil and ethanol) are now at the demonstration scale. This review focuses on evaluating the potential of microalgal technologies for the commercial production of solar-driven H2 from water. It summarizes key global technology drivers, the potential and theoretical limits of microalgal H2 production systems, emerging strategies to engineer next-generation systems and how these fit into an evolving H2 economy. PMID:26801871

  18. Anaerobic Co-Digestion of the Microalgae Scenedesmus Sp.

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Suarez, J. L.; Carreras, N.

    2011-06-07

    Microalgae biomass has been widely studied for biogas production over the last years and results show that anaerobic digestion is often limited by the low C/N ratio of this type of biomass. Therefore, codigestion with substrates of high C/N ratio is necessary. The objectives of this study are to set up an experimental method that ease reproducibility and control of anaerobic digestion processes in laboratory conditions and to determine the biodegradability and biogas production potential of the co-digestion process of microalgae Scenedesmus sp. and energy crop Opuntia ficus indica (L.) Miller. Results obtained showed that higher C/N ratios are preferred in order to maximize methane production. Highest methane yield obtained was 0.252m3CH4/Kg VS and degradability expressed as percentage COD reduced is around 30% for the ideal mixture found, made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. A laboratory setup using MicroOxymax respirometer, after its adaptation to work under anaerobic conditions, can be used for the monitoring of anaerobic digestion processes. Scenedesmus sp. as sole substrate for anaerobic digestion does not give good results due to low C/N ratio. However, when codigesting it with O. ficus-indica methane production is satisfactory. Best mixture was made up of 75% O. ficus-indica and 25% Scenedesmus sp. in VS basis. (Author)

  19. Improving microalgae for biotechnology--From genetics to synthetic biology.

    Science.gov (United States)

    Hlavova, Monika; Turoczy, Zoltan; Bisova, Katerina

    2015-11-01

    Microalgae have traditionally been used in many biotechnological applications, where each new application required a different species or strain expressing the required properties; the challenge therefore is to isolate or develop, characterize and optimize species or strains that can express more than one specific property. In agriculture, breeding of natural variants has been successfully used for centuries to improve production traits in many existing plant and animal species. With the discovery of the concepts of classical genetics, these new ideas have been extensively used in selective breeding. However, many biotechnologically relevant algae do not possess the sexual characteristics required for traditional breeding/crossing, although they can be modified by chemical and physical mutagens. The resulting mutants are not considered as genetically modified organisms (GMOs) and their cultivation is therefore not limited by legislation. On the other hand, mutants prepared by random or specific insertion of foreign DNA are considered to be GMOs. This review will compare the effects of two genetic approaches on model algal species and will summarize their advantages in basic research. Furthermore, we will discuss the potential of mutagenesis to improve microalgae as a biotechnological resource, to accelerate the process from specific strain isolation to growth optimization, and discuss the production of new products. Finally, we will explore the potential of algae in synthetic biology.

  20. Cultivating Microalgae in Domestic Wastewater for Biodiesel Production

    Directory of Open Access Journals (Sweden)

    Soha S.M. MOSTAFA

    2012-02-01

    Full Text Available The objective of this study was to evaluate the growth of nine species of microalgae (green and blue green microalgae on domestic waste water samples obtained from Zenein Waste Water Treatment Plant (ZWWTP, Giza governorate, Egypt. The species were cultivated in different kind of waste water; before treatment; after sterilization; with nutrients with sterilization and with nutrients without sterilization. The experiment was conducted in triplicate and cultures were incubated at 25�1�C under continuous shaking (150 rpm and illumination (2000 Lux for 15 days. pH, electric conductivity (EC, optical density (OD , dry weight (DW, were done at the time of incubation and at the end of experiment, in addition to determine the percentage of lipid and biodiesel. The data revealed that, domestic waste water with nutrient media (T3 was promising for cultivation of five algal species when compared with conventional media, Moreover, domestic waste water after sterilization (T2 was selected media for cultivation of Oscillatoria sp and Phormedium sp. However, T1 media (waste water without treatment was the promising media for cultivation of Nostoc humifusum. The biodiesel produced from algal species cultivated in waste water media ranged from 3.8 to 11.80% when compared with the conventional method (3.90 to 12.52%. The results of this study suggest that growing algae in nutrient rich media offers a new option of applying algal process in ZWWTP to mange the nutrient load for growth and valuable biodiesel feedstock production.

  1. Heavy Metal Bioaccumulation and Toxicity with Special Reference to Microalgae

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key component of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Production of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmentalization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mechanisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.

  2. Screening of biomethane production potential from dominant microalgae.

    Science.gov (United States)

    Fermoso, Fernando G; Beltran, Carolina; Jimenez, Antonia; Fernández, María José; Rincón, Bárbara; Borja, Rafael; Jeison, David

    2016-10-14

    The use of microalgae for biomethane production has been considerably increasing during the recent years. In this study, four dominant species belonging to the genera Scenedesmus, Chlorella, Dunaliella and Nostoc were selected. The influence of different genera with several morphological, structural and physicochemical characteristics on methane production was assessed in biochemical methane potential (BMP) tests. The ultimate methane yield values were 332 ± 24, 211 ± 2, 63 ± 17 and 28 ± 10 mL CH4/g VSadded for Scenedesmus obliquus, Chlorella sorokiniana, Dunaliella salina and Nostoc sp., respectively. The highest methane production was achieved by microalga species that had no complex cell wall or wall basically composed by proteins and simple sugars such as in S. obliquus, whereas lower methane yields were found for D. salina and Nostoc sp., due to the salinity effects and cell wall composition in terms of complex polysaccharide and glycolipid layers, respectively. Kinetic constant values obtained in the BMP tests ranged between 1.00 ± 0.08 and 0.097 ± 0.005 days(-1) for D. salina and S. obliquus, respectively. PMID:27409043

  3. Micro-algae: French players discuss the matter

    International Nuclear Information System (INIS)

    About 75000 species of algae have been reported so far, the domains of application are huge and investment are increasing all around the world. One of the difficulties is to find the most appropriate algae to a specific application. Some development programs have failed scientifically or economically for instance the production of protein for animal food from the chlorella algae or the production of bio-fuel from C14-C18 chains, from zeaxanthine and from phycoerytrine. On the other side some research programs have led to promising industrial applications such as the production of food for fish and farm animals. Some research fields are completely innovative such as the use of micro-algae for the construction of bio-walls for buildings. Micro-algae are diverse and fragile. Photo-bioreactors have been designed to breed fragile algae like some types of chlorophycees used in bio-fuel and in cosmetics, a prototype has been tested for 15 months and its production is about 2 kg of dry matter a day. (A.C.)

  4. Thermochemical liquefaction characteristics of microalgae in sub- and supercritical ethanol

    Energy Technology Data Exchange (ETDEWEB)

    You, Qiao; Chen, Liang [College of Environmental Science and Engineering, Hunan University, Changsha (China); Key Laboratory of Environment Biology and Pollution Control, Ministry of Education, Changsha (China)

    2011-01-15

    Thermochemical liquefaction characteristics of Spirulina, a kind of high-protein microalgae, were investigated with the sub- and supercritical ethanol as solvent in a 1000 mL autoclave. The influences of various liquefaction parameters on the yields of products (bio-oil and residue) from the liquefaction of Spirulina were studied, such as the reaction temperature (T), the S/L ratio (R{sub 1}, solid: Spirulina, liquid: ethanol), the solvent filling ratio (R{sub 2}) and the type and dosage of catalyst. Without catalyst, the bio-oil yields were in the range of 35.4 wt.% and 45.3 wt.% depending on the changes of T, R{sub 1} and R{sub 2}. And the bio-oil yields increased generally with increasing T and R{sub 2}, while the bio-oil yields reduced with increasing R{sub 1}. The FeS catalyst was certified to be an ideal catalyst for the liquefaction of Spirulina microalgae for its advantages on promoting bio-oil production and suppressing the formation of residue. The optimal dosage of catalyst (FeS) was ranging from 5-7 wt.%. The elemental analyses and FT-IR and GC-MS measurements for the bio-oils revealed that the liquid products have much higher heating values than the crude Spirulina sample and fatty acid ethyl ester compounds were dominant in the bio-oils, irrespective of whether catalyst was used. (author)

  5. Optimization of process configuration and strain selection for microalgae-based biodiesel production.

    Science.gov (United States)

    Yu, Nan; Dieu, Linus Tao Jie; Harvey, Simon; Lee, Dong-Yup

    2015-10-01

    A mathematical model was developed for the design of microalgae-based biodiesel production system by systematically integrating all the production stages and strain properties. Through the hypothetical case study, the model suggested the most economical system configuration for the selected microalgae strains from the available processes at each stage, thus resulting in the cheapest biodiesel production cost, S$2.66/kg, which is still higher than the current diesel price (S$1.05/kg). Interestingly, the microalgae strain properties, such as lipid content, effective diameter and productivity, were found to be one of the major factors that significantly affect the production cost as well as system configuration.

  6. Hypocholesterolemic Effects of Nutraceuticals Produced from the Red Microalga Porphyridium sp. in Rats

    Directory of Open Access Journals (Sweden)

    Shoshana Malis Arad

    2009-11-01

    Full Text Available Red microalgae contain functional sulfated polysaccharides (containing dietary fibers, polyunsaturated fatty acids, zeaxanthin, vitamins, minerals, and proteins. Studies in rat models support the therapeutic properties of algal biomass and isolated polysaccharides. Algal products incorporated into rat diets were found to significantly improve total serum cholesterol, serum triglycerides, hepatic cholesterol levels, HDL/LDL ratios and increased fecal excretion of neutral sterols and bile acids. Morphological and metabolic changes were induced by consumption of algal products. These results suggest that red microalgae can be used as potent hypocholesterolemic agents, and they support the potential use of red microalgae as novel nutraceuticals.

  7. Evaluation of available saline water resources in New Mexico for the production of microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Lansford, R.; Hernandez, J.; Enis, P.; Truby, D.; Mapel, C.

    1990-08-01

    Researchers evaluated saline water resources in New Mexico for their suitability as sites for large-scale microalgae production facilities. Production of microalgae could provide a renewable source of fuel, chemicals, and food. In addition, making use of the unused saline water resources would increase the economic activity in the state. After analyzing the 15 billion acre-ft of unused saline water resources in the state, scientists narrowed the locations down to six sites with the most potential. With further analysis, they chose the Tularosa Basin in southern New Mexico as the best-suited area for 100-hectare microalgae production facility. 34 refs., 38 figs., 14 tabs.

  8. Use of Solid Waste from Thermoelectric Plants for the Cultivation of Microalgae

    Directory of Open Access Journals (Sweden)

    Bruna da Silva Vaz

    2016-01-01

    Full Text Available ABSTRACT The aim of this study was to analyze the influence of solid waste on the cultivation of the microalgae Spirulina sp. LEB 18 and Chlorella fusca LEB 111 with 0, 40, 80 and 120 ppm of mineral coal ash. The addition of the ash did not inhibit the cultivation of microalgae at the tested concentrations, showing that it could be used for the cultivation of these microalgae due to the minerals present in the ash, which might substitute the nutrients needed for their growth.

  9. Produção de biomassa e teores de carbono, hidrogênio, nitrogênio e proteína em microalgas Production of biomass and carbon, hydrogen, nitrogen and protein contents in microalgae

    Directory of Open Access Journals (Sweden)

    Silvana Ohse

    2009-09-01

    Full Text Available O aumento da emissão de CO2 e de outros gases efeito estufa tem gerado debates em nível mundial sobre alterações climáticas e estimulado o desenvolvimento de estratégias mitigadoras. Trabalhos nessa área incluem sequestro de CO2 por meio da produção de microalgas aquáticas. Por essa razão, desenvolveu-se um estudo visando determinar os teores de carbono, hidrogênio, nitrogênio e proteína e a produção de biomassa seca de nove espécies de microalgas marinhas (Nannochloropsis oculata, Thalassiosira pseudonana, Phaeodactylum tricornutum, Isochrysis galbana, Tetraselmis suecica, Tetraselmis chuii Chaetoceros muelleri, Thalassiosira fluviatilis e Isochrysis sp. e uma de água doce (Chlorella vulgaris, em cultivo autotrófico estacionário com objetivo de identificar as mais produtivas e com maior capacidade de fixação de carbono. O experimento foi desenvolvido em sala de cultivo, na Universidade Federal de Santa Catarina, com iluminação contínua e radiação em torno de 150µmol m-2 s-1, temperatura de 25±2°C, suplementação de ar constante, sendo utilizados erlenmeyers com 800mL de meio de cultura. O delineamento experimental foi de blocos casualizados no tempo com três repetições. As espécies C. vulgaris e T. suecica são menos produtivas. Quando se visa à suplementação alimentar, as espécies C. vulgaris e T. Chuii são consideradas interessantes, uma vez que apresentam altos teores de C, N, H e proteína. As espécies N. Oculata, T. pseudonana e C. vulgaris apresentam altos teores de C, demonstrando alta capacidade de fixação de carbono.The increase of CO2 emission and other gases greenhouse effect, caused global debates about climatic alterations and stimulated the development of mitigative strategies. Researches in this area includes CO2 kidnapping through the aquatic microalgae production. For this reason, a study was developed aiming to determine the production of dry biomass, carbon content, hydrogen

  10. Fundamentals in Microalgae Harvesting: From Flocculation to Self-attachment

    Science.gov (United States)

    Cui, Yan

    Microalgae are a very promising source of biodiesel and other renewable energy due to their fast grow rates, high lipid contents and tremendous potential for water conservation and CO2 biofixation. However, a bottleneck issue with algae biofuel manufacturing is the lack of cost-effective harvesting methods. This research focuses on the technologies for improved microalgae harvesting to enable commercially viable and environmentally friendly biodiesel production. The first objective of this study was to optimize flocculation of marine microalga Nannochloropsis oculata with metal salts, aluminum sulfate (A.S.) and ferric chloride (F.C.) via response surface methodology. It was found that there existed a positive stoichiometric relationship between the flocculant dose (FD) and the initial biomass concentration (IABC). Optimum flocculation conditions were predicted at IABC of 1.7 g/l, pH 8.3, and FD of 383.5 microM for A.S., and IABC of 2.2 g/l, pH 7.9, and FD of 438.1 microM for F.C., under which the predicted maximum harvested solid concentration of algae were 32.98 and 30.10 g/l by using A.S. and F.C., respectively. The second objective was to investigate the mechanism of microalgae flocculation with metal salts. The theory of Derjaguin, Landau, Verwey and Overbeek (DLVO) was applied to understand the flocculation mechanism of a freshwater alga Scenedesmus dimorphus and a marine alga Nannochloropsis oculata under various pH and aluminum sulphate ionic strengths. Effective flocculation was achieved as a result of charge neutralization and sweep flocculation. When low flocculant dosage (theory failed to explain the results since sweep flocculation was found to predominate at alum dose above 1 mM. Understanding of cell-to-cell interactions of microalgae offered possibilities in design of a novel semi-immobilized algal production and harvesting method, which exploited cell to substrata interactions instead of cell-to-cell interactions. In such method, a solid carrier

  11. Isolation and application of SOX and NOX resistant microalgae in biofixation of CO2 from thermoelectricity plants

    International Nuclear Information System (INIS)

    Highlights: → Microalgae can help reduce global warming. → Synechococcus nidulans and Chlorella vulgaris were isolated in a thermoelectric plant. → Microalgae were compared with Spirulina and Scenedesmus obliquus for CO2 fixation. → Microalgae were exposed to CO2, SO2 and NO, simulating a gas from coal combustion. → C. vulgaris and Spirulina sp. showed 13.43% of maximum daily fixation. - Abstract: Microalgae have been studied for their potential use in foodstuffs, agriculture, in the treatment of wastewater and, in particular, in the reduction of atmospheric carbon dioxide, the main cause of global warming. Thermoelectricity plants account for 22% of CO2 emitted into the atmosphere and native microalgae may be more tolerant to the gases emitted from burning fossil fuels. In the study presented here, microalgae were isolated from ponds next to a Thermoelectricity Plant, located in southern Brazil, and identified as Synechococcus nidulans and Chlorella vulgaris. The isolated microalgae were grown and compared with two different strains of microalgae, Spirulina sp. and Scenedesmus obliquus, for CO2 biofixation. The microalgae were exposed to 12% CO2, 60 ppm of SO2 and 100 ppm of NO, simulating a gas from coal combustion. The C. vulgaris had similar behavior to Spirulina sp., with 13.43% of maximum daily fixation. The microalgae with the greater fixing capacity were C. vulgaris and Spirulina sp. and these can be grown in electric power plants for CO2 biofixation of the coal combustion gas, which would help reduce global warming.

  12. Inferencias sobre Grafos

    Directory of Open Access Journals (Sweden)

    Sira M. Allende

    2002-05-01

    Full Text Available El estudio de un juego puede ser modelado asumiendo que solo algunas partidas son observadas. Entonces el árbol del juego debe ser estimado utilizando información muestral. Similarmente ocurre al obtener información sobre el comportamiento de las decisiones tomadas por individuos muestreados sobre un árbol de decisión teórico. Al considerar una medida de probabilidad que caracterice el comportamiento de redes aleatorias se puede obtener un estimado del árbol asociado. Este problema es el analizado en este trabajo. Algunos resultados experimentales obtenidos usando Recocido Simulado ilustran el procedimiento. Su papel en el estudio de modelos económicos y de mercadeo es discutido.

  13. ASI: Dunaliella Marine Microalgae to Drop-In Replacement Liquid Transportation Fuel

    Science.gov (United States)

    Microalgae are a promising biofuels feedstock, theoretically yielding concentrations of triacylglycerides (TAGs) per unit area far higher than traditional feedstocks due to their rapid growth. Dunaliella is particularly advantageous as a feedstock because it is currently commercially mass cultured,...

  14. RECOLONIZATION OF SEDIMENT-ASSOCIATED MICROALGAE AND EFFECTS OF ESTUARINE INFAUNA ON MICROALGAL PRODUCTION

    Science.gov (United States)

    Experiments were performed to determine the rate of recolonization of sediment-associated microalgae and effects of infauna on microalgal biomass and production. Estuarine sediment was defaunated and transplanted to the field and the laboratory. Recolonization of sediment by flor...

  15. Comparative toxicity of water soluble fractions of four oils on the growth of a Microalga

    Digital Repository Service at National Institute of Oceanography (India)

    Phatarpekar, P.V.; Ansari, Z.A.

    Toxic effects of water soluble fractions (WSF) of four different fuel oils on a microalga. Tetraselmis gracilis, were examined and compared. On applying different concentrations of WSF, a decrease in cell population was observed. Depending...

  16. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock.

    Science.gov (United States)

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-01-01

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel. PMID:27618070

  17. Influences of Natural Colloid in Seawater on the Growth of a Microalga

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Colloid concentrates were obtained by employing a cross-flow filtration system to ultrafiltrate seawater(which was pre-filtrated by 0.45 μm acetate cellulose membrane) sucessively with three membranes.The retentions (colloid concentrates) and control sample(in which colloid was removed)were then inoculated with a microalga and cultivated in vitro.After continuously monitoring cell content during cultivation,it was found that colloid had an obvious beneficial effect on the growth of microalga.Although colloids with different sizes influenced microalga's growth in different extent and ways,a brief conclusion could be draw from experiments that colloid might be a potential nutrition source for microalga's growth.

  18. A Saponification Method for Chlorophyll Removal from Microalgae Biomass as Oil Feedstock.

    Science.gov (United States)

    Li, Tao; Xu, Jin; Wu, Hualian; Wang, Guanghua; Dai, Shikun; Fan, Jiewei; He, Hui; Xiang, Wenzhou

    2016-09-07

    Microalgae oil is an optimal feedstock for nutraceutical, pharmaceutical and biodiesel production, but its high levels of chlorophyll limit its large-scale application. To date, few effective approaches have been developed to remove chlorophyll from microalgae oil. The main purpose of this study was to present a preprocessing method of algae oil feedstock (Scenedesmus) to remove chlorophyll by saponification. The results showed that 96% of chlorophyll in biomass was removed. High quality orange transparent oil could be extracted from the chlorophyll reduced biomass. Specifically, the proportion of neutral lipids and saturation levels of fatty acids increased, and the pigments composition became carotenoids-based. The critical parameters of chlorophyll reduced biodiesel conformed to the standards of the USA, China and EU. Sodium copper chlorophyllin could be prepared from the bleaching effluent. The results presented herein offer a useful pathway to improve the quality of microalgae oil and reduce the cost of microalgae biodiesel.

  19. Estudios sobre Borges

    OpenAIRE

    Facultad de Humanidades y Ciencias de la Educación

    1991-01-01

    Contenidos de la obra: De Barthes a Pierre Menard | José Luis De Diego Pierre Menard, autor del Quijote: De la poligrafía al fraude | Andrea Cucatto Homenaje a Roberto Arlt: La otra cara de la moneda | Fabio Espósito Emma a través del espejo: Una lectura de Emma Zunz | Graciela Beatriz Goldchluk Sobre el concepto de verdad en Borges | Sergio Pastormerlo

  20. Isolation, Characterization and Identification of Microalgae from the Red Sea

    KAUST Repository

    Luque Alanís, Patricio

    2013-05-01

    Eukaryotic microalgae from the Red Sea were isolated, characterized and identified with the purpose of building a culture collection that will serve future research activities in the area of industrial microbiology. Seven sampling locations were surveyed using an in-house designed isolation protocol. Microalgae enrichment was carried out in vitro using the streak plate method and fluorescence activated cell sorting approaches. Colonial and cellular microscopy, growth media preference assays, as well as temperature, pH and salinity tolerance tests were carried out to describe the isolates. DNA extraction, PCR amplification, template sequencing and in silico analyses were carried out to identify the isolates and arrange them in a proper phylogenetic description. In total, 129 isolates were obtained. From these, only 39 were selected for characterization given their increased ability of accumulating large amounts of biomass in solid and liquid media in relatively short periods of time. All of these have a green color, are unicellular, non-motile, photosynthetic organisms and have a cell size ranging from 5 to 8 µm. More than half of them showed growth preference in Walne media, followed by F/2, MN and BG-11 SW. Maximum temperature tolerance of all organisms was around 38 ºC, while optimum growth was observed close to 25 ºC. pH preference was diverse and three groups were identified: acidic (6), intermediate (8 - 9) and alkaline (> 10) growing isolates. Salinity tests showed an overall growth preference at 25 PSU, approximately 10 units lower than that found at the sampling stations. Most isolates showed diminished growth at high salinity and high pH, except for OS3S1b which grew well in both cases, and could be an interesting strain to study further. Twenty four isolates were related to Ulvophyceae sp. MBIC10591 by BLAST approaches with a maximum identity of 96 - 97%. A maximum likelihood phylogenetic tree was created for these isolates, relative to the BLAST hits

  1. Using Benthic microalgae to asses groundwater ecological status

    International Nuclear Information System (INIS)

    The water resources have been evaluated for a long time by physicochemical parameters. These provide timely results and do not reveal much about the evolution of a pollutant load and resilient and buffering capacity of aquatic ecosystems. Techniques based on the evaluation of sensitivity index of living organisms in the presence of different impacts have been developed as an alternative to these procedures. Biological indicator species are unique environmental indicators as they offer a signal of the biological condition in a watershed. The use of bio indicators as an early warning of pollution or degradation in an ecosystem can help sustain critical resources. While indicator species is a term that is often used, it is somewhat inaccurate. Indicators are actually groups or types of biological resources that can be used to assess environmental condition. Within each group, individual species can be used to calculate metrics in an effort to assess water quality conditions. Aquatic invertebrates and microalgae are the two groups recommended in evaluations of water quality, both are required by DMA 2000. The aim of this study was to evaluate two water bodies to choose the most appropriate group of microalgae to use as a biological indicator and establish the proposed rates that adjust better to describe the ecological quality of waters in the ecoregions where are the sites of CNEA. Surveys were carried out for this recognition of environments in the Ezeiza Atomic Center (CAE) and the industrial mining complex Los Gigantes, phytobenthos samples were taken in three sites in the Ezeiza Atomic Center (CAE) and the industrial mining complex Los Gigantes, Cordoba. Water samples were collected for later determination of chlorophyll content and biomass estimation. Determination of microalgal species were carried out and established those most representative groups. From that observation diatoms were selected as best represented in both sites. Some of the genera found in the

  2. Pilot scale harvesting, separation and drying of microalgae biomass from compact photo-bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Alberto Tadeu Martins; Luz Junior, Luiz Fernando de Lima [Dept. de Engenharia Quimica. Universidade Federal do Parana, Curitiba, PR (Brazil)], e-mail: luzjr@ufpr.br; Mariano, Andre Bellin; Ghidini, Luiz Francisco Correa; Gnoatto, Victor Eduardo; Locatelli Junior, Vilson; Mello, Thiago Carvalho de; Vargas, Jose Viriato Coelho [Nucleo de Pesquisa e Desenvolvimento em Energia Autossustentavel (NPDEAS). Dept. de Engenharia Mecanica. Universidade Federal do Parana, Curitiba (Brazil)], E-mail: jvargas@demec.ufpr.br

    2010-07-01

    Bio diesel produced from microalgae lipids is gaining a substantial ground in the search for renewable energy sources. In order to optimize the operating conditions of a continuous process, several experiments were realized, both in laboratory and pilot scale. The microalgae cultivation can be conducted in a photo-bioreactor, a closed system which allows parameters control and necessarily involves the aquatic environment. Because of that, the use of separation unit operations is required. The process starts in a proposed compact photo-bioreactor, which consist of a chain of transparent tubes with 6 cm of diameter arranged in parallel where the cultivation media circulate with the help of a pump. This arrangement offers a closed culture with less risk of contamination and maintains a minimum contact with the environment. The microalgae grow inside the pipes under incidence of ambient light. In this paper, harvesting, separation and drying were studied, as part of the processes of a sustainable energy plant under construction at UFPR, as shown in Fig. 1. To control the production in a photo-bioreactor in continuous system, it is necessary to monitor the concentration of microalgae growth in suspension. To measure the cell concentration in this equipment, an optic sensor has been developed. The microalgae biomass separation from the culture media is achieved by microalgae flocculation. Several cultivation situations have been tested with different NaOH concentrations, increasing the pH to 10. The system was kept under agitation during the addition by an air pump into the tank. Thereafter the system was maintained static. After a short time, it was observed that the microalgae coagulated and settled. The clarified part water was removed, remaining a concentrated microalgae suspension. Our results suggest that pH increase is a suitable methodology for microalgae separation from the growth suspension. The microalgae sedimentation time was recorded, which allowed the

  3. Enzyme-Assisted Extraction of Oil from Wet Microalgae Scenedesmus sp. G4

    OpenAIRE

    Shuhao Huo; Zhongming Wang; Fengjie Cui; Bin Zou; Pengxiang Zhao; Zhenhong Yuan

    2015-01-01

    The enzyme-assisted aqueous extraction of oil from wet microalgae was employed to avoid the energy consumption of a dewatering process. In this paper, oil-rich microalgae Scenedesmus sp. G4 was hydrolyzed by enzyme mixtures for oil extraction. The results showed that the algae concentration had the greatest influence on yield of extracted oil, and the temperature and the ratio of enzyme mixtures affected the results as follows: the maximum yield of oil extracted from Scenedesmus sp. G4 reache...

  4. Genetic Engineering: A Promising Tool to Engender Physiological, Biochemical, and Molecular Stress Resilience in Green Microalgae

    OpenAIRE

    Guihéneuf, Freddy; Khan, Asif; Tran, Lam-Son P.

    2016-01-01

    As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest toward a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy ...

  5. Genetic engineering: a promising tool to engender physiological, biochemical and molecular stress resilience in green microalgae

    OpenAIRE

    Freddy eGuiheneuf; Asif eKhan; Lam-Son ePhan Tran

    2016-01-01

    As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest towards a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy...

  6. Pre-concentration strategies for microalgae harvesting as biorefinery process chain

    OpenAIRE

    Sirin, Sema

    2013-01-01

    Over the past few decades, microalgae become focus of the researches again as a possible raw material for the production of biodiesel due to the myth of the oil crisis and also Kyoto Protocol which entered into force in 2005. Although microalgae have proven to be very efficient at producing oil-rich lipids, the optimum conditions for algae cultivation and methods for harvesting and oil extraction have not been determined in details yet. In particular, the harvesting process is especially ...

  7. Sustainable hydrogen photoproduction by phosphorus-deprived marine green microalgae Chlorella sp.

    Science.gov (United States)

    Batyrova, Khorcheska; Gavrisheva, Anastasia; Ivanova, Elena; Liu, Jianguo; Tsygankov, Anatoly

    2015-01-01

    Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S), sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P) conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5-1.8 mg Chl·L-1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture. PMID:25629229

  8. Combining urban wastewater treatment with biohydrogen production: An integrated microalgae-based approach

    OpenAIRE

    Batista, Ana Paula; Ambrosano, Lucas; Graça, Sofia; Sousa, Catarina; Marques, Paula Alexandra; Ribeiro, Belina; Botrel, Elberis P.; Neto, Pedro Castro; de Gouveia, L.

    2015-01-01

    The aim of the present work was the simultaneous treatment of urban wastewater using microalgae and the energetic valorization of the obtained biomass. Chlorella vulgaris (Cv), Scenedesmus obliquus (Sc) and a naturally occurring algal Consortium C (ConsC) were grown in an urban wastewater. The nutrient removals were quite high and the treated water fits the legislation (PT Dec-Lei 236/98) in what concerns the parameters analysed (N, P, COD). After nutrient depletion the microalgae remained tw...

  9. Sustainable Hydrogen Photoproduction by Phosphorus-Deprived Marine Green Microalgae Chlorella sp.

    Directory of Open Access Journals (Sweden)

    Khorcheska Batyrova

    2015-01-01

    Full Text Available Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S, sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5–1.8 mg Chl·L−1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture.

  10. Potentials of converting microalgae into brine shrimp Artemia

    OpenAIRE

    Sorgeloos, P

    1985-01-01

    High densities of brine shrimp Artemia can be cultured in flow-through systems using the effluent of microalgae cultures as a combined source of culture medium and food. It has been proven at the "St. Croix Artificial Upwelling Mariculture Project" that in comparison with the fast growing clam Tapes japonica, brine shrimp assure a much more efficient conversion of plant into animal biomass. It appears from the given examples that microalgae conversion into brine shrimp Artemia offers efficien...

  11. Current status and outlook in the application of microalgae in biodiesel production and environmental protection

    OpenAIRE

    Xin eZhang; Junfeng eRong; Hui eChen; Chenliu eHe; Qiang eWang

    2014-01-01

    Microalgae have been currently recognized as one group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO2 fixation, NOX and wastewater treatment) and biorefinery have been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy ...

  12. Feasibility of Steam Hydrogasification of Microalgae for Production of Synthetic Fuels

    OpenAIRE

    Suemanotham, Amornrat

    2014-01-01

    The development of sustainable fuels from biomass has become important due to the depletion of fossil fuels and concerns of global climate change. Microalgae offer several advantages as sources for bioenergy; their rapid growth rate, high productivity and lipid content, ability to cultivate in places other than on farmlands, or arable land, and their ability to capture CO2 from flue gas which can be used as a source for photosynthesis. Microalgae are able to produce a wide range of biofuels ...

  13. Current Status and Outlook in the Application of Microalgae in Biodiesel Production and Environmental Protection

    OpenAIRE

    Zhang, Xin; Rong, Junfeng; Chen, Hui; He, Chenliu; Wang, Qiang

    2014-01-01

    Microalgae have been currently recognized as a group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids, and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO2 fixation, NOx, and wastewater treatment) and biorefinery has been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy b...

  14. Bio-gasification of post transesterified microalgae residues: A route to improving overall process renewabilities

    OpenAIRE

    Ehimen, Ehiazesebhor Augustine

    2012-01-01

    Using results from experiments and process modelling tools, a renewability assessment was carried out for the use of the conventional and in-situ transesterification processes for a large scale microalgae biodiesel production. In a present day scenario, all the transesterification processes were shown to be non-renewable. The process renewability of biodiesel production from microalgae was found to significantly improve with the use of renewable electricity, reacting alcohols from biomass fer...

  15. Chlorella protothecoides Microalgae as an Alternative Fuel for Tractor Diesel Engines

    OpenAIRE

    Saddam H. Al-lwayzy; Talal Yusaf

    2013-01-01

    Biodiesel has attracted a great deal attention recently as an alternative fuel due to increasing fuel prices and the imperative to reduce emissions. Among a wide range of biodiesel resources, microalgae are a promising alternative fuel source because of the high biomass, lipid productivity and environmentally friendliness. Microalgae is also a non-edible food, therefore, there will be no impact on the human food supply chain. In this work, petroleum diesel (PD) and biodiesel from the microalg...

  16. Biodiesel Production from Selected Microalgae Strains and Determination of its Properties and Combustion Specific Characteristics

    OpenAIRE

    N. Kokkinos; A. Lazaridou; N. STAMATIS; S. ORFANIDIS; A. Ch. Mitropoulos; A. Christoforidis; N. Nikolaou

    2015-01-01

    Biofuels are gaining importance as significant substitutes for the depleting fossil fuels. Recent focus is on microalgae as the third generation feedstock. In the present research work, two indigenous fresh water and two marine Chlorophyte strains have been cultivated successfully under laboratory conditions using commercial fertilizer (Nutrileaf 30-10-10, initial concentration=70 g/m3 ) as nutrient source. Gas chromatographic analysis data showed that microalgae biodiesel obta...

  17. Sustainability Evaluation of Biodiesel Produced from Microalgae Chlamydomonas sp Grown in Brewery Wastewater

    OpenAIRE

    Mata, Teresa M.; Santos, Janaína; Mendes, Adélio M; Caetano, Nídia S.; Martins, António A.

    2014-01-01

    This study performs a sustainability evaluation of biodiesel from microalga Chlamydomonas sp. grown in 20 % (v/v) of brewery’s wastewater, blended with pentose sugars (xylose, arabinose or ribose resulting from the hydrolysis of brewer’s spent grains (BSG). The life cycle steps considered for the study are: microalgae cultivation, biomass processing and lipids extraction at the brewery site, and its conversion to biodiesel at a dedicated external biofuel’s plant. Three sustainabil...

  18. Recent developments in the commercial production of DHA and EPA rich oils from micro-algae

    OpenAIRE

    Winwood Robert J.

    2013-01-01

    The regular intake of marine omega 3’s DHA and EPA has been scientifically established as providing a wide range of health benefits. This paper reviews recent developments in the commercial production of DHA and EPA rich oils from micro-algae. The selection of suitable micro-algae species is discussed. The complexities of producing algal oil rich in marine omega 3’s is examined in terms of both upstream and downstream production.

  19. Cultivation of microalgae: effect of light/dark cycles on biomass yield

    OpenAIRE

    Janssen, M.G.J.

    2002-01-01

    In this thesis the efficiency of light utilization of microalgae was studied under light/dark cycles encountered in photobioreactors. Phototrophic microorganisms such as microalgae and cyanobacteria could provide valuable compounds. For many of these applications it is essential to use enclosed photobioreactors in which monocultures can be maintained for an extended time. Because light energy is the growth limiting substrate, light supply plays a key role in photobioreactor design.The light r...

  20. Antioxidant potential of microalgae in relation to their phenolic and carotenoid content

    OpenAIRE

    Goiris, Koen; Muylaert, Koenraad; Fraeye, Ilse; Foubert, Imogen; De Brabanter, Joseph; De Cooman, Luc

    2012-01-01

    In the past decades, food scientists have been searching for natural alternatives to replace synthetic antioxidants. In order to evaluate the potential of microalgae as new source of safe antioxidants, 32 microalgal biomass samples were screened for their antioxidant capacity using three antioxidant assays, and both total phenolic content and carotenoid content were measured. Microalgae were extracted using a one-step extraction with ethanol/water, and alternatively, a three-step fractionatio...

  1. Microalgae biomass as fermentation substrate for hydrogen and butyric acid production by clostridium tyrobutyricum

    OpenAIRE

    Ortigueira, J.; Lúcio, M.; S. Rodrigues; Alves, Luís Manuel; L. de Gouveia; Moura, Patrícia

    2012-01-01

    Fossil fuels are a limited type of feedstock, increasingly expensive, and carrying strong polluting properties. The search for alternative sources which can replace fossil fuels without the severe disadvantages that its use conveys is therefore of paramount importance. Microalgae biomass represents an example of such non-food renewable biomass that can be regarded as a valid alternative to fossil fuels. As biomass, microalgae are highly desirable since they are photosynthetic organisms with a...

  2. Micro-algae come of age as a platform for recombinant protein production

    OpenAIRE

    Specht, Elizabeth; Miyake-Stoner, Shigeki; Mayfield, Stephen

    2010-01-01

    A complete set of genetic tools is still being developed for the micro-alga Chlamydomonas reinhardtii. Yet even with this incomplete set, this photosynthetic single-celled plant has demonstrated significant promise as a platform for recombinant protein expression. In recent years, techniques have been developed that allow for robust expression of genes from both the nuclear and plastid genome. With these advances, many research groups have examined the pliability of this and other micro-algae...

  3. Manipulating Fatty Acid Biosynthesis in Microalgae for Biofuel through Protein-Protein Interactions

    OpenAIRE

    Jillian L Blatti; Joris Beld; Behnke, Craig A; Michael Mendez; Mayfield, Stephen P; Burkart, Michael D.

    2012-01-01

    Microalgae are a promising feedstock for renewable fuels, and algal metabolic engineering can lead to crop improvement, thus accelerating the development of commercially viable biodiesel production from algae biomass. We demonstrate that protein-protein interactions between the fatty acid acyl carrier protein (ACP) and thioesterase (TE) govern fatty acid hydrolysis within the algal chloroplast. Using green microalga Chlamydomonas reinhardtii (Cr) as a model, a structural simulation of docking...

  4. Phenotypic evolution in microalgae: a dramatic morphological shift in Dictyosphaerium chlorelloides (Chlorophyta) after exposure to TNT

    OpenAIRE

    Costas, Eduardo; López Rodas, Victoria; García-Villada, Libertad; Flores-Moya, Antonio

    2006-01-01

    Phenotypic evolution in microalgae: a dramatic morphological shift in Dictyosphaerium chlorelloides (Chlorophyta) after exposure to TNT. The occurrence of rapid morphological evolution in the microalga Dictyosphaerium chlorelloides (Chlorophyta) was induced after exposure of the wild strains of the alga to the potent algal poison 2,4,6-trinitrotoluene (TNT). After exposing a wildtype population (consisted of representative spherical-ellipsoidal cells) to doses of TNT that were lethal for most...

  5. A comparative study of bio-oils from pyrolysis of microalgae and oil seed waste in a fluidized bed.

    Science.gov (United States)

    Kim, Sung Won; Koo, Bon Seok; Lee, Dong Hyun

    2014-06-01

    The pyrolysis of Scenedesmus sp. and Jatropha seedshell cake (JSC) was investigated under similar operating condition in a fluidized bed reactor for comparison of pyrolytic behaviors from different species of lipids-containing biomass. Microalgae showed a narrower main peak in differential thermogravimetric curve compared to JSC due to different constituents. Pyrolysis liquid yields were similar; liquid's oil proportion of microalgae is higher than JSC. Microalgae bio-oil was characterized by similar carbon and hydrogen contents and higher H/C and O/C molar ratios compared to JSC due to compositional difference. The pyrolytic oils from microalgae and JSC contained more oxygen and nitrogen and less sulfur than petroleum and palm oils. The pyrolytic oils showed high yields of fatty oxygenates and nitrogenous compounds. The microalgae bio-oil features in high concentrations of aliphatic compounds, fatty acid alkyl ester, alcohols and nitriles. Microalgae showed potentials for alternative feedstock for green diesel, and commodity and valuable chemicals. PMID:24747387

  6. Growth inhibition to three red tide microalgae by extracts of Ulva pertusa

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Growth inhibition effect of different concentration of distilled water extract and four polar organic solvent (methanol, acetone, ether and chloroform) extracts of Ulva pertusa on three typical red tide microalgae (Heterosigma akashiwo, Alexandrium tamarense and Prorocentrum micans) were investigated. Liquid-liquid fractionation and HPLC analysis for methanol extract of U. pertusa were carried out.Growth of the three microalgae was significantly inhibited by the distilled water extract of U. pertusa at relatively higher concentration. However, the cells of the three microalgae did not die completely even at high concentration. Methanol extract of U. pertusa showed the highest growth inhibition on the three microalgae, and all the cells of the three microalgae were killed at relatively high concentration. The other three organic solvent extracts of U. pertusa had no apparent effect on the three microalgae. The results of bioassays and HPLC analysis suggested that the inhibitory substances in U. pertusa to the microalgal growth had relatively high polarities. H. akashiwo was the most sensitive one while A. tamarense was the most tolerant one to the growth inhibitory substances.

  7. Antioxidant activity of some Moroccan marine microalgae: Pufa profiles, carotenoids and phenolic content.

    Science.gov (United States)

    Maadane, Amal; Merghoub, Nawal; Ainane, Tarik; El Arroussi, Hicham; Benhima, Redouane; Amzazi, Saaid; Bakri, Youssef; Wahby, Imane

    2015-12-10

    In order to promote Moroccan natural resources, this study aims to evaluate the potential of microalgae isolated from Moroccan coastlines, as new source of natural antioxidants. Different extracts (ethanolic, ethanol/water and aqueous) obtained from 9 microalgae strains were screened for their in vitro antioxidant activity using DPPH free radical-scavenging assay. The highest antioxidant potentials were obtained in Dunalliela sp., Tetraselmis sp. and Nannochloropsis gaditana extracts. The obtained results indicate that ethanol extract of all microalgae strains exhibit higher antioxidant activity, when compared to water and ethanol/water extracts. Therefore, total phenolic and carotenoid content measurement were performed in active ethanol extracts. The PUFA profiles of ethanol extracts were also determined by GC/MS analysis. The studied microalgae strains displayed high PUFA content ranging from 12.9 to 76.9 %, total carotenoids content varied from 1.9 and 10.8mg/g of extract and total polyphenol content varied from 8.1 to 32.0mg Gallic acid Equivalent/g of extract weight. The correlation between the antioxidant capacities and the phenolic content and the carotenoids content were found to be insignificant, indicating that these compounds might not be major contributor to the antioxidant activity of these microalgae. The microalgae extracts exerting the high antioxidant activity are potential new source of natural antioxidants.

  8. Microalgae biofuels: A critical review of issues, problems and the way forward.

    Science.gov (United States)

    Lam, Man Kee; Lee, Keat Teong

    2012-01-01

    Culturing of microalgae as an alternative feedstock for biofuel production has received a lot of attention in recent years due to their fast growth rate and ability to accumulate high quantity of lipid and carbohydrate inside their cells for biodiesel and bioethanol production, respectively. In addition, this superior feedstock offers several environmental benefits, such as effective land utilization, CO(2) sequestration, self-purification if coupled with wastewater treatment and does not trigger food versus fuel feud. Despite having all these 'theoretical' advantages, review on problems and issues related to energy balance in microalgae biofuel are not clearly addressed until now. Base on the maturity of current technology, the true potential of microalgae biofuel towards energy security and its feasibility for commercialization are still questionable. Thus, this review is aimed to depict the practical problems that are facing the microalgae biofuel industry, covering upstream to downstream activities by accessing the latest research reports and critical data analysis. Apart from that, several interlink solutions to the problems will be suggested with the purpose to bring current microalgae biofuel research into a new dimension and consequently, to revolutionize the entire microalgae biofuel industry towards long-term sustainability. PMID:22166620

  9. The potential of transgenic green microalgae; a robust photobioreactor to produce recombinant therapeutic proteins.

    Science.gov (United States)

    Akbari, Fariba; Eskandani, Morteza; Khosroushahi, Ahmad Yari

    2014-11-01

    Microalgae have been used in food, cosmetic, and biofuel industries as a natural source of lipids, vitamins, pigments and antioxidants for a long time. Green microalgae, as potent photobioreactors, can be considered as an economical expression system to produce recombinant therapeutical proteins at large-scale due to low cost of production and scaling-up capitalization owning to the inexpensive medium requirement, fast growth rate, and the ease of manipulation. These microalgae possess all benefit eukaryotic expression systems including the ability of post-translational modifications required for proper folding and stability of active proteins. Among the many items regarded as recombinant protein production, this review compares the different expression systems with green microalgae like Dunaliella by viewing the nuclear/chloroplast transformation challenges/benefits, related selection markers/reporter genes, and crucial factors/strategies affecting the increase of foreign protein expression in microalgae transformants. Some important factors were discussed regarding the increase of protein yielding in microalgae transformants including: transformation-associated genotypic modifications, endogenous regulatory factors, promoters, codon optimization, enhancer elements, and milking of recombinant protein.

  10. Enzyme-assisted aqueous extraction of lipid from microalgae.

    Science.gov (United States)

    Liang, Kehong; Zhang, Qinghua; Cong, Wei

    2012-11-28

    An improved lipid extraction process has been established for microalgal using enzyme-assisted aqueous extraction processing (EAEP), which mainly involved in sonication and enzyme treatment. As compared to cellulase, neutral protease and alkaline protease, significantly higher lipid recovery was achieved by snailase and trypsin. The highest lipid recovery of 49.82% was obtained by a combined sonication-enzyme treatment at pH 4. The enhancement mechanism of the EAEP was analyzed in terms of the particle size of cream and zeta potential. In addition, microalgal lipid recovery was also affected by lipid class composition and the type of algae. The present study demonstrates a promising alternative to conventional lipid extraction of microalgae and the quantitative information on EAEP of oleaginous alga can provide valuable data for process design at pilot and industrial scale.

  11. A solar photobioreactor for the production of biohydrogen from microalgae

    Science.gov (United States)

    Panti, Luis; Chávez, Pedro; Robledo, Daniel; Patiño, Rodrigo

    2007-09-01

    The green microalga Chlamydomonas reinhardtii is proposed to produce hydrogen in a low-cost system using the solar radiation in Yucatan, Mexico. A two-step process is necessary with a closed photobioreactor, in which the algae are firstly growth and then induced for hydrogen generation. Preliminary results are presented in this work with some planning for the future. Different culture broths, temperatures and light intensities were tested for biomass and hydrogen production in laboratory conditions. The first experiments in external conditions with solar radiation and without temperature control have been performed, showing the potential of this technique at larger scales. However, some additional work must be done in order to optimize the culture maintenance, particularly in relation with the temperature control, the light radiation and the carbon dioxide supply, with the idea of keeping an economic production.

  12. Applications of Diatoms as Potential Microalgae in Nanobiotechnology

    Directory of Open Access Journals (Sweden)

    Ahmad Yari Khosroushahi

    2012-05-01

    Full Text Available Introduction: Diatoms are single cell eukaryotic microalgae, which present in nearly every water habitat make them ideal tools for a wide range of applications such as oil explora­tion, forensic examination, environmental indication, biosilica pattern generation, toxicity testing and eutrophication of aqueous ecosystems. Methods: Essential information on diatoms were reviewed and discussed towards impacts of diatoms on biosynthesis and bioremediation. Results: In this review, we present the recent progress in this century on the application of diatoms in waste degradation, synthesis of biomaterial, biomineraliza­tion, toxicity and toxic effects of mineral elements evaluations. Conclusion: Diatoms can be considered as metal toxicity bioindicators and they can be applied for biomineralization, synthesis of biomaterials, and degradation of wastes.

  13. An overview: biomolecules from microalgae for animal feed and aquaculture.

    Science.gov (United States)

    Yaakob, Zahira; Ali, Ehsan; Zainal, Afifi; Mohamad, Masita; Takriff, Mohd Sobri

    2014-12-01

    Despite being more popular for biofuel, microalgae have gained a lot of attention as a source of biomolecules and biomass for feed purposes. Algae farming can be established using land as well as sea and strategies can be designed in order to gain the products of specific interest in the optimal way. A general overview of the contributions of Algae to meet the requirements of nutrients in animal/aquaculture feed is presented in this study. In addition to its applications in animal/aquaculture feed, algae can produce a number of biomolecules including astaxanthin, lutein, beta-carotene, chlorophyll, phycobiliprotein, Polyunsaturated Fatty Acids (PUFAs), beta-1,3-glucan, and pharmaceutical and nutraceutical compounds which have been reviewed with respect to their commercial importance and current status. The review is further extended to highlight the adequate utilization of value added products in the feeds for livestock, poultry and aquaculture (with emphasis in shrimp farming).

  14. Treatment of fish processing wastewater with microalgae-containing microbiota.

    Science.gov (United States)

    Riaño, B; Molinuevo, B; García-González, M C

    2011-12-01

    Two photobioreactors inoculated with microalgae from a lagoon containing aerobically treated swine slurry and with sludge from a membrane submerged bioreactor treating winery wastewater were established to treat fish processing wastewater (FPW) at 23 and 31 °C, respectively. The hydraulic retention time (HRT) was decreased in the photobioreactors from 10 to 5 days. Ammonium was completely exhausted in both photobioreactors; however, volatilization was the main removal mechanism for the highest applied load whereas biomass assimilation was the main mechanism for the lowest applied load. Approximately 70% of TCOD (total chemical oxygen demand) and phosphate removal was achieved regardless of temperature. Biomass productivity was as much as 55% higher at 31 °C than at 23 °C. These results suggested that fish processing wastewater could be effectively treated using this technology. PMID:21983413

  15. Evaluation of hydrolysis-esterification biodiesel production from wet microalgae.

    Science.gov (United States)

    Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Li, Shuhong; Kitamura, Yutaka

    2016-08-01

    Wet microalgae hydrolysis-esterification route has the advantage to avoid the energy-intensive units (e.g. drying and lipid extraction) in the biodiesel production process. In this study, techno-economic evaluation of hydrolysis-esterification biodiesel production process was carried out and compared with conventional (usually including drying, lipid extraction, esterification and transesterification) biodiesel production process. Energy and material balance of the conventional and hydrolysis-esterification processes was evaluated by Aspen Plus. The simulation results indicated that drying (2.36MJ/L biodiesel) and triolein transesterification (1.89MJ/L biodiesel) are the dominant energy-intensive stages in the conventional route (5.42MJ/L biodiesel). By contrast, the total energy consumption of hydrolysis-esterification route can be reduced to 1.81MJ/L biodiesel, and approximately 3.61MJ can be saved to produce per liter biodiesel. PMID:27209457

  16. GROWING DOMINANT SPECIES OF MICROALGAE IN NORTH EASTERN BLACK SEA

    Directory of Open Access Journals (Sweden)

    Lifanchuk A. V.

    2013-11-01

    Full Text Available In this article we present data on the effect of addition of mineral nutrition elements in the structure of the phytoplankton community in the north-eastern part of the Black Sea in the different seasons. Experimental studies have shown that the increase in biomass of microalgae occurs at the simultaneous addition of nitrogen and phosphorus in the accumulative cultures. In the spring can get biomass Emiliania huxleyi, P.pseudodelicatissima, Chaetoceros curvisetus and Skeletonema costatum, in the summer – E. huxleyi, C. curvisetus, P.pseudodelicatissima, S.costatum, Thalassionema nitzschioides, Leptocylindrus danicus, Dactyliosolen fragilissimus, Proboscia alata, Pseudosolenia calcar-avis, in the autumn - C. curvisetus, S.costatum, Th. nitzschioides, L. danicus, D. fragilissimus

  17. Haloalkaline Bioconversions for Methane Production from Microalgae Grown on Sunlight.

    Science.gov (United States)

    Daelman, Matthijs R J; Sorokin, Dimitry; Kruse, Olaf; van Loosdrecht, Mark C M; Strous, Marc

    2016-06-01

    Microalgal biomass can be converted to biofuels to replace nonsustainable fossil fuels, but the widespread use of microalgal biofuels remains hampered by the high energetic and monetary costs related to carbon dioxide supply and downstream processing. Growing microalgae in mixed culture biofilms reduces energy demands for mixing, maintaining axenic conditions, and biomass concentration. Furthermore, maintaining a high pH improves carbon dioxide absorption rates and inorganic carbon solubility, thus overcoming the carbon limitation and increasing the volumetric productivity of the microalgal biomass. Digesting the microalgal biomass anaerobically at high pH results in biogas that is enriched in methane, while the dissolved carbon dioxide is recycled to the phototrophic reactor. All of the required haloalkaline conversions are known in nature. PMID:26968613

  18. Nutritional evaluation of microalgae oils rich in omega-3 long chain polyunsaturated fatty acids as an alternative for fish oil

    OpenAIRE

    Ryckebosch, Eline; Bruneel, Charlotte; Termote-Verhalle, Romina; Goiris, Koen; Muylaert, Koenraad; Foubert, Imogen

    2014-01-01

    The purpose of this work was to evaluate the nutritional value of the total lipid extract of different omega-3 long chain polyunsaturated fatty acids producing photoautotrophic microalgae in one study. It was shown that microalgae oils from Isochrysis, Nannochloropsis, Phaeodactylum, Pavlova and Thalassiosira contain sufficient omega-3 LC-PUFA to serve as an alternative for fish oil, which was used as the ‘golden standard’. In the microalgae oils an important part of the omega-3 long chain po...

  19. Enhanced lipid production of three microalgae Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp by manipulating of cultivation condition

    OpenAIRE

    Rukminasari, Nita

    2013-01-01

    Microalgae is one of potential source for biodiesel due to high efficiency of solar energy conversion to chemical energy. Several microalgae also have high lipid content per dry weight biomass. The aims of the present work to study the effects of temperature and nutrient depletion on the growth and lipid content of three selected microalgae (Dunaliella tertiolecta, Nannochloropsis sp and Scenedesmus sp) in view of their possible utilization as raw materials for biodiesel production. In ad...

  20. Biodiesel Fuel Production from Marine Microalgae Isochrysis galbana, Pavlova lutheri, Dunaliella salina and Measurement of its Viscosity and Density

    OpenAIRE

    T. Sujin Jeba Kumar; C.K. Balavigneswaran; K.P. Srinivasakumar

    2013-01-01

    Biodiesel is a fuel derives from transesterification of fats and oils. It is renewable and non-toxic ecofriendly fuel with less CO2 and NO2 emissions. Microalgae are known to contain more lipid content than macroalgae and most other oil crops. In this study, we extracted biodiesel from three microalgae Isochrysis galbana, Pavlova lutheri, Dunaliella salina and also measured the density and viscosity of biofuel obtained from these microalgae. Pavlova lutheri yielded more oil than the other two...

  1. Processing of Microalgae: Acoustic Cavitation and Hydrothermal Conversion

    Science.gov (United States)

    Greenly, Justin Michael

    The production of energy dense fuels from renewable algal biomass feedstocks -- if sustainably developed at a sufficiently large scale -- may reduce the consumption of petroleum from fossil fuels and provide many environmental benefits. Achieving economic feasibility has several technical engineering challenges that arise from dilute concentration of growing algae in aqueous media, small cell sizes, and durable cell walls. For microalgae to be a sustainable source of biofuels and co-products, efficient fractionation and conversion of the cellular contents is necessary. Research was carried out to address two processing options for efficient microalgae biofuel production: 1. Ultrasonic cavitation for cell disruption and 2. Hydrothermal conversion of a model algal triglyceride. 1. Ultrasonic cell disruption, which relies on cavitating bubbles in the suspension to produce damaging shock waves, was investigated experimentally over a range of concentrations and species types. A few seconds of high intensity sonication at fixed frequency yielded significant cell disruption, even for the more durable cells. At longer exposure times, effectiveness was seen to decline and was attributed, using acoustic measurements, to ultrasonic power attenuation in the ensuing cloud of cavitating bubbles. Processing at higher cell concentrations slowed cell disintegration marginally, but increased the effectiveness of dissipating ultrasonic energy. A theoretical study effectively predicted optimal conditions for a variety of parameters that were inaccessible in this experimental investigation. In that study, single bubble collapse was modeled to identify operating conditions that would increase cavitation, and thus cell disruption. Simulations were conducted by varying frequency and pressure amplitude of the ultrasound wave, and initial bubble size. The simulation results indicated that low frequency, high sound wave amplitudes, and small initial bubble size generate the highest shock

  2. Perfil de ácidos graxos de microalgas cultivadas com dióxido de carbono Fatty acids profile of microalgae cultived with carbon dioxide

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2008-08-01

    Full Text Available As microalgas são consideradas fontes potenciais de diversos compostos químicos. Os ácidos graxos obtidos da biomassa podem apresentar efeitos terapêuticos em humanos e podem ser usados para produção de biodiesel. Objetivou-se, neste trabalho verificar o conteúdo lipídico e o perfil dos ácidos graxos das microalgas Spirulina sp., Scenedesmus obliquus, Chlorella kessleri e Chlorella vulgaris cultivadas em diferentes concentrações de dióxido de carbono e bicarbonato de sódio. A microalga Chlorella kessleri cultivada com 12% de CO2 apresentou a maior concentração de lipídios na biomassa seca (9,7% p/p. A máxima concentração de ácidos graxos insaturados foi 72,0% (p/p para C. vulgaris cultivada com 12% de CO2. Para os ácidos graxos saturados o maior valor encontrado foi 81,6% (p/p, quando a microalga Spirulina sp. foi cultivada com 18% de CO2 e 16,8 g.L-1 de bicarbonato de sódio.Microalgae have a great potential as a source of several chemical compounds. The fatty acids have shown therapeutic effects and used to produce biodiesel. The aim of this work was to verify the lipid contents and the fatty acids profile of the microalga Spirulina sp., Scenedesmus obliquus, Chlorella kessleri and Chlorella vulgaris cultived in different carbon dioxide and sodium bicarbonate concentrations. The microalgae Chlorella kessleri cultived with 12% CO2 showed the highest lipid content in the dry biomass (9.7% p/p. The maximum unsaturated fatty acids concentration was 72.0% (p/p to C. vulgaris in the culture with 12% CO2. The highest saturated fatty acids value was 81.6% (p/p when microalga Spirulina sp. was cultived with 18% CO2 and 16.8 g.L-1 sodium bicarbonate.

  3. Evaluacion tecno-económica de la producción de biocombustibles a partir de microalgas = techno-economic assessment of biofuel production from microalgae

    OpenAIRE

    Jaramillo Obando, Juan Jacobo

    2011-01-01

    La finalidad de este trabajo de tesis fue estudiar la producción de biodiesel y bioetanol a partir de microalgas ricas en aceite y almidón a bajo costo. Todo esto respetando la tierra cultivable para alimentos, siendo amigable con el ambiente. A lo largo de esta propuesta se muestran técnicas de cultivo de biomasa de microalgas en sistemas abiertos y cerrados, métodos de recolección, extracción de metabolitos y dos caminos para la obtención de biocombustibles, al caso, etanol y biodiesel....

  4. Protein N-glycosylation in eukaryotic microalgae and its impact on the production of nuclear expressed biopharmaceuticals.

    Science.gov (United States)

    Mathieu-Rivet, Elodie; Kiefer-Meyer, Marie-Christine; Vanier, Gaëtan; Ovide, Clément; Burel, Carole; Lerouge, Patrice; Bardor, Muriel

    2014-01-01

    Microalgae are currently used for the production of food compounds. Recently, few microalgae species have been investigated as potential biofactories for the production of biopharmaceuticals. Indeed in this context, microalgae are cheap, classified as Generally Recognized As Safe (GRAS) organisms and can be grown easily. However, problems remain to be solved before any industrial production of microalgae-made biopharmaceuticals. Among them, post-translational modifications of the proteins need to be considered. Especially, N-glycosylation acquired by the secreted recombinant proteins is of major concern since most of the biopharmaceuticals are N-glycosylated and it is well recognized that glycosylation represent one of their critical quality attribute. Therefore, the evaluation of microalgae as alternative cell factory for biopharmaceutical productions thus requires to investigate their N-glycosylation capability in order to determine to what extend it differs from their human counterpart and to determine appropriate strategies for remodeling the microalgae glycosylation into human-compatible oligosaccharides. Here, we review the secreted recombinant proteins which have been successfully produced in microalgae. We also report on recent bioinformatics and biochemical data concerning the structure of glycans N-linked to proteins from various microalgae phyla and comment the consequences on the glycan engineering strategies that may be necessary to render those microalgae-made biopharmaceuticals compatible with human therapy.

  5. Mathematical modeling and experimental validation of Phaeodactylum tricornutum microalgae growth rate with glycerol addition

    Energy Technology Data Exchange (ETDEWEB)

    Morais, Keli Cristiane Correia; Ribeiro, Robert Luis Lara; Santos, Kassiana Ribeiro dos; Mariano, Andre Bellin [Mariano Center for Research and Development of Sustainable Energy (NPDEAS), Curitiba, PR (Brazil); Vargas, Jose Viriato Coelho [Departament of Mechanical Engineering, Federal University of Parana (UFPR) Curitiba, PR (Brazil)

    2010-07-01

    The Brazilian National Program for Bio fuel Production has been encouraging diversification of feedstock for biofuel production. One of the most promising alternatives is the use of microalgae biomass for biofuel production. The cultivation of microalgae is conducted in aquatic systems, therefore microalgae oil production does not compete with agricultural land. Microalgae have greater photosynthetic efficiency than higher plants and are efficient fixing CO{sub 2}. The challenge is to reduce production costs, which can be minimized by increasing productivity and oil biomass. Aiming to increase the production of microalgae biomass, mixotrophic cultivation, with the addition of glycerol has been shown to be very promising. During the production of biodiesel from microalgae there is availability of glycerol as a side product of the transesterification reaction, which could be used as organic carbon source for microalgae mixotrophic growth, resulting in increased biomass productivity. In this paper, to study the effect of glycerol in experimental conditions, the batch culture of the diatom Phaeodactylum tricornutum was performed in a 2-liter flask in a temperature and light intensity controlled room. During 16 days of cultivation, the number of cells per ml was counted periodically in a Neubauer chamber. The calculation of dry biomass in the control experiment (without glycerol) was performed every two days by vacuum filtration. In the dry biomass mixotrophic experiment with glycerol concentration of 1.5 M, the number of cells was assessed similarly in the 10{sup th} and 14{sup th} days of cultivation. Through a volume element methodology, a mathematical model was written to calculate the microalgae growth rate. It was used an equation that describes the influence of irradiation and concentration of nutrients in the growth of microalgae. A simulation time of 16 days was used in the computations, with initial concentration of 0.1 g l{sup -1}. In order to compare

  6. Informe APEI sobre movilidad

    OpenAIRE

    Arroyo Vázquez, Natalia

    2011-01-01

    Este informe incluye una amplia aproximación al concepto de movilidad, desde un punto de vista introductorio, que nunca antes en nuestro ámbito había abarcado todos los aspectos que tienen que ver con él, desde cuestiones técnicas como los dispositivos móviles, sistemas operativos y navegadores, conectividad y estándares —cuya intención es poder comprender todos aquellos aspectos relacionados con la movilidad y que tienen una incidencia directa sobre los contenidos— hasta otras más relacionad...

  7. Apuntes sobre liderazgo

    OpenAIRE

    Contreras, Manuel E.

    2010-01-01

    Este trabajo presenta una breve síntesis de las principales teorías de liderazgo y se centra sobre el enfoque de liderazgo adaptativo de Ronald Heifetz. El documento originalmente fue desarrollado para las sesiones de educación a distancia de INDES. Ha sido revisado para usar en otros ámbitos de capacitación y ha sido utilizado en sesiones presenciales llevadas a cabo por INDES, como por otras entidades en universidades y centros de capacitación de America Latina.

  8. Sobre el razonamiento judicial

    OpenAIRE

    Asís Roig, Rafael de

    1998-01-01

    El trabajo elabora modelos a través de los cuáles es posible reconstruir la argumentación judicial plasmada en las sentencias y, a la vez, hacer explícitas las reglas que sirven de justificación a sus decisiones, y el marco normativo utilizado como referencia. El estudio analiza tanto los pronunciamientos sobre hechos como los que se refieren a la calificación jurídica, en principio, desde una perspectiva descriptiva. Ahora bien, también se llevan a cabo reflexiones y propuestas que van más a...

  9. Puente sobre el Rin

    Directory of Open Access Journals (Sweden)

    Gortz, Wilhelm

    1961-12-01

    Full Text Available Del total de 35 proyectos presentados al concurso del puente para carretera sobre el Rin, entre Duisburg-Ruhrort y Homberg, sólo dos proposiciones de la Demag fueron consideradas: Una con tablero suspendido por vientos que parten de dos torres, y otra, con suspensión por cables flexibles que se apoyan en dos torres y anclaje en la misma estructura. Por razones netamente estéticas fue elegida la propuesta Demag de puente suspendido por cables, aunque la solución con vientos hubiera sido la más económica, teniendo en cuenta las condiciones existentes.

  10. Sobre la tragedia griega

    Directory of Open Access Journals (Sweden)

    Mauricio Vélez Upegui

    2015-01-01

    Full Text Available Luego de caracterizar la tragedia griega clásica como expresión de un arte ciudadano que participa por igual de un carácter festivo, cierto régimen discursivo y una clara inscripción físico-espacial, el texto se demora en considerar tres aspectos fundamentales de esta forma dramática inventada por los griegos, a saber: una exposición sobre las fuentes orales míticas de las que los autores echan mano para componer la historia de cada una de las piezas que son llevadas a escena al amparo de un espíritu agonal; una explicación del funcionamiento formal de la tragedia, basado en la alternancia de partes cantadas (coro y partes recitadas (héroe; y, finalmente, una acotación sobre el sentido –interno y externo– que la acción dramática posee, en tanto elemento articulador de la trama.

  11. Sobre historia mundial hoy

    Directory of Open Access Journals (Sweden)

    Vera Weiler

    2010-08-01

    Full Text Available Los procesos de globalización son una realidad; su enorme impacto sobre la vida humana los ha convertido en un tema recurrente sobre el que se escribe y se comenta a diario también en Colombia. Los libros que de ellos tratan, ante todo los que 10 hacen en tono crítico, baten records en la industria editorial en todo el mundo. Las expectativas que acerca del futuro abrigan cientos de millones de personas se relacionan con 10 que ellas esperan, para bien o para mal, de la globalización. Las posturas que los gobernantes ocupan al respecto en el mundo son, cuando menos de aceptación, generalmente de activa participación en pos de la globalización. Por un lado, crece la preocupación y se multiplican las protestas; por el otro, dominan los razonamientos de los especialistas en materia de maximización de los rendimientos de los capitales que presentan la globalización, al estilo que se viene imponiendo, como el camino ineludible del gobierno universal de la eficiencia. ¿Tienen que decir algo los historiadores frente a todo esto?.

  12. Enhanced productivity of a lutein-enriched novel acidophile microalga grown on urea.

    Science.gov (United States)

    Casal, Carlos; Cuaresma, Maria; Vega, Jose Maria; Vilchez, Carlos

    2011-01-01

    Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of β-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH cultivation from non-desired microorganism growth is one of the main advantages of acidophile microalgae production. Conversely, acidophile microalgae growth rates are usually very low compared to common microalgae growth rates. In this work, we show that mixotrophic cultivation on urea efficiently enhances growth and productivity of an acidophile microalga up to typical values for common microalgae, therefore approaching acidophile algal production towards suitable conditions for feasible outdoor production. Algal productivity and potential for carotenoid accumulation were analyzed as a function of the nitrogen source supplied. Several nitrogen conditions were assayed: nitrogen starvation, nitrate and/or nitrite, ammonia and urea. Among them, urea clearly led to the best cell growth (~4 × 10(8) cells/mL at the end of log phase). Ammonium led to the maximum chlorophyll and carotenoid content per volume unit (220 μg·mL(·1) and 35 μg·mL(·1), respectively). Interestingly, no significant differences in growth rates were found in cultures grown on urea as C and N source, with respect to those cultures grown on nitrate and CO(2) as nitrogen and carbon sources (control cultures). Lutein accumulated up to 3.55 mg·g(·1) in the mixotrophic cultures grown on urea. In addition, algal growth in a shaded culture revealed the first evidence for an active xanthophylls cycle operative in acidophile microalgae. PMID:21339944

  13. Marine microalgae used as food supplements and their implication in preventing cardiovascular diseases

    Directory of Open Access Journals (Sweden)

    Mimouni Virginie

    2015-07-01

    Full Text Available Marine microalgae are photosynthetic microorganisms producing numerous bioactive molecules of interest for health and disease care such as lipids rich in omega-3 fatty acids -as eicosapentaenoic acid (EPA, 20:5 n-3 and docosahexaenoic acid (DHA, 22:6 n-3- and carotenoids (e.g., β-carotene, fucoxanthin, astaxanthin. It has already been shown that these molecules, individually used, are benefic in the prevention of diseases such as those associated with the cardiovascular risks, but also in some carcinomas. When these molecules are combined, synergistic effects may be observed. Microalgae, as a dietary supplement, can be used to study these synergistic effects in animal models in which dyslipidemia can be induced by a nutrition treatment. Different marine microalgae of interest are studied in this context to determine their potential effect as an alternative source to marine omega-3 rich fish oils, actually widely used for human health. Actually, the pharmaceutical and nutrition industries are developing health research programs involving microalgae, trying to limit the dramatic reduction of fish stocks and the associated pollution in the marine environment. The aim of this review is threefold: (1 to present research on lipids, particularly long chain polyunsaturated fatty acids, as components of marine microalgae used as food supplements; (2 to present the health benefits of some microalgae or their extracts, in particular in the prevention of cardiovascular diseases and (3 to highlight the role of Odontella aurita, a marine microalga rich in EPA used as food supplement with the aim of preventing cardiovascular diseases.

  14. Enhanced Productivity of a Lutein-Enriched Novel Acidophile Microalga Grown on Urea

    Directory of Open Access Journals (Sweden)

    Carlos Vilchez

    2010-12-01

    Full Text Available Coccomyxa acidophila is an extremophile eukaryotic microalga isolated from the Tinto River mining area in Huelva, Spain. Coccomyxa acidophila accumulates relevant amounts of b-carotene and lutein, well-known carotenoids with many biotechnological applications, especially in food and health-related industries. The acidic culture medium (pH < 2.5 that prevents outdoor cultivation from non-desired microorganism growth is one of the main advantages of acidophile microalgae production. Conversely, acidophile microalgae growth rates are usually very low compared to common microalgae growth rates. In this work, we show that mixotrophic cultivation on urea efficiently enhances growth and productivity of an acidophile microalga up to typical values for common microalgae, therefore approaching acidophile algal production towards suitable conditions for feasible outdoor production. Algal productivity and potential for carotenoid accumulation were analyzed as a function of the nitrogen source supplied. Several nitrogen conditions were assayed: nitrogen starvation, nitrate and/or nitrite, ammonia and urea. Among them, urea clearly led to the best cell growth (~4 ´ 108 cells/mL at the end of log phase. Ammonium led to the maximum chlorophyll and carotenoid content per volume unit (220 mg·mL-1 and 35 mg·mL-1, respectively. Interestingly, no significant differences in growth rates were found in cultures grown on urea as C and N source, with respect to those cultures grown on nitrate and CO2 as nitrogen and carbon sources (control cultures. Lutein accumulated up to 3.55 mg·g-1 in the mixotrophic cultures grown on urea. In addition, algal growth in a shaded culture revealed the first evidence for an active xanthophylls cycle operative in acidophile microalgae.

  15. Cultivation factors and population size control the uptake of nitrogen by the microalgae Chlorella vulgaris when interacting with the microalgae growth-promoting bacterium Azospirillum brasilense.

    Science.gov (United States)

    de-Bashan, Luz E; Antoun, Hani; Bashan, Yoav

    2005-10-01

    Growth of and the capacity to take up nitrogen in the freshwater microalgae Chlorella vulgaris were studied while varying the concentrations of ammonium and nitrate, the pH and the source of carbon in a synthetic wastewater growth medium when co-immobilized in alginate beads with the microalgae growth-promoting bacterium Azospirillum brasilense. Analyses of 29 independent experiments showed that co-immobilization of the microalgae with A. brasilense could result in two independent phenomena directly affected by cultivation factors, such as nitrogen species, pH and presence of a carbon source. First, growth of the microalgal population increased without an increase in the capacity of the single cells to take up nitrogen, or second, the capacity of cells to take up nitrogen increased without an increase of the total microalgal population. These phenomena were dependent on the population density of the microalgae, which was in turn affected by cultivation factors. This supports the conclusion that the size of the microalgal population controls the uptake of nitrogen in C. vulgaris cells - the higher the population (regardless the experimental parameters), the less nitrogen each cell takes up.

  16. [Identification of Microalgae Species Using Visible/Near Infrared Transmission Spectroscopy].

    Science.gov (United States)

    Zhu, Hong-yan; Shao, Yong-ni; Jiang, Lu-lu; Guo, An-que; Pan, Jian; He, Yong

    2016-01-01

    At present, the identification and classification of the microalgae and its biochemical analysis have become one of the hot spots on marine biology research. Four microalgae species, including Chlorella vulgaris, Chlorella pyrenoidosa, Nannochloropsis oculata, Chlamydomonas reinhardtii, were chosen as the experimental materials. Using an established spectral acquisition system, which consists of a portable USB 4000 spectrometer having transmitting and receiving fiber bundles connected by a fiber optic probe, a halogen light source, and a computer, the Vis/NIR transmission spectral data of 120 different samples of the microalgae with different concentration gradients were collected, and the spectral curves of fourmicroalgae species were pre-processed by different pre-treatment methods (baseline filtering, convolution smoothing, etc. ). Based on the pre-treated effects, SPA was applied to select effective wavelengths (EWs), and the selected EWs were introduced as inputs to develop and compare PLS, Least Square Support Vector Machines (LS-SVM), Extreme Learning Machine (ELM)models, so as to explore the feasibility of using Vis/NIR transmission spectroscopy technology for the rapid identification of four microalgae species in situ. The results showed that: the effect of Savitzky-Golay smoothing was much better than the other pre-treatment methods. Six EWs selected in the spectraby SPA were possibly relevant to the content of carotenoids, chlorophyll in the microalgae. Moreover, the SPA-PLS model obtained better performance than the Full-Spectral-PLS model. The average prediction accuracy of three methods including SPA-LV-SVM, SPA-ELM, and SPA-PLS were 80%, 85% and 65%. The established method in this study may identify four microalgae species effectively, which provides a new way for the identification and classification of the microalgae species. The methodology using Vis/NIR spectroscopy with a portable optic probe would be applicable to a diverse range of microalgae

  17. Isolation and evaluation of oil-producing microalgae from subtropical coastal and brackish waters.

    Directory of Open Access Journals (Sweden)

    David K Y Lim

    Full Text Available Microalgae have been widely reported as a promising source of biofuels, mainly based on their high areal productivity of biomass and lipids as triacylglycerides and the possibility for cultivation on non-arable land. The isolation and selection of suitable strains that are robust and display high growth and lipid accumulation rates is an important prerequisite for their successful cultivation as a bioenergy source, a process that can be compared to the initial selection and domestication of agricultural crops. We developed standard protocols for the isolation and cultivation for a range of marine and brackish microalgae. By comparing growth rates and lipid productivity, we assessed the potential of subtropical coastal and brackish microalgae for the production of biodiesel and other oil-based bioproducts. This study identified Nannochloropsis sp., Dunaniella salina and new isolates of Chlorella sp. and Tetraselmis sp. as suitable candidates for a multiple-product algae crop. We conclude that subtropical coastal microalgae display a variety of fatty acid profiles that offer a wide scope for several oil-based bioproducts, including biodiesel and omega-3 fatty acids. A biorefinery approach for microalgae would make economical production more feasible but challenges remain for efficient harvesting and extraction processes for some species.

  18. Microalgae Harvest through Fungal Pelletization—Co-Culture of Chlorella vulgaris and Aspergillus niger

    Directory of Open Access Journals (Sweden)

    Sarman Oktovianus Gultom

    2014-07-01

    Full Text Available Microalgae harvesting is a labor- and energy-intensive process and new approaches to harvesting microalgae need to be developed in order to decrease the costs. In this study; co-cultivatation of filamentous fungus (Aspergillus niger and microalgae (Chlorella vulgaris to form cell pellets was evaluated under different conditions, including organic carbon source (glucose; glycerol; and sodium acetate concentration; initial concentration of fungal spores and microalgal cells and light. Results showed that 2 g/L of glucose with a 1:300 ratio of fungi to microalgae provided the best culturing conditions for the process to reach >90% of cell harvest efficiency. The results also showed that an organic carbon source was required to sustain the growth of fungi and form the cell pellets. The microalgae/fungi co-cultures at mixotrophic conditions obtained much higher total biomass than pure cultures of each individual strains; indicating the symbiotic relationship between two strains. This can benefit the microbial biofuel production in terms of cell harvest and biomass production.

  19. Combined Extraction Processes of Lipid from Chlorella vulgaris Microalgae: Microwave Prior to Supercritical Carbon Dioxide Extraction

    Directory of Open Access Journals (Sweden)

    Farid Chemat

    2011-12-01

    Full Text Available Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO2 extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO2. Work performed with pressure range of 20–28 Mpa and temperature interval of 40–70 °C, gave the highest extraction yield (w/w dry weight at 28 MPa/40 °C. MW-SCCO2 allowed to obtain the highest extraction yield (4.73% compared to SCCO2 extraction alone (1.81%. Qualitative and quantitative analyses of microalgae oil showed that palmitic, oleic, linoleic and α-linolenic acid were the most abundant identified fatty acids. Oils obtained by MW-SCCO2 extraction had the highest concentrations of fatty acids compared to SCCO2 extraction without pretreatment. Native form, and microwave pretreated and untreated microalgae were observed by scanning electronic microscopy (SEM. SEM micrographs of pretreated microalgae present tearing wall agglomerates. After SCCO2, microwave pretreated microalgae presented several micro cracks; while native form microalgae wall was slightly damaged.

  20. Paper-based device for separation and cultivation of single microalga.

    Science.gov (United States)

    Chen, Chih-Chung; Liu, Yi-Ju; Yao, Da-Jeng

    2015-12-01

    Single-cell separation is among the most useful techniques in biochemical research, diagnosis and various industrial applications. Microalgae species have great economic importance as industrial raw materials. Microalgae species collected from environment are typically a mixed and heterogeneous population of species that must be isolated and purified for examination and further application. Conventional methods, such as serial dilution and a streaking-plate method, are intensive of labor and inefficient. We developed a paper-based device for separation and cultivation of single microalga. The fabrication was simply conducted with a common laser printer and required only a few minutes without lithographic instruments and clean-room. The driving force of the paper device was simple capillarity without a complicated pump connection that is part of most devices for microfluidics. The open-structure design of the paper device makes it operable with a common laboratory micropipette for sample transfer and manipulation with a naked eye or adaptable to a robotic system with functionality of high-throughput retrieval and analysis. The efficiency of isolating a single cell from mixed microalgae species is seven times as great as with a conventional method involving serial dilution. The paper device can serve also as an incubator for microalgae growth on simply rinsing the paper with a growth medium. Many applications such as highly expressed cell selection and various single-cell analysis would be applicable. PMID:26459444

  1. The kinetics of Scenedesmus obliquus microalgae growth utilizing carbon dioxide gas from biogas

    International Nuclear Information System (INIS)

    Microalgae Scenedesmus obliquus was cultured in a laboratory photobioreactor to determine the efficacy of using biogas as a carbon source for the microalgae's growth. The biogas contained ∼60% CH4 and ∼40% CO2, and was derived from an anaerobic digester operating from animal wastes, and an anaerobic reactor utilizing high strength wastewater. The results showed that biogas is a viable carbon source for microalgae growth and that significant portions of the biogas' CO2 can be utilized for algae growth, resulting in a biogas having a high concentration of methane. This paper develops the kinetic expressions for the algae's growth by assuming an autocatalytic reaction between carbon substrate and microalgae. The maximum specific growth rate and biomass productivity of S. obliquus were 0.56 d−1 and 0.145 g L−1d−1 respectively. The biomass contained 51.8% carbon and higher heating value (HHV) was 22.9 MJ kg−1. - Highlights: • Biogas is a viable carbon source for microalgae growth. • Biomass production rate and characteristics were assessed. • Scenedesmus obliquus can adjust to grow with high concentration of CO2 in the carbon source

  2. A type 2 diacylglycerol acyltransferase accelerates the triacylglycerol biosynthesis in heterokont oleaginous microalga Nannochloropsis oceanica.

    Science.gov (United States)

    Li, Da-Wei; Cen, Shi-Ying; Liu, Yu-Hong; Balamurugan, Srinivasan; Zheng, Xin-Yan; Alimujiang, Adili; Yang, Wei-Dong; Liu, Jie-Sheng; Li, Hong-Ye

    2016-07-10

    Oleaginous microalgae have received a considerable attention as potential biofuel feedstock. However, lack of industry-suitable strain with lipid rich biomass limits its commercial applications. Targeted engineering of lipogenic pathways represents a promising strategy to enhance the efficacy of microalgal oil production. In this study, a type 2 diacylglycerol acyltransferase (DGAT), a rate-limiting enzyme in triacylglycerol (TAG) biosynthesis, was identified and overexpressed in heterokont oleaginous microalga Nannochloropsis oceanica for the first time. Overexpression of DGAT2 in Nannochloropsis increased the relative transcript abundance by 3.48-fold in engineered microalgae cells. TAG biosynthesis was subsequently accelerated by DGAT2 overexpression and neutral lipid content was significantly elevated by 69% in engineered microalgae. The fatty acid profile determined by GC-MS revealed that fatty acid composition was altered in engineered microalgae. Saturated fatty acids and polyunsaturated fatty acids were found to be increased whereas monounsaturated fatty acids content decreased. Furthermore, DGAT2 overexpression did not show negative impact on algal growth parameters. The present investigation showed that the identified DGAT2 would be a potential candidate for enhancing TAG biosynthesis and might facilitate the development of promising oleaginous strains with industrial potential. PMID:27164260

  3. In Metabolic Engineering of Eukaryotic Microalgae: Potential and Challenges Come with Great Diversity.

    Science.gov (United States)

    Gimpel, Javier A; Henríquez, Vitalia; Mayfield, Stephen P

    2015-01-01

    The great phylogenetic diversity of microalgae is corresponded by a wide arrange of interesting and useful metabolites. Nonetheless metabolic engineering in microalgae has been limited, since specific transformation tools must be developed for each species for either the nuclear or chloroplast genomes. Microalgae as production platforms for metabolites offer several advantages over plants and other microorganisms, like the ability of GMO containment and reduced costs in culture media, respectively. Currently, microalgae have proved particularly well suited for the commercial production of omega-3 fatty acids and carotenoids. Therefore most metabolic engineering strategies have been developed for these metabolites. Microalgal biofuels have also drawn great attention recently, resulting in efforts for improving the production of hydrogen and photosynthates, particularly triacylglycerides. Metabolic pathways of microalgae have also been manipulated in order to improve photosynthetic growth under specific conditions and for achieving trophic conversion. Although these pathways are not strictly related to secondary metabolites, the synthetic biology approaches could potentially be translated to this field and will also be discussed. PMID:26696985

  4. Current status and outlook in the application of microalgae in biodiesel production and environmental protection

    Directory of Open Access Journals (Sweden)

    Xin eZhang

    2014-08-01

    Full Text Available Microalgae have been currently recognized as one group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO2 fixation, NOX and wastewater treatment and biorefinery have been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy balance. This review gives an overview of the current status of the application of microalgae in biodiesel production and environmental protection. The practical problems not only facing the microalgae biodiesel production but also associated with microalgae application for environmental pollution control, in particular biological fixation of greenhouse gas (CO2 and NOX and wastewater treatment are described in detail. Notably, the synergistic combination of various applications (e.g. food, medicine, wastewater treatment and flue gas treatment with biodiesel production could enhance the sustainability and economics of the algal biodiesel production system.

  5. Chlorella protothecoides Microalgae as an Alternative Fuel for Tractor Diesel Engines

    Directory of Open Access Journals (Sweden)

    Saddam H. Al-lwayzy

    2013-02-01

    Full Text Available Biodiesel has attracted a great deal attention recently as an alternative fuel due to increasing fuel prices and the imperative to reduce emissions. Among a wide range of biodiesel resources, microalgae are a promising alternative fuel source because of the high biomass, lipid productivity and environmentally friendliness. Microalgae is also a non-edible food, therefore, there will be no impact on the human food supply chain. In this work, petroleum diesel (PD and biodiesel from the microalgae Chlorella protothecoides (MCP-B20 blend have been used to examine the performance and the emission of a 25.8 kW agriculture tractor engine. Two engine speeds at maximum power take off (PTO power and torque have been selected for analysis using analysis of variance (ANOVA. The results showed that there is no significant difference between the engine performance when microalgae biodiesel blend (MCP-B20 and PD were used. However, a significant reduction in CO, CO2 and NO emissions was found when MCP-B20 was used. These outcomes give strong indication that microalgae can be successfully used in tractors as alternative fuel.

  6. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura

    2003-05-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 January to 31 March 2003 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work during the previous reporting period, PSI conducted preparation work on direct feeding of coal combustion gas to microalgae and developed a design concept for photobioreactors for biofixation of CO{sub 2} and photovoltaic power generation. Aquasearch continued their effort on characterization of microalgae suitable for CO{sub 2} sequestration and preparation for pilot scale demonstration. University of Hawaii continued effort on system optimization of the CO{sub 2} sequestration system.

  7. Microalgae Recovery from Water for Biofuel Production Using CO2-Switchable Crystalline Nanocellulose.

    Science.gov (United States)

    Ge, Shijian; Champagne, Pascale; Wang, Haidong; Jessop, Philip G; Cunningham, Michael F

    2016-07-19

    There is a pressing need to develop efficient and sustainable approaches to harvesting microalgae for biofuel production and water treatment. CO2-switchable crystalline nanocellulose (CNC) modified with 1-(3-aminopropyl)imidazole (APIm) is proposed as a reversible coagulant for harvesting microalgae. Compared to native CNC, the positively charged APIm-modified CNC, which dispersed well in carbonated water, showed appreciable electrostatic interaction with negatively charged Chlorella vulgaris upon CO2-treatment. The gelation between the modified CNC, triggered by subsequent air sparging, can also enmesh adjacent microalgae and/or microalgae-modified CNC aggregates, thereby further enhancing harvesting efficiencies. Moreover, the surface charges and dispersion/gelation of APIm-modified CNC could be reversibly adjusted by alternatively sparging CO2/air. This CO2-switchability would make the reusability of redispersed CNC for further harvesting possible. After harvesting, the supernatant following sedimentation can be reused for microalgal cultivation without detrimental effects on cell growth. The use of this approach for harvesting microalgae presents an advantage to other current methods available because all materials involved, including the cellulose, CO2, and air, are natural and biocompatible without adverse effects on the downstream processing for biofuel production. PMID:27314988

  8. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Takashi Nakamura

    2003-04-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 October to 31 December 2002 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on feasibility demonstration of direct feeding of coal combustion gas to microalgae. Aquasearch continued their effort on selection and characterization of microalgae suitable for CO{sub 2} sequestration. University of Hawaii continued effort on system optimization of the CO{sub 2} sequestration system.

  9. Identification of Microalgae by Laser Desorption/Ionization Mass Spectrometry Coupled with Multiple Nanomatrices.

    Science.gov (United States)

    Peng, Lung-Hsiang; Unnikrishnan, Binesh; Shih, Chi-Yu; Hsiung, Tung-Ming; Chang, Jeng; Hsu, Pang-Hung; Chiu, Tai-Chia; Huang, Chih-Ching

    2016-04-01

    In this study, we demonstrate a simple method to identify microalgae by surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) using three different substrates: HgSe, HgTe, and HgTeSe nanostructures. The fragmentation/ionization processes of complex molecules in algae varied according to the heat absorption and transfer efficiency of the nanostructured matrices (NMs). Therefore, the mass spectra obtained for microalgae showed different patterns of m/z values for different NMs. The spectra contained both significant and nonsignificant peaks. Constructing a Venn diagram with the significant peaks obtained for algae when using HgSe, HgTe, and HgTeSe NMs in m/z ratio range 100-1000, a unique relationship among the three sets of values was obtained. This unique relationship of sets is different for each species of microalgae. Therefore, by observing the particular relationship of sets, we successfully identified different algae such as Isochrysis galbana, Emiliania huxleyi, Thalassiosira weissflogii, Nannochloris sp., Skeletonema cf. costatum, and Tetraselmis chui. This simple and cost-effective SALDI-MS analysis method coupled with multi-nanomaterials as substrates may be extended to identify other microalgae and microorganisms in real samples. Graphical Abstract Identification of microalgae by surface-assisted laser desorption/ionization mass spectrometry coupled with three different mercury-based nanosubstrates. PMID:26842733

  10. Metabolic Engineering of Eukaryotic Microalgae: Potential and Challenges come with great diversity

    Directory of Open Access Journals (Sweden)

    Javier A Gimpel

    2015-12-01

    Full Text Available The great phylogenetic diversity of microalgae is corresponded by a wide arrange of interesting and useful metabolites. Nonetheless metabolic engineering in microalgae has been limited, since specific transformation tools must be developed for each species for either the nuclear or chloroplast genomes. Microalgae as production platforms for metabolites offer several advantages over plants and other microorganisms, like the ability of GMO containment and reduced costs in culture media, respectively. Currently, microalgae have proved particularly well suited for the commercial production of omega-3 fatty acids and carotenoids. Therefore most metabolic engineering strategies have been developed for these metabolites. Microalgal biofuels have also drawn great attention recently, resulting in efforts for improving the production of hydrogen and photosynthates, particularly triacylglycerides. Metabolic pathways of microalgae have also been manipulated in order to improve photosynthetic growth under specific conditions and for achieving trophic conversion. Although these pathways are not strictly related to secondary metabolites, the synthetic biology approaches could potentially be translated to this field and will also be discussed.

  11. Paper-based device for separation and cultivation of single microalga.

    Science.gov (United States)

    Chen, Chih-Chung; Liu, Yi-Ju; Yao, Da-Jeng

    2015-12-01

    Single-cell separation is among the most useful techniques in biochemical research, diagnosis and various industrial applications. Microalgae species have great economic importance as industrial raw materials. Microalgae species collected from environment are typically a mixed and heterogeneous population of species that must be isolated and purified for examination and further application. Conventional methods, such as serial dilution and a streaking-plate method, are intensive of labor and inefficient. We developed a paper-based device for separation and cultivation of single microalga. The fabrication was simply conducted with a common laser printer and required only a few minutes without lithographic instruments and clean-room. The driving force of the paper device was simple capillarity without a complicated pump connection that is part of most devices for microfluidics. The open-structure design of the paper device makes it operable with a common laboratory micropipette for sample transfer and manipulation with a naked eye or adaptable to a robotic system with functionality of high-throughput retrieval and analysis. The efficiency of isolating a single cell from mixed microalgae species is seven times as great as with a conventional method involving serial dilution. The paper device can serve also as an incubator for microalgae growth on simply rinsing the paper with a growth medium. Many applications such as highly expressed cell selection and various single-cell analysis would be applicable.

  12. An annular photobioreactor with ion-exchange-membrane for non-touch microalgae cultivation with wastewater.

    Science.gov (United States)

    Chang, Hai-Xing; Fu, Qian; Huang, Yun; Xia, Ao; Liao, Qiang; Zhu, Xun; Zheng, Ya-Ping; Sun, Chi-He

    2016-11-01

    To eliminate the negative impacts of pollutants in wastewater (such as suspended solids, excess N, P, heavy metals) on microalgae growth, an annular ion-exchange-membrane photobioreactor (IEM-PBR) was proposed in this study. The IEM-PBR could avoid direct mixing of algae cells with wastewater by separating them into two chambers. In the IEM-PBR, the nutrients (mainly N and P) in wastewater continuously permeated into microalgae cultures through the ion-exchange-membrane for microalgae growth, while the pollutants hardly permeated into microalgae cultures. Three types of representative wastewater were investigated to evaluate the performance of the IEM-PBR. When cultivated with wastewater containing excess nutrients, high turbidity and excess heavy metals, microalgae biomass concentrations were significantly improved from 2.34, 2.15 and 0gL(-1) in the traditional PBR to 4.24, 3.13 and 2.04gL(-1) in the IEM-PBR. Correspondingly, the removal efficiencies of N and P in wastewater were also greatly improved by using the IEM-PBR. PMID:27544917

  13. In Metabolic Engineering of Eukaryotic Microalgae: Potential and Challenges Come with Great Diversity

    Science.gov (United States)

    Gimpel, Javier A.; Henríquez, Vitalia; Mayfield, Stephen P.

    2015-01-01

    The great phylogenetic diversity of microalgae is corresponded by a wide arrange of interesting and useful metabolites. Nonetheless metabolic engineering in microalgae has been limited, since specific transformation tools must be developed for each species for either the nuclear or chloroplast genomes. Microalgae as production platforms for metabolites offer several advantages over plants and other microorganisms, like the ability of GMO containment and reduced costs in culture media, respectively. Currently, microalgae have proved particularly well suited for the commercial production of omega-3 fatty acids and carotenoids. Therefore most metabolic engineering strategies have been developed for these metabolites. Microalgal biofuels have also drawn great attention recently, resulting in efforts for improving the production of hydrogen and photosynthates, particularly triacylglycerides. Metabolic pathways of microalgae have also been manipulated in order to improve photosynthetic growth under specific conditions and for achieving trophic conversion. Although these pathways are not strictly related to secondary metabolites, the synthetic biology approaches could potentially be translated to this field and will also be discussed. PMID:26696985

  14. Direct biodiesel production from wet microalgae biomass of Chlorella pyrenoidosa through in situ transesterification.

    Science.gov (United States)

    Cao, Hechun; Zhang, Zhiling; Wu, Xuwen; Miao, Xiaoling

    2013-01-01

    A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90°C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% as water content increased from 0% to 90%. Higher temperature could compensate the negative effect. When temperature reached 150°C, there was no negative effect, and biodiesel yield was over 100%. Based on the above research, wet microalgae biomass was directly applied to biodiesel production, and the optimal conditions were investigated. Under the optimal conditions of 100 mg dry weight equivalent wet microalgae biomass, 4 mL methanol, 8 mL n-hexane, 0.5 M H2SO4, 120°C, and 180 min reaction time, the biodiesel yield reached as high as 92.5% and the FAME content was 93.2%. The results suggested that biodiesel could be effectively produced directly from wet microalgae biomass and this effort may offer the benefits of energy requirements for biodiesel production.

  15. Direct Biodiesel Production from Wet Microalgae Biomass of Chlorella pyrenoidosa through In Situ Transesterification

    Directory of Open Access Journals (Sweden)

    Hechun Cao

    2013-01-01

    Full Text Available A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90°C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% as water content increased from 0% to 90%. Higher temperature could compensate the negative effect. When temperature reached 150°C, there was no negative effect, and biodiesel yield was over 100%. Based on the above research, wet microalgae biomass was directly applied to biodiesel production, and the optimal conditions were investigated. Under the optimal conditions of 100 mg dry weight equivalent wet microalgae biomass, 4 mL methanol, 8 mL n-hexane, 0.5 M H2SO4, 120°C, and 180 min reaction time, the biodiesel yield reached as high as 92.5% and the FAME content was 93.2%. The results suggested that biodiesel could be effectively produced directly from wet microalgae biomass and this effort may offer the benefits of energy requirements for biodiesel production.

  16. Voz sobre frame relay

    OpenAIRE

    D´Elia, Gabriel Anibal

    2000-01-01

    Esta tesis trata el tema de VOFR, desde la digitalización de la voz hasta su transmisión a través de dicha red, así también como la comparación con otros medios de transporte como VOIP. Dada las características del protocolo frame relay y su disponibilidad se eligió como el medio más apropiado para la transmisión de voz y datos en forma integrada sobre una misma red. El trabajo comienza con una breve explicación de la voz, su digitalización y forma actual de transmisión a través de una red di...

  17. Excertos sobre o sedentarismo

    Directory of Open Access Journals (Sweden)

    Alexandre Palma

    2014-09-01

    Full Text Available O sedentarismo tem sido tratado como algo perfeitamente determinável, objetivo e, portanto, que pode ser apreendido. Por outro lado, o conceito de sedentarismo ainda permanece questionável e, por conseguinte, os instrumentos mostram-se inconsistentes. Neste sentido, o objetivo do presente estudo foi mostrar que diferentes discursos de verdade vêm concorrendo por esse conceito, o que nos motiva a pensar qual é a verdade ou, até mesmo, se há alguma verdade sobre ele. Após apresentarmos diferentes possibilidades de compreender o sedentarismo, através do uso de aforismos, entendemos que postular um discurso como verdade talvez apenas signifique que as pessoas nele creem e que há uma vontade de verdade como uma vontade voltada para o poder.

  18. Enhanced attached growth of microalgae Scenedesmus. LX1 through ambient bacterial pre-coating of cotton fiber carriers.

    Science.gov (United States)

    Zhuang, Lin-Lan; Azimi, Yaldah; Yu, Dawei; Wang, Wen-Long; Wu, Yin-Hu; Dao, Guo-Hua; Hu, Hong-Ying

    2016-10-01

    The role of bacteria/extracellular polymeric substances (EPS) coated carriers on attached microalgae growth in suspended-solid phase photobioreactor (sspBR) was assessed in this study. The results showed that pre-coating cotton with ambient bacteria and their EPS improved the attached microalgal growth by as much as 230% in terms of attached microalgae density. Additionally, the single cell dry weight, chemical composition and oxygen evolving activity of attached microalgae were significantly affected by the presence of bacteria/EPS coating on the cotton carriers. The protein content of microalgae cells cultivated in the ssPBRs with carriers coated by bacteria and sterilized bacteria were on average 26% and 15% more than uncoated carriers, respectively. Through absorbing and immobilizing nutrients from the bulk medium, the bacteria/EPS coating provided the attached microalgae with nitrogen/phosphorus for protein synthesis, especially during the late stages of batch cultivation. PMID:27416514

  19. Modeling of the Kinetics of Supercritical Fluid Extraction of Lipids from Microalgae with Emphasis on Extract Desorption

    Directory of Open Access Journals (Sweden)

    Helena Sovová

    2016-05-01

    Full Text Available Microalgae contain valuable biologically active lipophilic substances such as omega-3 fatty acids and carotenoids. In contrast to the recovery of vegetable oils from seeds, where the extraction with supercritical CO2 is used as a mild and selective method, economically viable application of this method on similarly soluble oils from microalgae requires, in most cases, much higher pressure. This paper presents and verifies hypothesis that this difference is caused by high adsorption capacity of microalgae. Under the pressures usually applied in supercritical fluid extraction from plants, microalgae bind a large fraction of the extracted oil, while under extremely high CO2 pressures their adsorption capacity diminishes and the extraction rate depends on oil solubility in supercritical CO2. A mathematical model for the extraction from microalgae was derived and applied to literature data on the extraction kinetics in order to determine model parameters.

  20. Research Progress on Cultivation Methods of Microalgae%微藻培养方法研究进展

    Institute of Scientific and Technical Information of China (English)

    尚常花; 朱顺妮; 王忠铭; 袁振宏; 谢君

    2016-01-01

    微藻是一种有前景的生物柴油原料。微藻培养是微藻生物柴油生产过程的重要环节。本文就微藻培养方法的研究进展进行了阐述。对自养、异养及兼养三种培养方法进行了比较,并对微藻培养提出了建议。%Microalgae is a promising feedstock for biodiesel production. Cultivation of microalgae is a key step in the process of producing biodiesel using microalgae as raw material. Research progress on cultivation methods of microalgae is discussed. Phototrophic cultivation, heterotrophic cultivation and mixotrophic cultivation are compared. Suggestions about cultivation of microalgae are proposed in this article.

  1. Toxicity and Accumulation of Selenite in Four Microalgae

    Institute of Scientific and Technical Information of China (English)

    王大志; 程兆第; 李少菁; 高亚辉

    2003-01-01

    The toxicity and bioaccumlation of selenite in four microalgae, Spirulina platensis,Dunaliella salina, Dunaliella bardawill and Phaeodactylum tricornutum cultured in the presence of selenite were investigated. Lower concentrations of selenite were generally nontoxic and frequently stimulated algal growth, while higher concentrations of selenite inhibited algal growth. Selenite was more toxic to D. salina and D. bardawill than to S. platensis and P. tricornutum. All algae cultured in selenite were able to incorporate Se to different degrees, which depended on algal species. The distributions of selenite among intracellular macromolecular compounds were different among algal species: most of the selenite was associated with proteins in S. platensis, D. salina and D. bardawill, while most of the selenite was associated with lipids in P. tricornutum, which reflected the physiological differences among the algae. These observations suggest that algae are able to accumulate selenite and bind it with intracellular macromolecular compounds when exposed to high concentration of selenite. This may represent a form of storage or detoxification of selenite by the algae.

  2. Microalgae respond differently to nitrogen availability during culturing

    Indian Academy of Sciences (India)

    Liliana G Gigova; Natalia J Ivanova

    2015-06-01

    Variations in the exogenous nitrogen level are known to significantly affect the physiological status and metabolism of microalgae. However, responses of red, green and yellow-green algae to nitrogen (N) availability have not been compared yet. Porphyridium cruentum, Scenedesmus incrassatulus and Trachydiscus minutus were cultured in the absence of N in the medium and subsequent resupply of N to the starved cells. Culture growth and in-gel changes in isoenzyme pattern and activity of glutamate synthase, glutamate dehydrogenase, malate dehydrogenase, aspartate aminotransferase, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase were studied. The results demonstrated that the algae responded to the fully N-depleted and N-replete culture conditions by species-specific metabolic enzyme changes, suggesting differential regulation of both enzyme activity and cellular metabolism. Substantial differences in the activities of the antioxidant enzymes between N-depleted and N-replete cells of each species as well as between the species were also found. In the present work, besides the more general responses, such as adjustment of growth and pigmentation, we report on the involvement of specific metabolic and antioxidant enzymes and their isoforms in the mechanisms operating during N starvation and recovery in P. cruentum, T. minutus and S. incrassatulus.

  3. Potential of microalgae and cyanobacteria in bioremediation of distillery wastewaters

    Directory of Open Access Journals (Sweden)

    Isis Amores-Sanchez

    2015-01-01

    Full Text Available Los efluentes de destilerías, también llamados vinazas, son unos de los residuales más agresivos para el medio ambiente. Muchos estudios han focalizado los biotratamientos al uso de hongos y bacterias, pero la descontaminación eficiente de dicho efluente es todavía un problema sin resolver. En los últimos tiempos microalgas y cianobacterias han surgido como una alternativa muy promisoria a la destoxificación. Estos microorganismo ofrecen una serie de ventajas como son: la degradación de gran cantidad de contaminantes, síntesis de metabolitos con alto valor agregado, utilización de una fuente de energía abundante y barata (Luz solar, utilización de su biomasa para la producción de una gran variedad de compuestos con aplicaciones en la industria química y farmaceútica entre otras. En esta revisión abordamos el potencial de estos microorganismos para tratar sustancias contaminantes estructuralmente relacionadas con las vinazas, su capacidad para metabolizar compuestos fenolicos como lignina y taninos así como la degradación de las melanoidinas, compuesto recalcitrante presente en las vinazas y responsable de su color oscuro.

  4. Phototrophic pigment production with microalgae: biological constraints and opportunities.

    Science.gov (United States)

    Mulders, Kim J M; Lamers, Packo P; Martens, Dirk E; Wijffels, René H

    2014-04-01

    There is increasing interest in naturally produced colorants, and microalgae represent a bio-technologically interesting source due to their wide range of colored pigments, including chlorophylls (green), carotenoids (red, orange and yellow), and phycobiliproteins (red and blue). However, the concentration of these pigments, under optimal growth conditions, is often too low to make microalgal-based pigment production economically feasible. In some Chlorophyta (green algae), specific process conditions such as oversaturating light intensities or a high salt concentration induce the overproduction of secondary carotenoids (β-carotene in Dunaliella salina (Dunal) Teodoresco and astaxanthin in Haematococcus pluvialis (Flotow)). Overproduction of all other pigments (including lutein, fucoxanthin, and phycocyanin) requires modification in gene expression or enzyme activity, most likely combined with the creation of storage space outside of the photosystems. The success of such modification strategies depends on an adequate understanding of the metabolic pathways and the functional roles of all the pigments involved. In this review, the distribution of commercially interesting pigments across the most common microalgal groups, the roles of these pigments in vivo and their biosynthesis routes are reviewed, and constraints and opportunities for overproduction of both primary and secondary pigments are presented.

  5. Assessment of photosynthesis regulation in mixotrophically cultured microalga Chlorella sorokiniana

    Energy Technology Data Exchange (ETDEWEB)

    Li, Tingting; Kirchhoff, Helmut; Gargouri, Mahmoud; Feng, Jie; Cousins, Asaph B.; Pienkos, Philip T.; Gang, David R.; Chen, Shulin

    2016-11-01

    Mixotrophic growth of microalgae offers great potential as an efficient strategy for biofuel production. In this study, photosynthetic regulation of mixotrophically cultured Chlorella sorokiniana cells was systematically evaluated. Mixotrophic cells in the exponential growth phase showed the highest photosynthetic activity, where maximum photosynthetic O2 evolution was approximately 3- and 4-fold higher than cells in the same phase grown photoautotrophically in 1% CO2 (in air) and air, respectively. Additionally, characteristic chlorophyll fluorescence parameters demonstrated that no limitation in electron transport downstream of PSII was detected in mixotrophic cells. Up-regulation of photosynthetic activity was associated with high total ribulose-1, 5-bisphosphate carboxylase/oxygenase (Rubisco) carboxylase activity and expression level of phosphoribulokinase (PRK). After 3 days, photosynthetic O2 evolution of mixotrophic cells that went to the stationary phase, was strongly reduced, with reduced photochemical efficiency and reorganization of the PSII complex. Simultaneously, enzymatic activity for Rubisco carboxylase and mRNA levels of Rubisco and PRK diminished. Importantly, there was almost no non-photochemical quenching for mixotrophic cells, whether grown in log or stationary phase. A decline in the quantum efficiency of PSII and an oxidized plastoquinone pool (PQ pool) was observed under N-depleted conditions during mixotrophic growth. These results demonstrate that photosynthesis is regulated differently in mixotrophically cultured C. sorokiniana cells than in cells grown under photoautotrophic conditions, with a particularly strong impact by nitrogen levels in the cells.

  6. Delayed luminescence of microalgae as an indicator of metal toxicity

    International Nuclear Information System (INIS)

    The delayed luminescence (DL) (i.e. the photo-induced photon emission long after the illumination is switched off) of unicellular green algae samples has been measured when different concentrations of heavy metals are added to the standard culture medium, with the aim of assessing the DL as a promising approach for assaying the toxicity of contaminants such as metals. In particular, samples of freshwater green micro-algae Selenastrum capricornutum have been used. Concentrations of cadmium, chromium, lead and copper, ranging from 10-5 to 10-2 M, have been tested. The analysis of the decay trends, in the time interval from tens of microseconds to seconds, of the DL spectral components demonstrates that the DL parameters are sensitive to the presence of such pollutants. More precisely, the performed analysis allowed us to determine phenomenological relationships between the DL parameters and the metal concentration that could be used in view of the possibility of realizing a biosensor for water pollution detection. Attempts to distinguish between different contaminants are also described. Results of this preliminary study show that the DL measure based technique is suitable as a general bioassay of metal contamination and it could also be used to test the efficiency in bioavailability studies

  7. Quantitative assessment of microalgae biomass and lipid stability post cultivation

    Directory of Open Access Journals (Sweden)

    Katerine eNapan

    2015-04-01

    Full Text Available Processing of microalgal biomass to biofuels and other products requires the removal of the culture from a well-controlled growth system to a containment or preprocessing step at non-ideal growth conditions, such as darkness, minimal gas exchange, and fluctuating temperatures. The conditions and the length of time between harvest and processing will impact microalgal metabolism resulting in biomass and lipid degradation. This study experimentally investigates the impact of time and temperature on Nannochloropsis salina harvested from outdoor plate photobioreactors. The impact of three temperatures, 4°, 40° or 70°C, on biomass and lipid content (as fatty acid methyl esters of the harvested microalgae was evaluated over a 156 hour time period. Results show that for N. salina, time and temperature are key factors that negatively impact biomass and lipid yields. The temperature of 70°C resulted in the highest degradation with the overall biofuel potential reduced by 30% over 156 hours. Short time periods, 24 hours, and low temperatures are shown to have little effect on the harvested biomass.

  8. Design of a Novel Photobioreactor for Culture of Microalgae

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents the design of a novel photobioreactor for cultivation of microalgae. The body of the reactor with volume of about 40 L is parallelipipedic and divided in five compartments that can be put in series. The optical guides, plunged perpendicularly into the compartments, are upright Plexiglas plates on which side faces there are defined grooves that are able to diffuse light laterally and ensure an even distribution of light in the medium. External airlifts through the side columns are used for mixing of culture medium. The external light source is a SON-T lamp mounted inside a projector that provides a conical light dispersion, it is interchangeable and may take different positions. The design offers the photobioreactor characteristics including mainly interchangeable light source, homogenous distribution of light, perfect mixing of suspension of algae, high ratio of illuminating surface to volume of reactor, compactness and absence of contamination. Schemes, view of the photobioractor and data of continuous culture for Spirulina maxima are presented.

  9. Bioactive Compounds Isolated from Microalgae in Chronic Inflammation and Cancer

    Directory of Open Access Journals (Sweden)

    Elena Talero

    2015-09-01

    Full Text Available The risk of onset of cancer is influenced by poorly controlled chronic inflammatory processes. Inflammatory diseases related to cancer development include inflammatory bowel disease, which can lead to colon cancer, or actinic keratosis, associated with chronic exposure to ultraviolet light, which can progress to squamous cell carcinoma. Chronic inflammatory states expose these patients to a number of signals with tumorigenic effects, including nuclear factor kappa B (NF-κB and mitogen-activated protein kinases (MAPK activation, pro-inflammatory cytokines and prostaglandins release and ROS production. In addition, the participation of inflammasomes, autophagy and sirtuins has been demonstrated in pathological processes such as inflammation and cancer. Chemoprevention consists in the use of drugs, vitamins, or nutritional supplements to reduce the risk of developing or having a recurrence of cancer. Numerous in vitro and animal studies have established the potential colon and skin cancer chemopreventive properties of substances from marine environment, including microalgae species and their products (carotenoids, fatty acids, glycolipids, polysaccharides and proteins. This review summarizes the main mechanisms of actions of these compounds in the chemoprevention of these cancers. These actions include suppression of cell proliferation, induction of apoptosis, stimulation of antimetastatic and antiangiogenic responses and increased antioxidant and anti-inflammatory activity.

  10. Fuel Property of Biodiesel Made from Microalgae (Chlorella Sp.

    Directory of Open Access Journals (Sweden)

    S. V. Kelaiya,

    2015-12-01

    Full Text Available Microalgae chlorella is an organism capable of photosynthesis that is less than 2mm in diameter. The biodiesel extracted from algae using chloroform/methanol extraction solvent system then undergone three different transesterification processes based on three different catalysts viz. Alkali catalyst, Acid catalyst and Enzymatic catalyst with two temperature (50°C and 60 °C and with 1:5 methanol to bio-oil ratio. After transesterification using different catalysts, the fuel properties were measured. All the properties were compared with standard value of ASTM D 6751 standards. Alkali catalyst yield highest biodiesel (92 % at 60 °C temperature. Also, the closest value of different fuel properties found at par with standard value of ASTM D 6751 standards viz. moisture content, carbon residue, calorific value, specific gravity, acid value, flash point, viscosity, density, viscosity were found to be 0.01%, 0.04%, 40.41 MJ/kg, 0.83, 0.23 mg KOH/g, 143.67 °C, 5.16 mm2/s, 0.83 g/cm3 respectively in the biodiesel which was yield by transesterification done using Alkali catalyst (0.56 % NaOH at 60 °C temperature.

  11. Phosphorus from wastewater to crops: An alternative path involving microalgae.

    Science.gov (United States)

    Solovchenko, Alexei; Verschoor, Antonie M; Jablonowski, Nicolai D; Nedbal, Ladislav

    2016-01-01

    Phosphorus (P) is a non-renewable resource, a major plant nutrient that is essential for modern agriculture. Currently, global food and feed production depends on P extracted from finite phosphate rock reserves mainly confined to a small number of countries. P limitation and its potential socio-economic impact may well exceed the potential effects of fossil fuel scarcity. The efficiency of P usage today barely reaches 20%, with the remaining 80% ending up in wastewater or in surface waters as runoff from fields. When recovered from wastewater, either chemically or biologically, P is often present in a form that does not meet specifications for agricultural use. As an alternative, the potential of microalgae to accumulate large quantities of P can be a way to direct this resource back to crop plants. Algae can acquire and store P through luxury uptake, and the P enriched algal biomass can be used as bio-fertilizer. Technology of large-scale algae cultivation has made tremendous progress in the last decades, stimulated by perspectives of obtaining third generation biofuels without requiring arable land or fresh water. These new cultivation technologies can be used for solar-driven recycling of P and other nutrients from wastewater into algae-based bio-fertilizers. In this paper, we review the specifics of P uptake from nutrient-rich waste streams, paying special attention to luxury uptake by microalgal cells and the potential application of P-enriched algal biomass to fertilize crop soils. PMID:26795876

  12. Physiological responses of three marine microalgae exposed to cypermethrin.

    Science.gov (United States)

    Wang, Zhao-Hui; Nie, Xiang-Ping; Yue, Wen-Jie; Li, Xin

    2012-10-01

    The effects of cypermethrin on physiological responses of three typical marine microalgal species Skeletonema costatum (Bacillariophyceae), Scrippsiella trochoidea (Dinophyceae), and Chattonella marina (Raphidophyceae), were investigated by 96-h growth tests in a batch-culture system. The 96-h median inhibition concentrations (IC(50)) were 71.4, 205, and 191 μg L(-1) for S. costatum, S. trochoidea, and C. marina, respectively. Quick and significant physiological responses occurred when algal cells were exposed to cypermethrin, and all biochemical parameters varied significantly within 6- or 12-h exposure. Cypermethrin affected algal growth, protein content, and superoxide dismutase (SOD) activity by stimulation at low concentrations (1, 5 μg L(-1)) and inhibition at high concentrations (>50 μg L(-1)). A general increase in malondialdehyde (MDA) level was observed in all test groups, which suggested that the toxic effects of cypermethrin were probably exerted through free radical generation. These results suggest that the activation of SOD and promotion of protein at early exposure are important to counteract the oxidative stress induced by cypermethrin, and the inactivation of SOD may be crucial to the growth inhibition of microalgae by cypermethrin. PMID:21374785

  13. Antifouling potential of the marine microalga Dunaliella salina.

    Science.gov (United States)

    Gao, Min; Li, Fengchao; Su, Rongguo; Wang, Ke; Li, Xuzhao; Lu, Wei

    2014-11-01

    Marine organisms have usually been viewed as sources of environmentally friendly compounds with antifouling activity. We performed a series of operations to investigate the antifouling potential of the marine microalga Dunaliella salina. For the ethyl acetate crude extract, the antialgal activity was significant, and the EC50 value against Skeletonema costatum was 58.9 μg ml(-1). The isolated purified extract was tested for antifouling activity, the EC 50 value against S. costatum was 21.2 μg ml(-1), and the LC50 against Balanus amphitrite larvae was 18.8 μg ml(-1). Subsequently, both UHR-TOF-MS and GC-MS were used for the structural elucidation of the compounds, and a series of unsaturated and saturated 16- and 18-carbon fatty acids were detected. The data suggested that the fatty acid extracts from D. salina possess high antifouling activity, and could be used as substitutes for potent, toxic antifouling compounds. PMID:25096202

  14. Microalga Scenedesmus obliquus as a potential source for biodiesel production

    Energy Technology Data Exchange (ETDEWEB)

    Mandal, Shovon; Mallick, Nirupama [Indian Inst. of Technology, Kharagpur, West Bengal (India). Agricultural and Food Engineering Dept.

    2009-08-15

    Biodiesel from microalgae seems to be the only renewable biofuel that has the potential to completely replace the petroleum-derived transport fuels. Therefore, improving lipid content of microalgal strains could be a cost-effective second generation feedstock for biodiesel production. Lipid accumulation in Scenedesmus obliquus was studied under various culture conditions. The most significant increase in lipid reached 43% of dry cell weight (dcw), which was recorded under N-deficiency (against 12.7% under control condition). Under P-deficiency and thiosulphate supplementation the lipid content also increased up to 30% (dcw). Application of response surface methodology in combination with central composite rotary design (CCRD) resulted in a lipid yield of 61.3% (against 58.3% obtained experimentally) at 0.04, 0.03, and 1.0 g l{sup -1} of nitrate, phosphate, and sodium thiosulphate, respectively for time culture of 8 days. Scenedesmus cells pre-grown in glucose (1.5%)-supplemented N 11 medium when subjected to the above optimized condition, the lipid accumulation was boosted up to 2.16 g l{sup -1}, the value {proportional_to}40-fold higher with respect to the control condition. The presence of palmitate and oleate as the major constituents makes S. obliquus biomass a suitable feedstock for biodiesel production. (orig.)

  15. Modeling Growth of Microalgae Dunaliella Salina under Different Nutritional Conditions

    Directory of Open Access Journals (Sweden)

    Sergio S. Jesus

    2010-01-01

    Full Text Available Problem statement: The aim of this study was to find the empirical model that describes the growth kinetics of Dunaliella salina, with low production cost and to estimate parameters of this model. Approach: In this study the strain of D. salina UTEX 200 was cultivated in seawater (0.5 M NaCl at room temperature with agitation of 150 rpm and luminous intensity of 60 mmols.m-2.s-1. The synthetic medium AS100 (0.2 M NaCl was used in this study for comparison purposes and in order to determine the optimal growth of the microalgae. Kinetics of growth and â-carotene production was determined in a period of 15 days. Results: After the analysis of the behavior graphic, an unstructured model was used for describing the cell growth (logistic model. It was observed that the model was well adjusted to experimental data for the two conditions of analysis. It was observed that alga produces carotenoids under conditions of stress, in which the cell division are retarded. In the case of cells grown in seawater (higher salt concentration, the cell growth was lower but the concentration of â-carotene was higher. Conclusion: In general, these results suggest that D. salina presents higher potential for â-carotene accumulation and that high salinity decreases cellular concentration (measured by the parameter Xm of the kinetic model proposed; however there is an increase in â-carotene production.

  16. Microalgae cultivation as tertiary unit operation for treatment of pharmaceutical wastewater associated with lipid production.

    Science.gov (United States)

    Hemalatha, Manupati; Venkata Mohan, S

    2016-09-01

    Microalgae based treatment was studied to polish sequential batch reactor (SBR) treated pharmaceutical wastewater under mixotrophic mode of operation with simultaneous biomass/lipid production. At the end of biomass growth phase (BGP), carbon removal efficiency was observed to be 73% along with good removal of nitrates (62%). Since microalgae assimilate nutrients from wastewater for growth, an increment in total biomass productivity (2.8g/l) was observed. Subjecting to nutrient stress phase (NSP), total lipid content of 17.2% with neutral lipids of 6.2% was observed under light condition. Contrarily, dark condition depicted total lipid content of 15.8% with neutral lipids constituting 6.5%. The nutrient stress in combination with light showed marked influence on the profile of saturated and unsaturated fatty acids. Integration of microalgae cultivation improves environmental sustainability and enables greener routes of biofuels and value added products synthesis in a biorefinery approach. PMID:27177715

  17. Screening for lipid yielding microalgae: activities for 1983. Final subcontract report

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, W. H.; Tornabene, T. G.; Weissman, J.

    1984-04-01

    The SERI/DOE Aquatic Species Program is conducting a screening project, to select microalgae species and strains that are acceptable for liquid fuel production in outdoor culture. The emphases are on finding species that grow rapidly at high biomass density, in outdoor culture and produce large quantities of lipids. During 1983 over 100 species were isolated from saline waters at the California and Nevada deserts. Some of these species were characterized for growth response to various nutrients, temperatures, and salinities. Selected species were analyzed for lipid composition. Lipids were characterized into fractions, hydrocarbons, isoprenoids, triglyceride, glycolipids, and phospholipids. The most promising species were tested for growth and monoculture sustainability in outdoor culture. Each section (microalgae selection, chemical profiles of microalgae, mass culture of macroalgae) was abstracted separately. 51 references, 8 figures, 14 tables.

  18. Phosphopantetheinylation in the green microalgae Chlamydomonas reinhardtii

    DEFF Research Database (Denmark)

    Sonnenschein, Eva; Pu, Yuan; Beld, Joris;

    2016-01-01

    is responsible for holding the product. Fatty acid biosynthesis is initiated through posttranslational modification of the ACP by the phosphopantetheinyl transferase (PPTase). We identified two PPTases, PptC1 and PptC2, in the model alga Chlamydomonas reinhardtii by genome analysis and phylogenetic...... of the type II FAS, while PptC2 also recognized ACP of Escherichia coli type II FAS and actinorhodin type II polyketide synthase. Besides FAS as PPTase target, the C. reinhardtii genome encodes a single type I PKS, and we hypothesize that PptC2 is responsible for its activation. Screening of the currently...... in microalgae shows that microalgae are already primed for biotechnological applications in contrast to other organisms. Thus, microalgae have great potential for metabolic engineering efforts in the realm of biofuel and high-value products including direct engineering of the fatty acid or secondary metabolism...

  19. Bioprocess engineering of microalgae to produce a variety of consumer products

    Energy Technology Data Exchange (ETDEWEB)

    Harun, Razif [Bio Engineering Laboratory (BEL), Department of Chemical Engineering, Monash University, Victoria 3800 (Australia); Department of Chemical and Environmental Engineering, Universiti Putra Malaysia, 43400 Serdang (Malaysia); Singh, Manjinder; Forde, Gareth M.; Danquah, Michael K. [Bio Engineering Laboratory (BEL), Department of Chemical Engineering, Monash University, Victoria 3800 (Australia)

    2010-04-15

    Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. (author)

  20. Antibacterial Activity of Freshwater Microalga Scenedesmus sp. on Foodborne Pathogens Staphylococcus aureus and Salmonella sp.

    Directory of Open Access Journals (Sweden)

    Aisha Gogoba Ishaq

    2016-01-01

    Full Text Available Microalgae possess promising bioactive compounds with a wide range of activities. In this study, crude pigment extract of Scenedesmus sp. a freshwater microalga was screened against two known foodborne pathogens Staphylococcus aureus (ATCC 25923 and Salmonella sp. (ATCC 14028 to evaluate its antimicrobial properties. The crude pigment of the microalga was extracted with 90 % acetone whereas antibacterial screening was done by agar well diffusion method. In addition, the MIC of crude pigment was determined following the macrobroth dilution method. Concentrations ranging from 0.35mg/ml – 3.48 mg/ml demonstrated highest inhibitory activity against Staphylococcus aureus (ATCC 25923.  The MIC was achieved at 0.08 mg/ ml. On the other hand, there was no inhibitory activity at any concentration of crude extract against Salmonella sp. (ATCC 14028.  Results of this study suggest that the inhibitory activity may be limited to gram positive foodborne pathogen Staphylococcus aureus.

  1. Bioprocess engineering of microalgae to produce a variety of consumer products

    International Nuclear Information System (INIS)

    Microalgae biotechnology has recently emerged into the lime light owing to numerous consumer products that can be harnessed from microalgae. Product portfolio stretches from straightforward biomass production for food and animal feed to valuable products extracted from microalgal biomass, including triglycerides which can be converted into biodiesel. For most of these applications, the production process is moderately economically viable and the market is developing. Considering the enormous biodiversity of microalgae and recent developments in genetic and metabolic engineering, this group of organisms represents one of the most promising sources for new products and applications. With the development of detailed culture and screening techniques, microalgal biotechnology can meet the high demands of food, energy and pharmaceutical industries. This review article discusses the technology and production platforms for development and creation of different valuable consumer products from microalgal biomass. (author)

  2. TOR (target of rapamycin) is a key regulator of triacylglycerol accumulation in microalgae.

    Science.gov (United States)

    Imamura, Sousuke; Kawase, Yasuko; Kobayashi, Ikki; Shimojima, Mie; Ohta, Hiroyuki; Tanaka, Kan

    2016-01-01

    Most microalgae abundantly accumulate lipid droplets (LDs) containing triacylglycerols (TAGs) under several stress conditions, but the underlying molecular mechanism of this accumulation remains unclear. In a recent study, we found that inhibition of TOR (target of rapamycin), a highly conserved protein kinase of eukaryotes, by rapamycin resulted in TAG accumulation in microalgae, indicating that TOR negatively regulates TAG accumulation. Here, we show that formation of intracellular LDs and TAG accumulation were also induced in the unicellular green alga Chlamydomonas reinhardtii after exposure to Torin1 or AZD8055, which are novel TOR inhibitors that inhibit TOR activity in a manner different from rapamycin. These results supported quite well our previous conclusion that TOR is a central regulator of TAG accumulation in microalgae.

  3. Heavy metal removal from acid mine drainage by calcined eggshell and microalgae hybrid system.

    Science.gov (United States)

    Choi, Hee-Jeong; Lee, Seung-Mok

    2015-09-01

    This study investigates the use of calcined eggshells and microalgae for the removal of heavy metals from acid mine drainage (AMD) and the simultaneous enhancement of biomass productivity. The experiment was conducted over a period of 6 days in a hybrid system containing calcined eggshells and the microalgae Chlorella vulgaris. The results show that the biomass productivity increased to ~8.04 times its initial concentration of 0.367 g/L as measured by an optical panel photobioreactor (OPPBR) and had a light transmittance of 95 % at a depth of 305 mm. On the other hand, the simultaneous percent removal of Fe, Cu, Zn, Mn, As, and Cd from the AMD effluent was found to be 99.47 to 100 %. These results indicate that the hybrid system with calcined eggshells and microalgae was highly effective for heavy metal removal in the AMD.

  4. Carotenoids from Marine Microalgae: A Valuable Natural Source for the Prevention of Chronic Diseases

    Directory of Open Access Journals (Sweden)

    Maria Filomena de Jesus Raposo

    2015-08-01

    Full Text Available Epidemiological studies have shown a relation between antioxidants and the prevention of several chronic diseases. Microalgae are a potential novel source of bioactive molecules, including a wide range of different carotenoids that can be used as nutraceuticals, food supplements and novel food products. The objective of this review is (i to update the research that has been carried out on the most known carotenoids produced by marine microalgae, including reporting on their high potentialities to produce other less known important compounds; (ii to compile the work that has been done in order to establish some relationship between carotenoids and oxidative protection and treatment; (iii to summarize the association of oxidative stress and the various reactive species including free radicals with several human diseases; and (iv to provide evidence of the potential of carotenoids from marine microalgae to be used as therapeutics to treat or prevent these oxidative stress-related diseases.

  5. Development of a Biosensor for Environmental Monitoring Based on Microalgae Immobilized in Silica Hydrogels

    Directory of Open Access Journals (Sweden)

    Claude Durrieu

    2012-12-01

    Full Text Available A new biosensor was designed for the assessment of aquatic environment quality. Three microalgae were used as toxicity bioindicators: Chlorella vulgaris, Pseudokirchneriella subcapitata and Chlamydomonas reinhardtii. These microalgae were immobilized in alginate and silica hydrogels in a two step procedure. After studying the growth rate of entrapped cells, chlorophyll fluorescence was measured after exposure to (3-(3,4-dichlorophenyl-1,1-dimethylurea (DCMU and various concentrations of the common herbicide atrazine. Microalgae are very sensitive to herbicides and detection of fluorescence enhancement with very good efficiency was realized. The best detection limit was 0.1 µM, obtained with the strain C. reinhardtii after 40 minutes of exposure.

  6. Co-cultivation of microalgae and nitrifiers for higher biomass production and better carbon capture.

    Science.gov (United States)

    Bilanovic, Dragoljub; Holland, Mark; Starosvetsky, Jeanna; Armon, Robert

    2016-11-01

    The aim of this work was to study co-cultivation of nitrifiers with microalgae as a non-intrusive technique for selective removal of oxygen generated by microalgae. Biomass concentration was, at least, 23% higher in mixed-cultures where nitrifiers kept the dissolved oxygen concentration below 9.0μLL(-1) than in control Chlorella vulgaris axenic-cultures where the concentration of dissolved oxygen was higher than 10.0μLL(-1). This approach to eliminating oxygen inhibition of microalgal growth could become the basis for the development of advanced microalgae reactors for removal of CO2 from the atmosphere, and concentrated CO2 streams. CO2 sequestration would become a chemically and geologically safer and environmentally more sound technology provided it uses microalgal, or other biomass, instead of CO2, for carbon storage. PMID:27584904

  7. Regulation of starch and lipid accumulation in a microalga Chlorella sorokiniana.

    Science.gov (United States)

    Li, Tingting; Gargouri, Mahmoud; Feng, Jie; Park, Jeong-Jin; Gao, Difeng; Miao, Chao; Dong, Tao; Gang, David R; Chen, Shulin

    2015-03-01

    Microalgae have attracted growing attention due to their potential in biofuel feedstock production. However, current understanding of the regulatory mechanisms for lipid biosynthesis and storage in microalgae is still limited. This study revealed that the microalga Chlorella sorokiniana showed sequential accumulation of starch and lipids. When nitrogen was replete and/or depleted over a short period, starch was the predominant carbon storage form with basal levels of lipid accumulation. After prolonged nitrogen depletion, lipid accumulation increased considerably, which was partially due to starch degradation, as well as the turnover of primary metabolites. Lipid accumulation is also strongly dependent on the linear electron flow of photosynthesis, peaking at lower light intensities. Collectively, this study reveals a relatively clear regulation pattern of starch and lipid accumulation that is basically controlled by nitrogen levels. The mixotrophic growth of C. sorokiniana shows promise for biofuel production in terms of lipid accumulation in the final biomass.

  8. Co-cultivation of microalgae and nitrifiers for higher biomass production and better carbon capture.

    Science.gov (United States)

    Bilanovic, Dragoljub; Holland, Mark; Starosvetsky, Jeanna; Armon, Robert

    2016-11-01

    The aim of this work was to study co-cultivation of nitrifiers with microalgae as a non-intrusive technique for selective removal of oxygen generated by microalgae. Biomass concentration was, at least, 23% higher in mixed-cultures where nitrifiers kept the dissolved oxygen concentration below 9.0μLL(-1) than in control Chlorella vulgaris axenic-cultures where the concentration of dissolved oxygen was higher than 10.0μLL(-1). This approach to eliminating oxygen inhibition of microalgal growth could become the basis for the development of advanced microalgae reactors for removal of CO2 from the atmosphere, and concentrated CO2 streams. CO2 sequestration would become a chemically and geologically safer and environmentally more sound technology provided it uses microalgal, or other biomass, instead of CO2, for carbon storage.

  9. Microalgae pretreatment with liquid hot water to enhance enzymatic hydrolysis efficiency.

    Science.gov (United States)

    Yuan, Tao; Li, Xiekun; Xiao, Shiyuan; Guo, Ying; Zhou, Weizheng; Xu, Jingliang; Yuan, Zhenhong

    2016-11-01

    Nowadays, microalgae are being considered as promising raw material for bioethanol production. In this work, three process variables during liquid hot water (LHW) pretreatment prior to enzymatic hydrolysis by response surface methodology on Scenedesmus sp. WZKMT were investigated to enhance glucose recovery. Results indicated that the order of significance for three parameters was temperature>solid-to-liquid ratio>time. The optimal condition was 1:13 (w/v), 147°C and 40min. The concentration and recovery of glucose under this condition were 14.223g·L(-1) and 89.32%, respectively, which were up to 5-fold higher than the samples without LHW pretreatment. In addition, the surface morphologies of microalgae cells before and after LHW pretreatment were also verified using scanning electron microscopy (SEM). LHW pretreatment can greatly enhance the enzymatic efficiency, and can be regarded as an ideal pretreatment method for glucose recovery from microalgae. PMID:27614155

  10. Neutral lipid accumulation at elevated temperature in conditional mutants of two microalgae species

    DEFF Research Database (Denmark)

    Yao, Shuo; Brandt, Anders Bøving; Egsgaard, Helge;

    2012-01-01

    Triacylglycerols, an energy storage compound in microalgae, are known to be accumulated after nitrogen starvation of microalgae cells. Microalgae could be of importance for future biodiesel production due to their fast growth rate and high oil content. In collections of temperature sensitive...... mutants of Chlamydomonas reinhardtii and Chlorella vulgaris, nine out of fourty-one mutants in C. reinhardtii and eleven out of fifty-three mutants in C. vulgaris contained increased amounts of neutral lipids, predominantly as triacylglycerols. Upon temperature induced cell-cycle arrest, these mutants...... showed enlarged cellular volume compared with the wild type. The C. reinhardtii mutants were analyzed further and one type of mutants displayed a shift in lipid composition from polar membrane lipids to neutral lipids after a temperature up-shift, while the second type of mutants accumulated more total...

  11. Biosequestration of atmospheric CO2 and flue gas-containing CO2 by microalgae.

    Science.gov (United States)

    Cheah, Wai Yan; Show, Pau Loke; Chang, Jo-Shu; Ling, Tau Chuan; Juan, Joon Ching

    2015-05-01

    The unceasing rise of greenhouse gas emission has led to global warming and climate change. Global concern on this phenomenon has put forward the microalgal-based CO2 sequestration aiming to sequester carbon back to the biosphere, ultimately reducing greenhouse effects. Microalgae have recently gained enormous attention worldwide, to be the valuable feedstock for renewable energy production, due to their high growth rates, high lipid productivities and the ability to sequester carbon. The photosynthetic process of microalgae uses atmospheric CO2 and CO2 from flue gases, to synthesize nutrients for their growth. In this review article, we will primarily discuss the efficiency of CO2 biosequestration by microalgae species, factors influencing microalgal biomass productions, microalgal cultivation systems, the potential and limitations of using flue gas for microalgal cultivation as well as the bio-refinery approach of microalgal biomass.

  12. Development of a biosensor for environmental monitoring based on microalgae immobilized in silica hydrogels.

    Science.gov (United States)

    Ferro, Yannis; Perullini, Mercedes; Jobbagy, Matias; Bilmes, Sara A; Durrieu, Claude

    2012-01-01

    A new biosensor was designed for the assessment of aquatic environment quality. Three microalgae were used as toxicity bioindicators: Chlorella vulgaris, Pseudokirchneriella subcapitata and Chlamydomonas reinhardtii. These microalgae were immobilized in alginate and silica hydrogels in a two step procedure. After studying the growth rate of entrapped cells, chlorophyll fluorescence was measured after exposure to (3-(3,4-dichlorophenyl)-1,1-dimethylurea) (DCMU) and various concentrations of the common herbicide atrazine. Microalgae are very sensitive to herbicides and detection of fluorescence enhancement with very good efficiency was realized. The best detection limit was 0.1 µM, obtained with the strain C. reinhardtii after 40 minutes of exposure. PMID:23223083

  13. Evolución del contenido en particulas totales en suspensión y en los metales, plomo, cinc, cadmio, cobre, hierro y manganeso, en el aerosol atmosferico de Cartagena, durante el periodo 1995-2000

    OpenAIRE

    Martínez Arroyo, María C.

    2009-01-01

    El análisis del aerosol atmosférico es uno de los campos básicos en los estudios medioambientales, principalmente por sus efectos sobre la salud humana y su papel en el cambio climático. La ciudad de Cartagena, por sus características geográficas, tiene una historia minera e industrial importante que ha repercutido notablemente en su medio ambiente. El estudio de su aerosol es esencial para poder valorar la evolución del mismo a lo largo del tiempo, su situación frente a la legislación actual...

  14. Biomass and Oil Production of Green Microalgae Scenedesmus sp. Using Different Nutrients and Growth

    Directory of Open Access Journals (Sweden)

    Prof. dr. Violeta Makareviciene

    2013-01-01

    Full Text Available Biofuel is mostly produced from oleaginous crops, such as rapeseed, sunflower, soybean. The search for new technologies and new feedstock for biofuel production is becoming an increasingly important issue for researchers. Special attention is turned to the raw materials which do not compete with food industry. Microalgae ability, due to their rapid growth, to accumulate oil, to treat wastewater and waste, seems to be a very attractive new object to be used for biofuel production. In this study we have investigated different microalgae growth conditions, including both autotrophic cultivation by means of nitrogen deprivation mode and mixotrophic cultivation by applying liquid waste and technical glycerol for determining the best growth and oil production conditions. It is found that applying nitrogen deprivation mode and mixotrophic growth conditions, microalgae Scenedesmus sp. have grown faster and accumulation of their oil has increased 10.88 times compared to that under autotrophic growth conditions using the usual amount of nitrogen. The highest biomass concentration (2.16 gL-1 is obtained by adding 5 gL-1 glycerol into the growth medium, whereas the highest oil concentration (15.12 % is reached when using 10 gL-1 technical glycerol. In addition, the elemental composition of microalgae biomass has been analyzed. Results indicate that the usage of glycerol for cultivation of microalgae increases C : N ratio to optimum (19.25 for biogas production, and algae biomass could be used for this biofuel production without adding any other co-substratum. The results of our study show that addition of cheap products: liquid waste and technical glycerol can effectively adjust the composition of microalgae biomass, making it more suitable for biofuel production.DOI: http://dx.doi.org/10.5755/j01.erem.62.4.2318

  15. Potential of Local Microalgae as A Natural Antioxidant to Produce Asuh Broiler Meat

    Directory of Open Access Journals (Sweden)

    Salvia Salvia

    2013-01-01

    Full Text Available Feed quality for food safety. To produce ASUH (safe, healthy, whole and halal food from  broiler , it should be fed with quality ration that free from chemical residues derived from synthetic antioxidants such as BHT, BHA and antibiotic for the meat  contained  residue that will cause negative effect.  Microalgae has the potential to be used as natural supplement because it contains nutrients, antioxidant,  cholesterolemic effect and plant growth regulator. Ojectives of this study is to  exploit natural antioxidant substance in local microalgae extract as  natural supplement for broiler.  This research used local microalgae collected from water of the pond located around chicken farm in Nagari Mungka, 50 Kota District. DPPH free radical absorbance method used to test antioxidant activity, while ascorbic acid (Vitamin C used as comparison, and was tested to broiler to oversee its performance.  Best concentration tested to broilers and its performances was observed.  The result of study ; Local microalgae extract  has ability to inhibit DPPH free radical  by  concentration at 80 mg/ml  which is equal to 6 mg/ml   of Vitamin C. The performance  after giving  microalgae as antioxidant is better than Vitamin C because it contains nutrition and others secondary metabolic  such as antimicrobial, cholesterolimic effect and plant growth regulator. Local microalgae is potential as source of natural antioxidants for producing ASUH broiler meat

  16. The Costs of Producing Biodiesel from Microalgae in the Asia-Pacific Region

    Directory of Open Access Journals (Sweden)

    G.J. Griffin

    2013-10-01

    Full Text Available Capital and operating cost estimates for converting microalgae to oil or biodiesel are compared. These cost comparisons are based on Australian locations, which are expected to fall at the lower end of the cost spectrum in the Asia-Pacific Region and other parts of the world.  It is assumed that microalgae are grown in a concentrated saltwater medium in raceway ponds, then are harvested, dewatered and the oil is extracted and converted to biodiesel by transesterification. The size of the desired pond system affects the number of potential locations due to constraints in resource availability. Cost estimates vary significantly due to differences in the assumed oil productivity, the harvesting equipment and the method of converting residual biomass to electric power. A comparison is made with recent cost estimates from other parts of the world, in which the expected costs of microalgae oil production from a number of publicly available sources lay between 0.34–31.0 USD/L.  The resulting cost estimates of between 1.37—2.66 USD/L are at the lower end of this scale, thereby confirming that Australia has the potential to be a low-cost producer of algal oil and biodiesel in the Asia-Pacific Region.  It was significant that, despite similar assumptions for the microalgae-to-oil process, cost estimates for the final biodiesel or oil price differed by a factor of 2.  This highlights the high degree of uncertainty in such economic predictions. Keywords: Asia-Pacific region; biodiesel; economics; microalgaeThis article is cited as :Griffin, G., Batten, D., Beer, T., & Campbell, P. (2013. The Costs of Producing Biodiesel from Microalgae in the Asia-Pacific Region. International Journal Of Renewable Energy Development (IJRED, 2(3, 105-113. doi:10.14710/ijred.2.3.105-113Permalinkhttp://dx.doi.org/10.14710/ijred.2.3.105-113

  17. Sobre la muerte voluntaria

    Directory of Open Access Journals (Sweden)

    Juan Álvarez-Cienfuegos Fidalgo

    2012-03-01

    Full Text Available El problema de cómo morir en nuestra sociedad se ha convertido en una inquietud para los ciudadanos y la reflexión moral. Especialmcnte por dos razones: por el desarrollo de la tecnología médica y por el hecho de que la mayor parte de los fallecimientos tienen lugar fuera del hogar, donde tradicionalmente ocurra el deceso. El presente artículo tiene como objetivo acercarse a esta cuestión. Para ello, se parte de la autonomía del ciudadano, con derecho a decidir sobre lo que considera cuál sea su manera de vivir y de morir. A tal fin, se hace una breve introducción sobre el dolor, el suicidio y la muerte, desde un punto de vista antropológico, pasando, después, a mostrar las cuestiones relacionadas con el problema de la eutanasia, donde la atención se dirigirá, ante todo, al enjuiciamiento crítico del tenso equilibrio en el que se mantienen dos principios fundamentales de la bioética: el de no maleficencia y el de autonomía del ciudadano.The problem of how to die in modern society has become a concern for both the citizen and moral reflection for two reasons in particular: due to developments in medical technology, and because most deaths occur outside the honre, where they traditionaÍlY took place. This paper addresses this issue, starting from citizen autonomy, the right to decide on what s/he considers to be his or her way of living and dying. To this end, a brief introduction considers pain, suicide and death from an anthropological viewpoint. Questions related to the problem of euthanasia are then exposed, with particular attention to, above all the critical judgement of the tense balance in which two fundamental principies of bioethics are held, the principle of non-maleficence and that of citizen autonomy.

  18. Direct Biodiesel Production from Wet Microalgae Biomass of Chlorella pyrenoidosa through In Situ Transesterification

    OpenAIRE

    Hechun Cao; Zhiling Zhang; Xuwen Wu; Xiaoling Miao

    2013-01-01

    A one-step process was applied to directly converting wet oil-bearing microalgae biomass of Chlorella pyrenoidosa containing about 90% of water into biodiesel. In order to investigate the effects of water content on biodiesel production, distilled water was added to dried microalgae biomass to form wet biomass used to produce biodiesel. The results showed that at lower temperature of 90°C, water had a negative effect on biodiesel production. The biodiesel yield decreased from 91.4% to 10.3% a...

  19. Effect of Temperature on the Fatty Acid Composition of Four Species of Marine Microalgae

    Institute of Scientific and Technical Information of China (English)

    Li Wenquan; Li Qian; Liao Qibin; Chen Qinghua

    2003-01-01

    The GC analysis of fatty acid of four species of marine microalgae cultured at different temperature shows that the temperature has distinct effects on the composition and unsaturated degree of fatty acid of microalgae. The percentages of TPUFA in TFA and the number of mean double-bond of fatty acids ot Isochrysis galbana, Dunaliella salina and Phaeodactylum tricornutum decrease with the ascending temperature, while those of TMUFA and TSFA increase under the conditions of the present experiment. The content of TPUFA and the number of mean double-bonds of Chlorella sp. first decrease and then increase, with the minimum occurring at 20℃.

  20. The Costs of Producing Biodiesel from Microalgae in the Asia-Pacific Region

    OpenAIRE

    Griffin, G. J.; D F Batten; De Beer, T.; Campbell, P.K.

    2013-01-01

    Capital and operating cost estimates for converting microalgae to oil or biodiesel are compared. These cost comparisons are based on Australian locations, which are expected to fall at the lower end of the cost spectrum in the Asia-Pacific Region and other parts of the world.  It is assumed that microalgae are grown in a concentrated saltwater medium in raceway ponds, then are harvested, dewatered and the oil is extracted and converted to biodiesel by transesterification. The size of the desi...

  1. Biodiesel from microalgae Chlorella protothecoides growing at autotrophic and heterotrophic metabolisms in a new symbiotic bioreactor

    OpenAIRE

    Santos, Carla A.; Reis, Alberto

    2013-01-01

    Biodiesel is an alternative energy to fossil fuels, and is produced from biomass, therefore provides lower CO2 emissions. Currently, biodiesel is produced from plant oils, animal fats and used oils. These sources are low-yield which is a limitation to the production of biodiesel in large quantities. On the contrary, microalgae present a very high yield and can be produced in large amounts. The bio-refinery of microalgae oil must have a strategy of taking advantage of all by-products to make ...

  2. Optimal design of microalgae-based biorefinery: Economics, opportunities and challenges

    DEFF Research Database (Denmark)

    Rizwan, Muhammad; Lee, Jay H.; Gani, Rafiqul

    2015-01-01

    Microalgae have great potential as a feedstock for the production of a wide range of end-products under the broad concept of biorefinery. In an earlier work, we proposed a superstructure based optimization model to find the optimal processing pathway for the production of biodiesel from microalgal...... biomass, and identified several challenges with the focus being on utilizing lipids extracted microalgal biomass for economic and environmentally friendly production of useful energy products. In this paper, we expand the previous optimization framework by considering the processing of microalgae residue...

  3. Highly oil-producing microalgae selected through directed-evolution on a microfludic chip

    Science.gov (United States)

    Mestler, Troy; Estevez-Torres, Andre; Lambert, Guillaume; Austin, Robert H.

    2009-03-01

    Some species of photosynthetic microalgae produce signi?cant amounts of oil which can be easily converted to diesel fuel. However, as it stands today, biodiesel is signi?cantly more expensive than fossil fuels. We wish to improve the oil yield and production rate of a single species of microalgae through directed evolution. We propose to utilize our microfabication technology to create microhabitats to control the nutrient environment of the species, monitor oil production through Raman Spectroscopy, and punish colonies of algae which have low oil yield. We believe this process will produce a mutant species with a high oil yield.

  4. Sobre el nombre "Quechua"

    Directory of Open Access Journals (Sweden)

    Rodolfo Cerrón-Palomino

    1985-06-01

    Full Text Available Uno de los primeros problemas con el que a menudo tropiezael estudioso de los idiomas ágrafos, como es el caso de las lenguasaborígenes de América, es el de su denominación (glotónimo.En la medida ,en que, por razones históricas, las noticias sobretales lenguas, y por consiguiente los primeros estudios sobre lasmismas, surgen a partir del contacto con los miembros de la civilización occidental, los nombres de los distintos idiomas, así comode los grupos étnicos que los manejan, son el resultado casi siempre arbitrario cie designaciones fortuitas hechas por viajeros, misiioneros y exploradores, quienes por lo general se basan, para ello, bien en descripciones físicas de los grupo étnicos, en ciertos indios geográficos que constituyen el habitat de los mismos, e incluso en prejuicios que se nutren de un marcado europocentrismo.

  5. Refletindo sobre idosos institucionalizado

    Directory of Open Access Journals (Sweden)

    Cenir Gonçalves Tier

    2004-06-01

    Full Text Available Trata-se de uma pesquisa qualitativa, descritiva que teve por objetivo identificar como vem sendo o relacionamento idoso-família, identificando os motivos que levaram os familiares a optarem pela institucionalização do seu idoso, obtendo-se também a visão da família sobre o cuidado no lar. Para coleta dos dados utilizou-se um instrumento com perguntas abertas. A coleta dos dados efetivou-se nos meses de agosto de 2002 a julho de 2003, sendo sujeitos da pesquisa, familiares de idosos de uma instituição asilar em um município da região noroeste do Rio Grande do Sul. Através da análise de conteúdo constatou-se que a maior dificuldade encontrada pela família, visando dispensar cuidados ao idoso é a "falta de tempo para cuidar" do seu familiar idoso, pois a maioria deles exige cuidados em tempo integral.

  6. Microalgae consortia cultivation in dairy wastewater to improve the potential of nutrient removal and biodiesel feedstock production.

    Science.gov (United States)

    Qin, Lei; Wang, Zhongming; Sun, Yongming; Shu, Qing; Feng, Pingzhong; Zhu, Liandong; Xu, Jin; Yuan, Zhenhong

    2016-05-01

    The potential of microalgae consortia used in dairy wastewater treatment combined with microalgae biodiesel feedstock production was evaluated by comparing the nutrient removal of dairy wastewater, the growth of cells, and the lipid content and composition of biomass between monoalgae and microalgae consortia cultivation system. Our results showed that higher chemical oxygen demand (COD) removal (maximum, 57.01-62.86 %) and total phosphorus (TP) removal (maximum, 91.16-95.96 %) were achieved in almost microalgae consortia cultivation system than those in Chlorella sp. monoalgae cultivation system (maximum, 44.76 and 86.74 %, respectively). In addition, microalgae consortia cultivation except the mixture of Chlorella sp. and Scenedesmus spp. reached higher biomass concentration (5.11-5.41 g L(-1)), biomass productivity (730.4-773.2 mg L(-1) day(-1)), and lipid productivity (143.7-150.6 mg L(-1) day(-1)) than those of monoalgae cultivation (4.72 g L(-1), 674.3, and 142.2 mg L(-1) day(-1), respectively) on the seventh day. Furthermore, the fatty acid methyl ester (FAME) profiles indicated the lipids produced from microalgae consortia cultivation system were more suitable for biodiesel production. The microalgae consortia display superiority in dairy wastewater treatment and the getting feedstock for biodiesel production. PMID:26780059

  7. A Label-Free Microfluidic Biosensor for Activity Detection of Single Microalgae Cells Based on Chlorophyll Fluorescence

    Directory of Open Access Journals (Sweden)

    Junsheng Wang

    2013-11-01

    Full Text Available Detection of living microalgae cells is very important for ballast water treatment and analysis. Chlorophyll fluorescence is an indicator of photosynthetic activity and hence the living status of plant cells. In this paper, we developed a novel microfluidic biosensor system that can quickly and accurately detect the viability of single microalgae cells based on chlorophyll fluorescence. The system is composed of a laser diode as an excitation light source, a photodiode detector, a signal analysis circuit, and a microfluidic chip as a microalgae cell transportation platform. To demonstrate the utility of this system, six different living and dead algae samples (Karenia mikimotoi Hansen, Chlorella vulgaris, Nitzschia closterium, Platymonas subcordiformis, Pyramidomonas delicatula and Dunaliella salina were tested. The developed biosensor can distinguish clearly between the living microalgae cells and the dead microalgae cells. The smallest microalgae cells that can be detected by using this biosensor are 3 μm ones. Even smaller microalgae cells could be detected by increasing the excitation light power. The developed microfluidic biosensor has great potential for in situ ballast water analysis.

  8. Probing the elastic response of microalga Scenedesmus dimorphus in dry and aqueous environments through atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Warren, K. M.; Mpagazehe, J. N.; Higgs, C. F., E-mail: prl@andrew.cmu.edu, E-mail: higgs@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); LeDuc, P. R., E-mail: prl@andrew.cmu.edu, E-mail: higgs@andrew.cmu.edu [Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213 (United States); Departments of Biomedical Engineering and Biological Sciences, Carnegie Mellon University, 5000 Forbes Ave., Pittsburgh, Pennsylvania 15213 (United States)

    2014-10-20

    With the re-emergence of microalgae as a replacement feedstock for petroleum-derived oils, researchers are working to understand its chemical and mechanical behavior. In this work, the mechanical properties of microalgae, Scenedesmus dimorphus, were investigated at the subcellular level to determine the elastic response of cells that were in an aqueous and dried state using nano-scale indentation through atomic force microscopy. The elastic modulus of single-celled S. dimorphus cells increased over tenfold from an aqueous state to a dried state, which allows us to better understand the biophysical response of microalgae to stress.

  9. Peracetic acid is a suitable disinfectant for recirculating fish-microalgae integrated multi-trophic aquaculture systems

    DEFF Research Database (Denmark)

    Liu, Dibo; Behrens, Sascha; Pedersen, Lars-Flemming;

    2016-01-01

    tIntegrated multi-trophic aquaculture (IMTA) is a promising direction for the sustainable developmentof aquaculture. Microalgae have good potential to be integrated with recirculating aquaculture sys-tems because they can use the nitrogen excreted from fish and share the same optimal pH value asin...... aquaculture. As a byproduct, the microalgae biomass can be used for fish feed or biofuel. How-ever, the recirculating fish-microalgae IMTA system is under constant threat from fish pathogens andphytoplankton-lytic bacteria. Therefore, it is necessary to apply proper disinfectants as prophylaxis ortreatment...

  10. Genetic engineering: a promising tool to engender physiological, biochemical and molecular stress resilience in green microalgae

    Directory of Open Access Journals (Sweden)

    Freddy eGuiheneuf

    2016-03-01

    Full Text Available As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest towards a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy to fix atmospheric CO2 into algal biomass, mitigating fossil CO2 pollution in the process. Remarkably, a feature innate to most microalgae is synthesis and accumulation of lipids (60–65% of dry weight, carbohydrates and secondary metabolites like pigments and vitamins, especially when grown under abiotic stress conditions. Particularly fruitful, such an application of abiotic stress factors like nitrogen starvation , salinity, heat shock etc. can be used in a biorefinery concept for production of multiple valuable products. The focus of this mini-review underlies metabolic reorientation practices and tolerance mechanisms as applied to green microalgae under specific stress stimuli for a sustainable pollution-free future. Moreover, we entail current progress on genetic engineering as a promising tool to grasp adaptive processes for improving strains with potential biotechnological interests.

  11. Enhancement of microalgae production by embedding hollow light guides to a flat-plate photobioreactor.

    Science.gov (United States)

    Sun, Yahui; Huang, Yun; Liao, Qiang; Fu, Qian; Zhu, Xun

    2016-05-01

    To offset the adverse effects of light attenuation on microalgae growth, hollow polymethyl methacrylate (PMMA) tubes were embedded into a flat-plate photobioreactor (PBR) as light guides. In this way, a fraction of incident light could be transmitted and emitted to the interior of the PBR, providing a secondary light source for cells in light-deficient regions. The average light intensity of interior regions 3-6cm from surfaces with 70μmolm(-2)s(-1) incident light was enhanced 2-6.5 times after 3.5days cultivation, resulting in a 23.42% increase in biomass production to that cultivated in PBR without PMMA tubes. The photosynthetic efficiency of microalgae in the proposed PBR was increased to 12.52%. Moreover, the installation of hollow PMMA tubes induced turbulent flow in the microalgae suspension, promoting microalgae suspension mixing. However, the enhanced biomass production was mainly attributed to the optimized light distribution in the PBR. PMID:26868153

  12. Mechanisms of flash pyrolysis of ether lipids isolated from the green microalga Botryococcus braunii race

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Gelin, F.; Gatellier, J-P.L.A.; Metzger, P.; Derenne, S.; Largeau, C.; Leeuw, J.W. de

    1993-01-01

    Two types of ether lipids isolated from the microalga Botryococcus braunii have been subjected to flash pyrolysis. The pyrolysis products were separated and analyzed by GC/MS. The nature and distribution of the pyrolysis compounds gave clues to the different mechanisms involved in the pyrolysis of e

  13. Life cycle costs for the optimized production of hydrogen and biogas from microalgae

    International Nuclear Information System (INIS)

    Despite the known advantages of microalgae compared with other biomass providers or fossil fuels, microalgae are predominately produced for high-value products. Economic constraints might limit the commercial energetic use of microalgae. Therefore, we identify the LCCs (life cycle costs) and economic hot spots for photoautotrophic hydrogen generation from photoautotrophically grown Chlamydomonas reinhardtii in a novel staggered PBR (photobioreactor) and the anaerobic digestion of the residual biomass to obtain biogas. The novel PBR aims at minimizing energy consumption for mixing and aeration and at optimizing the light conditions for algal growth. The LCCs per MJ amounted to 12.17 Euro for hydrogen and 0.99 Euro for biogas in 2011 for Germany. Market prices per MJ of 0.02 Euro for biogas and 0.04 Euro for hydrogen are considerably exceeded. Major contributors to operating costs, about 70% of total LCCs, are personnel and overhead costs. The investment costs consist to about 92% of those for the PBR with a share of 61% membrane costs. The choice of Madrid as another production location with higher incident solar irradiation and lower personnel costs reduces LCCs by about 40%. Projecting LCCs to 2030 with experience curves, the LCCs still exceed future market prices. - Highlights: • Life cycle cost assessment of hydrogen and biogas from microalgae in a novel photobioreactor. • Current and future (2030) economically viable production unlikely in Germany. • Personnel and photobioreactor costs are major cost drivers. • Changing the production location may significantly reduce the life cycle costs

  14. Effects of macro and micronutrients on neutral lipid accumulation in oleaginous microalgae

    NARCIS (Netherlands)

    Ghafari, Mohsen; Rashidi, Behzad; Haznedaroglu, Berat Zeki

    2016-01-01

    In this study, effects of key macro and micronutrients on neutral lipid accumulation of six oleaginous microalgae species were investigated. For each nutrient, three different concentrations (0.5×, 1×, and 2×) were tested individually and compared to the most commonly utilized growth medium recip

  15. Development of a Two-Stage Microalgae Dewatering Process - A Life Cycle Assessment Approach.

    Science.gov (United States)

    Soomro, Rizwan R; Ndikubwimana, Theoneste; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  16. Optimisation of cultivation parameters in photobioreactors for microalgae cultivation using the A-stat technique

    NARCIS (Netherlands)

    Barbosa, M.J.; Hoogakker, J.; Wijffels, R.H.

    2003-01-01

    Light availability inside the reactor is often the bottleneck in microalgal cultivation and for this reason much attention is being given to light limited growth kinetics of microalgae, aiming at the increase of productivity in photobioreactors. Steady-state culture characteristics are commonly used

  17. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Takashi Nakamura

    2004-11-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 April to 30 June 2004 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work during the previous reporting period, Aquasearch run further, pilot and full scale, carbon sequestration tests with actual propane combustion gases utilizing two different strains of microalgae. Aquasearch continued testing modifications to the coal combustor to allow for longer-term burns. Aquasearch also tested an alternative cell separation technology. University of Hawaii performed experiments at the Mera Pharmaceuticals facility in Kona in mid June to obtain data on the carbon venting rate out of the photobioreactor; gas venting rates were measured with an orifice flow meter and gas samples were collected for GC analysis to determine the carbon content of the vented gases.

  18. Genetic Engineering: A Promising Tool to Engender Physiological, Biochemical, and Molecular Stress Resilience in Green Microalgae.

    Science.gov (United States)

    Guihéneuf, Freddy; Khan, Asif; Tran, Lam-Son P

    2016-01-01

    As we march into the 21st century, the prevailing scenario of depleting energy resources, global warming and ever increasing issues of human health and food security will quadruple. In this context, genetic and metabolic engineering of green microalgae complete the quest toward a continuum of environmentally clean fuel and food production. Evolutionarily related, but unlike land plants, microalgae need nominal land or water, and are best described as unicellular autotrophs using light energy to fix atmospheric carbon dioxide (CO2) into algal biomass, mitigating fossil CO2 pollution in the process. Remarkably, a feature innate to most microalgae is synthesis and accumulation of lipids (60-65% of dry weight), carbohydrates and secondary metabolites like pigments and vitamins, especially when grown under abiotic stress conditions. Particularly fruitful, such an application of abiotic stress factors such as nitrogen starvation, salinity, heat shock, etc., can be used in a biorefinery concept for production of multiple valuable products. The focus of this mini-review underlies metabolic reorientation practices and tolerance mechanisms as applied to green microalgae under specific stress stimuli for a sustainable pollution-free future. Moreover, we entail current progress on genetic engineering as a promising tool to grasp adaptive processes for improving strains with potential biotechnological interests. PMID:27066043

  19. Response of Marine Microalgae, Heterotrophic Bacteria and Their Relationship to Enhanced UV-B Radiation

    Institute of Scientific and Technical Information of China (English)

    ZHOU Wenli; TANG Xuexi; XIAO Hui; WANG You; WANG Renjun

    2009-01-01

    Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and pho-tosynthesis rate; this rachation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a nucroalgal ecological dynamic model at population and community levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae communities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microal-gae and heterotrophic bacteria and the interaction between them.

  20. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura; Dr. Miguel Olaizola; Dr. Stephen M. Masutani

    2002-01-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report is the summary first year report covering the reporting period 1 October 2000 to 30 September 2001 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on the component optimization work. Aquasearch continued their effort on selection of microalgae suitable for CO{sub 2} sequestration. University of Hawaii initiated effort on system optimization of the CO{sub 2} sequestration system.

  1. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura; Dr. Miguel Olaizola; Dr. Steven M. Masutani

    2001-08-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 April to 30 June 2001 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on the component optimization work. Aquasearch continued their effort on selection of microalgae suitable for CO{sub 2} sequestration. University of Hawaii initiated effort on system optimization of the CO{sub 2} sequestration system.

  2. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura; Dr. Miguel Olaizola; Dr. Stephen M. Masutani

    2002-07-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 April to 30 June 2001 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on the component optimization work. Aquasearch continued their effort on selection of microalgae suitable for CO{sub 2} sequestration. University of Hawaii initiated effort on system optimization of the CO{sub 2} sequestration system.

  3. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura; Dr. C.L. Senior

    2001-05-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 January to 31 March 2001 in which Aquasearch tested 24 different species of microalgae for growth at three different temperatures. Eleven species were analyzed for the presence of high-value pigments. Most of the algae analyzed were good sources of industrially valuable pigments. Analysis of the methods for introducing and dissolving CO{sub 2} in the commercial bioreactor was begun this quarter.

  4. Numerical investigation of a bubble-column photo-bioreactor design for biodiesel production from microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Seo, I.H.; Lee, I.B.; Hwang, H.S.; Hong, S.W.; Bitog, J.P.; Kwon, K.S.; Choi, J.S.; Song, S.H. [Seoul National Univ., Seoul (Korea, Democratic People' s Republic of). Dept. of Rural Systems Engineering and Research Inst. for Agriculture and Life Sciences

    2010-07-01

    Biodiesel made from vegetable oil is among the most desirable of renewable energy sources because it can be a substitute for diesel oil. However, biodiesel from soybean or corn can be confronted with a food crisis. Microalgae is a new biodiesel source which contains high oil lipids with a high growth rate, and which also offers value-added products from the residue, such as cosmetics, health functional food or pharmaceuticals. Microalgae are best cultivated in photo-bioreactors (PBRs) where light, nutrients, carbon dioxide and temperature can be controlled. Despite the current availability of PBRs, only a few can be practically used for mass production. Computational fluid dynamics (CFD) was used in this study to design an optimum bubble-column PBR for mass production of microalgae. Multi-phase models including bubble movement, meshes and time step independent tests were considered to develop the 3-dimensional CFD model. Particle Image Velocimetry (PIV) tests were used to enhance and validate the model. Different types of PBRs were simulated and compared quantitatively with the microalgae's growth model.

  5. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    International Nuclear Information System (INIS)

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO(sub 2) from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 October to 31 December 2001 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on the component optimization work. Aquasearch continued their effort on selection of microalgae suitable for CO(sub 2) sequestration. University of Hawaii initiated effort on system optimization of the CO(sub 2) sequestration system

  6. Effect of heavy metals on the growth of the tropical microalgae Tetrasermis chuii (Prasinophyceae)

    International Nuclear Information System (INIS)

    This paper determined the toxic effect of four metals, cadmium (Cd), copper (Cu), mercury (Hg) and lead (Pb), on the tropical microalgae Tetrasermis Chuii (Butcher, 1959). We exposed 50 ml of cultivated microalgae (f/2 Guillard) in the exponential growth phase, with three replicates, to concentrations of 0 (control), 0.1, 1.0, 5.0, 10.0 and 20.0 mg.l-1 with each metal for 96 hr. We evaluated the lethal effect daily, through the cellular count. In the control treatment (not exposed to any metal) we observed and increase in cellular density. In all treatments exposed to metals, we observed a decrease in cellular density, which accelerated in 48 h, after which it became less pronounced. There were exceptions with low concentrations of Cd and Cu at 24 h, as there was no significant decrease, probably due to their use as micro nutrients at these low concentrations. The metal that caused the most lethal effect was Pb, which killed 50% of the microalgae population at a concentration of 0.40 mg.l-1. This concentration was 3 times lower than that of mercury and 13 times lower than those of cadmium and copper. The microalgae Tetrasermis chuii is recommended as a model species to estimate the toxic effects of xenobiotics on tropical seawater environments. (Author)

  7. The analysis on energy and environmental impacts of microalgae-based fuel methanol in China

    International Nuclear Information System (INIS)

    The whole life of methanol fuel, produced by microalgae biomass which is a kind of renewable energy, is evaluated by using a method of life cycle assessment (LCA). LCA has been used to identify and quantify the environment emissions and energy efficiency of the system throughout the whole life cycle, including microalgae cultivation, methanol conversion, transport, and end-use. Energy efficiency, defined as the ratio of the energy of methanol produced to the total required energy, is 1.24, the results indicate that it is plausible as an energy producing process. The environmental impact loading of microalgae-based fuel methanol is 0.187mPET2000 in contrast to 0.828mPET2000 for gasoline. The effect of photochemical ozone formation is the highest of all the calculated categorization impacts of the two fuels. Utilization of microalgae an raw material of producing methanol fuel is beneficial to both production of renewable fuels and improvement of the ecological environment. This Fuel methanol is friendly to the environment, which should take an important role in automobile industry development and gasoline fuel substitute

  8. Changes in photosynthetic activity of microalgae under the influence of electromagnetic radiation

    International Nuclear Information System (INIS)

    We studied the effect of UHF radiation on photosynthetic activity in pro- and eukaryotic microalgae. A rise of photosynthetic activity is shown to occur, this rise being accompanied by increase of pigment content in the cells and depending on both exposure time and culture age

  9. Green energy from microalgae: Usage of algae biomass for anaerobic digestion

    International Nuclear Information System (INIS)

    The microalgae biomass can be used for various types of biofuels, including biodiesel and biogas. The aim of this study is to investigate the possibilities of microalgae Scenedesmus sp. and Chlorella sp. (widespread in freshwater Lithuanian lakes) usage for biogas production. Microalgae were cultivated under mixotrophic conditions (growth medium BG11 containing technical glycerol). In order to determine biogas yield and quality dependence on feedstock preparation, the analyses of biogas production have been performed with algae biomass prepared i n different ways: wet centrifuged; wet centrifuged, frozen and defrost; dry not de-oiled and dry de-oiled. The highest biogas yield in both cases (Scenedesmus sp. – 646 ml/gDM and Chlorella sp. – 652 ml/gDM) was obtained from centrifuged, frozen and defrost biomass. Biogas yield was app. 1.46 times higher comparing to yield of biogas produced from wastewater sludge. Our results showed that different types of biomass preparation have no significant influence on quality of biogas. Key words: microalgae, biomass, biogas production, biogas quality

  10. A novel self-adaptive microalgae photobioreactor using anion exchange membranes for continuous supply of nutrients.

    Science.gov (United States)

    Fu, Qian; Chang, Hai-Xing; Huang, Yun; Liao, Qiang; Zhu, Xun; Xia, Ao; Sun, Ya-Hui

    2016-08-01

    A novel self-adaptive microalgae photobioreactor using anion exchange membranes (AEM-PBR) for continuous supply of nutrients was proposed to improve microalgae biomass production. The introduction of anion exchange membranes to the PBR can realize continuous supply of nutrients at desired rates, which is beneficial to the growth of microalgae. The results showed that the maximum biomass concentration obtained in the AEM-PBR under continuous supply of nitrogen at an average rate of 19.0mgN/L/d was 2.98g/L, which was 129.2% higher than that (1.30g/L) in a PBR with all the nitrogen supplied in batch at initial. In addition, the feeding rates of nitrogen and phosphorus were optimized in the AEM-PBR to maximize biomass production. The maximum biomass concentration of 4.38g/L was obtained under synergistic regulation of nitrogen and phosphorus feeding rates at 19.0mgN/L/d and 4.2mgP/L/d. The AEM-PBR demonstrates a promising approach for high-density cultivation of microalgae. PMID:27187567

  11. Stress-induced neutral lipid biosynthesis in microalgae - Molecular, cellular and physiological insights.

    Science.gov (United States)

    Zienkiewicz, Krzysztof; Du, Zhi-Yan; Ma, Wei; Vollheyde, Katharina; Benning, Christoph

    2016-09-01

    Photosynthetic microalgae have promise as biofuel feedstock. Under certain conditions, they produce substantial amounts of neutral lipids, mainly in the form of triacylglycerols (TAGs), which can be converted to fuels. Much of our current knowledge on the genetic and molecular basis of algal neutral lipid metabolism derives mainly from studies of plants, i.e. seed tissues, and to a lesser extent from direct studies of algal lipid metabolism. Thus, the knowledge of TAG synthesis and the cellular trafficking of TAG precursors in algal cells is to a large extent based on genome predictions, and most aspects of TAG metabolism have yet to be experimentally verified. The biofuel prospects of microalgae have raised the interest in mechanistic studies of algal TAG biosynthesis in recent years and resulted in an increasing number of publications on lipid metabolism in microalgae. In this review we summarize the current findings on genetic, molecular and physiological studies of TAG accumulation in microalgae. Special emphasis is on the functional analysis of key genes involved in TAG synthesis, molecular mechanisms of regulation of TAG biosynthesis, as well as on possible mechanisms of lipid droplet formation in microalgal cells. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner. PMID:26883557

  12. Bio-gasification of post transesterified microalgae residues: A route to improving overall process renewabilities

    DEFF Research Database (Denmark)

    Ehimen, Ehiazesebhor Augustine

    Using results from experiments and process modelling tools, a renewability assessment was carried out for the use of the conventional and in-situ transesterification processes for a large scale microalgae biodiesel production. In a present day scenario, all the transesterification processes were...

  13. Strategies for Lipid Production Improvement in Microalgae as a Biodiesel Feedstock

    Science.gov (United States)

    Li, Z. H.; Hiltunen, E.

    2016-01-01

    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. PMID:27725942

  14. Proteomic Alterations of Antarctic Ice Microalga Chlamydomonas sp. Under Low-Temperature Stress

    Institute of Scientific and Technical Information of China (English)

    Guang-Feng Kan; Jin-Lai Miao; Cui-Juan Shi; Guang-You Li

    2006-01-01

    Antarctic ice microalga can survive and thrive in cold channels or pores in the Antarctic ice layer. In order to understand the adaptive mechanisms to low temperature, in the present study we compared two-dimensional polyacrylamide gel electrophoresis (2-DE) profiles of normal and low temperature-stressed Antarctic ice microalga Chlamydomonas sp. cells. In addition, new protein spots induced by low temperature were identified with peptide mass fingerprinting based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and database searching. Well-resolved and reproducible 2-DE patterns of both normal and low temperature-stressed cells were acquired. A total of 626 spots was detected in control cells and 652 spots were detected in the corresponding low temperature-stressed cells. A total of 598 spots was matched between normal and stressed cells. Two newly synthesized proteins (a and b) in low temperature-stressed cells were characterized. Protein spot A (53 kDa, pI 6.0) was similar to isopropylmalate/homocitrate/citramalate synthases, which act in the transport and metabolism of amino acids. Protein spot b (25 kDa, pI 8.0) was related to glutathione S-transferase, which functions as a scavenger of active oxygen, free radicals, and noxious metabolites. The present study is valuable for the application of ice microalgae, establishing an ice microalga Chlamydomonas sp. proteome database, and screening molecular biomarkers for further studies.

  15. Toxicity of atrazine and its bioaccumulation and biodegradation in a green microalga, Chlamydomonas mexicana.

    Science.gov (United States)

    Kabra, Akhil N; Ji, Min-Kyu; Choi, Jaewon; Kim, Jung Rae; Govindwar, Sanjay P; Jeon, Byong-Hun

    2014-11-01

    This study evaluated the toxicity of herbicide atrazine, along with its bioaccumulation and biodegradation in the green microalga Chlamydomonas mexicana. At low concentration (10 μg L(-1)), atrazine had no profound effect on the microalga, while higher concentrations (25, 50, and 100 μg L(-1)) imposed toxicity, leading to inhibition of cell growth and chlorophyll a accumulation by 22 %, 33 %, and 36 %, and 13 %, 24 %, and 27 %, respectively. Atrazine 96-h EC50 for C. mexicana was estimated to be 33 μg L(-1). Microalga showed a capability to accumulate atrazine in the cell and to biodegrade the cell-accumulated atrazine resulting in 14-36 % atrazine degradation at 10-100 μg L(-1). Increasing atrazine concentration decreased the total fatty acids (from 102 to 75 mg g(-1)) and increased the unsaturated fatty acid content in the microalga. Carbohydrate content increased gradually with the increase in atrazine concentration up to 15 %. This study shows that C. mexicana has the capability to degrade atrazine and can be employed for the remediation of atrazine-contaminated streams.

  16. Recent Developments on the Production of Transportation Fuels via Catalytic Conversion of Microalgae: Experiments and Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Fan; Wang, Ping; Duan, Yuhua; Link, Dirk; Morreale, Bryan

    2012-08-02

    Due to continuing high demand, depletion of non-renewable resources and increasing concerns about climate change, the use of fossil fuel-derived transportation fuels faces relentless challenges both from a world markets and an environmental perspective. The production of renewable transportation fuel from microalgae continues to attract much attention because of its potential for fast growth rates, high oil content, ability to grow in unconventional scenarios, and inherent carbon neutrality. Moreover, the use of microalgae would minimize “food versus fuel” concerns associated with several biomass strategies, as microalgae do not compete with food crops in the food chain. This paper reviews the progress of recent research on the production of transportation fuels via homogeneous and heterogeneous catalytic conversions of microalgae. This review also describes the development of tools that may allow for a more fundamental understanding of catalyst selection and conversion processes using computational modelling. The catalytic conversion reaction pathways that have been investigated are fully discussed based on both experimental and theoretical approaches. Finally, this work makes several projections for the potential of various thermocatalytic pathways to produce alternative transportation fuels from algae, and identifies key areas where the authors feel that computational modelling should be directed to elucidate key information to optimize the process.

  17. RECOVERY AND SEQUESTRATION OF CO2 FROM STATIONARY COMBUSTION SYSTEMS BY PHOTOSYNTHESIS OF MICROALGAE

    Energy Technology Data Exchange (ETDEWEB)

    Dr. T. Nakamura; Dr. Miguel Olaizola; Dr. Stephen M. Masutani

    2002-03-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 October to 31 December 2001 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work conducted during the previous reporting period, PSI initiated work on the component optimization work. Aquasearch continued their effort on selection of microalgae suitable for CO{sub 2} sequestration. University of Hawaii initiated effort on system optimization of the CO{sub 2} sequestration system.

  18. Development of a Two-Stage Microalgae Dewatering Process – A Life Cycle Assessment Approach

    Science.gov (United States)

    Soomro, Rizwan R.; Zeng, Xianhai; Lu, Yinghua; Lin, Lu; Danquah, Michael K.

    2016-01-01

    Even though microalgal biomass is leading the third generation biofuel research, significant effort is required to establish an economically viable commercial-scale microalgal biofuel production system. Whilst a significant amount of work has been reported on large-scale cultivation of microalgae using photo-bioreactors and pond systems, research focus on establishing high performance downstream dewatering operations for large-scale processing under optimal economy is limited. The enormous amount of energy and associated cost required for dewatering large-volume microalgal cultures has been the primary hindrance to the development of the needed biomass quantity for industrial-scale microalgal biofuels production. The extremely dilute nature of large-volume microalgal suspension and the small size of microalgae cells in suspension create a significant processing cost during dewatering and this has raised major concerns towards the economic success of commercial-scale microalgal biofuel production as an alternative to conventional petroleum fuels. This article reports an effective framework to assess the performance of different dewatering technologies as the basis to establish an effective two-stage dewatering system. Bioflocculation coupled with tangential flow filtration (TFF) emerged a promising technique with total energy input of 0.041 kWh, 0.05 kg CO2 emissions and a cost of $ 0.0043 for producing 1 kg of microalgae biomass. A streamlined process for operational analysis of two-stage microalgae dewatering technique, encompassing energy input, carbon dioxide emission, and process cost, is presented. PMID:26904075

  19. Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus CNW-N.

    Science.gov (United States)

    Chen, Wei-Hsin; Wu, Zih-Ying; Chang, Jo-Shu

    2014-03-01

    Isothermal and non-isothermal torrefaction characteristics and kinetics of microalga Scenedesmus obliquus (S. obliquus) CNW-N are studied using thermogravimetric analysis. The pyrolysis of S. obliquus CNW-N with increasing temperature is characterized by four-stage decomposition. Depending on the torrefaction temperature, light, mild, and severe torrefaction from the weight loss and the maximum decomposition rate of the microalga can be classified. Under the same average temperature and torrefaction duration, non-isothermal torrefaction gives more severe pretreatment than the isothermal one. Increasing the heating rate of non-isothermal torrefaction also intensifies the pretreatment severity. Therefore, microalgae can be torrefied via non-isothermal torrefaction in a shorter time under the same pretreatment extent. The atomic H/C ratio in the microalga decreases with increasing torrefaction severity, whereas the atomic O/C ratio rises. The analysis suggests that the activation energy of isothermal torrefaction is 57.52×10(3)Jmol(-1), while it is between 40.14×10(3) and 88.41×10(3)Jmol(-1) for non-isothermal torrefaction.

  20. Recovery and Sequestration of CO2 from Stationary Combustion Systems by Photosynthesis of Microalgae

    Energy Technology Data Exchange (ETDEWEB)

    T. Nakamura; C.L. Senior

    2005-04-01

    Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 October 2000 to 31 March 2005 in which PSI, Aquasearch and University of Hawaii conducted their tasks. This report discusses results of the work pertaining to five tasks: Task 1--Supply of CO2 from Power Plant Flue Gas to Photobioreactor; Task 2--Selection of Microalgae; Task 3--Optimization and Demonstration of Industrial Scale Photobioreactor; Task 4--Carbon Sequestration System Design; and Task 5--Economic Analysis. Based on the work conducted in each task summary conclusion is presented.