47 research outputs found
Producción de Compuestos Orgánicos de Valor Comercial a partir de la Biomasa Microalgal de Scenedesmus Dimorphus
Las microalgas son una prometedora fuente de compuestos orgánicos de valor comercial, ya que su cultivo se puede integrar con el aprovechamiento de corrientes residuales industriales, potenciando tanto la sustentabilidad como la
rentabilidad de los procesos productivos.En este trabajo se estudió el rendimiento de extracciones secuenciales, con solventes n- hexano, etanol y acetona, de la biomasa de Scenedesmus dimorphus, cultivada en condiciones control y de estrés nutricional. El contenido lipídico fue de 162,6 mg/g y 265,8 mg/g respectivamente. Se observa que, sometido a falta de nutrientes, el cultivo produce una acumulación no solamente de lípidos (aumento de 344% p/p), sino de carbohidratos, astaxantina y sus ésteres.
Los resultados muestran que a partir de cultivos de S. dimorphus es posible obtener distintos metabolitos orgánicos de interés, con métodos y solventes de extendido uso industrial, que no son los que frecuentemente se encuentran en la bibliografía de estudios microalgales
The culture of coccolithophorid algae for carbon dioxide bioremediation
The culture of coccolithophorid algae is an attractive option for sequestration or recycling of CO2 as they can fix carbon by photosynthesis as well as in calcium carbonate scales known as coccoliths. They also produce high amounts of lipids which have a potential application as a renewable fuel.
Five species of coccolithophorids (Pleurochrysis carterae, CCMP647, Pleurochrysis sp. CCMP1211, Gephyrocapsa oceanica CS-335/2, Emiliania huxleyi CCMP371, and Emiliania huxleyi CS-369) were screened for their ability to grow at high temperature. All species grew up to 28oC except E. huxleyi CS-369. However, Pleurochrysis sp. CCMP 1211 which was found to clump and can therefore not be recommended for large-scale cultivation. The salinity tolerance of these species was also examined.
Growth of P. carterae, G. oceanica, and E. huxleyi in laboratory scale closed photobioreactors (plate, carboy, airlift, and tubular photobioreactors) showed the plate photobioreactor to be the best closed cultivation system. The highest productivities were achieved by P. carterae in the plate photobioreactor and were 0.54 g.L-1.d-1, 0.12 g.L-1.d-1, 0.06 g.L-1.d-1 for total dry weight, lipid and CaCO3 respectively. The growth of P. carterae and E. huxleyi was also examined in an outdoor raceway pond. The E. huxleyi culture was easily contaminated resulting in the loss of the culture in less than three weeks, but P. carterae grew well over a period of 13 months. The overall total dry weight productivity of P. carterae was 0.19 g.L-1.d-1 with lipid and CaCO3 contents of up to 33% and 10% of dry weight respectively. There was little protozoan and bacterial contamination. Medium pH increased to pH 11 during the day and was found to be a reliable variable for maintaining the health of the culture. A maximum pH achieved during the day of less than pH 8.5 indicated the imminent collapse of the culture. Heavy rain and low temperature were the main reasons for culture loss in mid winter, whereas high temperature during summer favoured P. carterae growth. A comparison of the growth of P. carterae and Dunaliella salina MUR8 in the raceway ponds showed no significant differences between these two species with regard to areal total dry weight productivity and lipid content.
The effects of several limiting factors were also examined. A reduction in medium pH resulting from CO2 addition inhibited the growth of E. huxleyi in the plate photobioreactor, whereas P. carterae growth and productivities increased in the pH range of pH 7.7 to 8.0 in the plate photobioreactor and pH 9.1 to 9.6 in the outdoor raceway pond. The best operational pond depth for outdoor raceway culture of P. carterae was between 16 cm and 21 cm. Early morning temperatures, especially during the winter, highly affected the growth of P. carterae in the raceway pond, whereas artificially increasing the medium temperature improved the health of the culture but resulted in little increase in productivity. Photosynthesis of P. carterae was found to be highly inhibited by high oxygen concentration in the medium irrespective of temperature or irradiance.
An economic model of P. carterae in a 63 ha raceway plant resulted in a cost for the biomass of between 7.35 Aus.Kg-1 depending on the harvesting method used
Análisis preliminar del comportamiento de Azospirillum brasilense como promotora del crecimiento de Scenedesmus dimorphus para el tratamiento de efluentes combinados
Se realizó la primera prueba del uso de la bacteria Azospirillum brasilense como promotora del crecimiento de Scenedesmus dimorphus. Se emplearon como medio de cultivo efluentes líquidos provenientes de dos orígenes: el lixiviado de una planta de tratamiento de residuos sólidos urbanos, rico en metales (Mg, Ca, Zn) y el residuo líquido de la lechería Pampa Gringa, rico en compuestos nitrogenados y fosforados, ambos efluentes de la localidad de Lincoln, Provincia de Buenos Aires, Argentina. Se probó el comportamiento del alga en los efluentes solos (100% v/v) y en concentraciones de los mismos combinados (50%-50% y 75%-25% v/v de sendos efluentes). El cultivo se desarrolló en bioreactores de 500mL agitados sin aireación, con períodos de luz/oscuridad de 16h:8h, primero como proceso batch y luego semicontinuo. Se evaluó el crecimiento de la microalga sola y su comportamiento con la promoción de la bacteria en las mismas concentraciones de efluentes. La inoculación inicial de Azospirillum brasilense fue de 109cél/mL. La incorporación de la bacteria en todos los medios de cultivo mostró una mejora en productividad de biomasa de S. dimorphus, reflejada en la tasa de crecimiento del alga, obtenida por recuento celular.
Los resultados preliminares indicarían que la formación de estos consorcios alga-bacteria, maximizarían
tanto la generación de biomasa para la posterior extracción de metabolitos de interés comercial, como el
tratamiento de efluentes con distinto origen y composición, lo que permitiría un manejo sustentable de los
residuos producto de la actividad humana y un incremento en la rentabilidad de los cultivos microalgales.
Posteriores estudios permitirían optimizar los consorcios en mayores volúmenes para ser llevados a su uso a escala comercial.Fil: Cuello, María. Universidad Tecnológica Nacional. Facultad Regional Resistencia. Centro de Investigación en Química Orgánica - Biológica; ArgentinaFil: Chamorro, Ester. Universidad Tecnológica Nacional. Facultad Regional Resistencia. Centro de Investigación en Química Orgánica - Biológica; ArgentinaFil: Moheimani, Navid. Universidad Tecnológica Nacional. Facultad Regional Resistencia. Centro de Investigación en Química Orgánica - Biológica; ArgentinaPeer Reviewe
Techno-economic modelling of high-value metabolites and secondary products from microalgae cultivated in closed photobioreactors with supplementary lighting
The purpose of this study is to develop an initial computational model to evaluate the techno-economic viability of high-value and secondary resources from microalgae. The isolation of high-value metabolites is the driving product to improve the overall economics. This approach will allow marketing secondary compounds at more competitive rates for applications such as biofuel, biomaterials, food or animal feed supplements. In this assessment, we consider cultivations in flat-panel, airlift and tubular closed photobioreactor [PBR] systems to avoid possible contamination and limit environmental exposures. The facilities are also equipped with supplementary LED lightings and temperature control to improve productivity. Based on the methodology described in this work, we evaluate the techno-economic viability of the suggested systems. A probable productivity range is selected based on the logistic growth with a recovery rate between 60% and 80%. The sensitivity analysis shows that the ratio of high-value metabolites is the most crucial factor determining the economics. Microalgae prices and productivities gain more importance at higher ratios. The sensitivity analyses indicate a low-level impact of productivity and cultivation costs on high priced metabolites.This publication was made possible by the QNRF-MME grant # [MME01-0924-190063] from the Qatar National Research Fund (a member of Qatar Foundation) and the Ministry of Municipality and Environment, Qatar. The findings herein reflect the work, and are solely the responsability of the authors
Producción de Compuestos Orgánicos de Valor Comercial a partir de la Biomasa Microalgal de Scenedesmus Dimorphus
Microalgae are a promising source of commercial organic compounds since its culturing could be integrated to existing industrial processes, promoting joint goals of sustainability and profitability. Yield of serial extractions with n-hexane, ethanol and acetone of Scenedesmus dimorphus was studied. Samples of algal biomass cultured under normal and stressed conditions were taken and lipid content obtained was 162,6 mg/g and 265,8 mg/g, respectively. It was also observed that culture deprived from nutrients not only accumulates lipids (344% w/w increase) but also carbohydrates, astaxanthin and its esters.Results show that it is possible to obtain different organic products from S. dimorphus cultures, with solvents and techniques commonly used in the industrial field but rarely found in microalgae current bibliography.Las microalgas son una prometedora fuente de compuestos orgánicos de valor comercial, ya que su cultivo se puede integrar con el aprovechamiento de corrientes residuales industriales, potenciando tanto la sustentabilidad como la rentabilidad de los procesos productivos.En este trabajo se estudió el rendimiento de extracciones secuenciales, con solventes n- hexano, etanol y acetona, de la biomasa de Scenedesmus dimorphus, cultivada en condiciones control y de estrés nutricional. El contenido lipídico fue de 162,6 mg/g y 265,8 mg/g respectivamente. Se observa que, sometido a falta de nutrientes, el cultivo produce una acumulación no solamente de lípidos (aumento de 344% p/p), sino de carbohidratos, astaxantina y sus ésteres.Los resultados muestran que a partir de cultivos de S. dimorphus es posible obtener distintos metabolitos orgánicos de interés, con métodos y solventes de extendido uso industrial, que no son los que frecuentemente se encuentran en la bibliografía de estudios microalgales
Biomass production of marine microalga Tetraselmis suecica using biogas and wastewater as nutrients
Anaerobic digestion is a suitable method for treating organic wastes and generating biogas. This biogas contains significant amount of CO2 and some other contaminants. The coupling of wastewater treatment with biogas purification using saline microalgae could effectively upgrade biogas (through photosynthetic CO2 fixation) and concurrently remove nutrients from the effluent, while producing valuable algal biomass. In this context, Tetraselmis suecica biomass production with the use of an impurity (CO2) in biogas to supply carbon, and nutrients (nitrogen and phosphorus) from anaerobically-digested piggery effluent (ADPE) was investigated at four operating pH set points (6.5, 7.5, 8.5 and 9.5). Results showed that pH 7.5 produced the optimum conditions for T. suecica growth and biogas-based CO2 removal, with the maximum biomass (59.8 mg L−1 d−1), lipid (25 mg L−1 d−1) and carbohydrate (6.5 mg L-1 d-1) productivities. Under this condition, CO2, total nitrogen and phosphorus removal efficiencies were 94.7%, 96% and 72%, respectively. Furthermore, the results showed no inhibitory effect of dissolved CH4 on the growth of T. suecica at pH 7.5, suggesting the technical feasibility of harnessing marine T. suecica for simultaneous nutrients removal from wastewaters, biogas upgrading, and production of energy-rich algal biomass. This process clearly harnesses anaerobically-digested piggery effluent not only as an asset but also uses an impurity (CO2) in biogas to produce valuable algal biomass
Marine microbial bioprospecting: Exploitation of marine biodiversity towards biotechnological applications—a review
The increase in the human population causes an increase in the demand for nutritional supplies and energy resources. Thus, the novel, natural, and renewable resources became of great interest. Here comes the optimistic role of bioprospecting as a promising tool to isolate novel and interesting molecules and microorganisms from the marine environment as alternatives to the existing resources. Bioprospecting of marine metabolites and microorganisms with high biotechnological potentials has gained wide interest due to the variability and richness of the marine environment. Indeed, the existence of extreme conditions that increases the adaptability of marine organisms, especially planktons, allow the presence of interesting biological species that are able to produce novel compounds with multiple health benefits and high economical value. This review aims to provide a comprehensive overview of marine microbial bioprospecting as a growing field of interest. It emphasizes functional bioprospecting that facilitates the discovery of interesting metabolites. Marine bioprospecting was also discussed from a legal aspect for the first time, focusing on the shortcomings of international law. We also summarized the challenges facing bioprospecting in the marine environment including economic feasibility issues.This report was made possible by the NPRP award (NPRP11S-0110-180248) from the Qatar National Research Fund (a member of The Qatar Foundation). The statements made herein are solely the responsibility of the authors. Special thanks go to the Centre for Sustainable Development for the support