RESUMEN
It is proposed that two little-known species of Castniidae which have been traditionally assigned to the genus Athis Hubner belong to other genera; in addition, both have been found to have better-known junior synonyms. The statuses of the following taxa have been revised in this work: Castnia amalthaea H. Druce comb. rest., Castnia lecerfi Dalla Torre syn. nov., Castnia minerva R. Krüger syn. nov., Insigniocastnia bogota (Strand) comb. nov. and Insigniocastnia taisae J. Y. Miller syn. nov. A revision is presented for the genus Insigniocastnia J. Y. Miller. The female of I. bogota (Strand) has been unknown since its original description; it is herein described and illustrated for the first time.
Asunto(s)
Lepidópteros , Animales , FemeninoRESUMEN
Microalgae-based biodiesel has several benefits over other resources such as less land use, potential cultivation in non-fertile locations, faster growth and especially a high lipid-to-biodiesel yield. Nevertheless, the environmental and economic behavior for high scale production depends on several variables that must be addressed in the scale-up procedure. In this sense, rigorous modeling and multicriteria evaluation are performed in order to achieve optimal topology for third generation biodiesel production. Different scenarios and the most promising technologies tested at pilot scale are assessed. Besides, the sensitivity analysis allows the detection of key operating variables and assumptions that have a direct effect on the lipid content. The deviation of these variables may lead to an erroneous estimation of the scale-up performance of the technology reviewed in the microalgae-based biodiesel process. The modeling and evaluation of different scenarios of the harvesting, oil extraction and transesterification help to identify greener and cheaper alternatives.
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Biocombustibles , Microalgas/metabolismo , BiomasaRESUMEN
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 selected strain, medium, harvesting methods, etc., sorely affects the ash content in the dry biomass which have a direct effect in the lipid content. Moreover, the suitable lipids for biodiesel production, some of the neutral/saponifiable, are only a fraction of the total ones (around 30% dry base biomass in the best case). The present work uses computational tools for the modeling of different scenarios of the harvesting, oil extraction and transesterification. This rigorous modeling approach detects process bottlenecks that could have led to an overestimation of the potentiality of the microalgae lipids as a resource for the biodiesel production.
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Biocombustibles/economía , Biocombustibles/microbiología , Biotecnología/economía , Biotecnología/métodos , Microalgas/metabolismo , Biomasa , Costos y Análisis de Costo , Esterificación , Microalgas/crecimiento & desarrolloRESUMEN
Microalgae can grow rapidly and capture CO2 from the atmosphere to convert it into complex organic molecules such as lipids (biodiesel feedstock). High scale economically feasible microalgae based oil depends on optimizing the entire process production. This process can be divided in three very different but directly related steps (production, concentration, lipid extraction and transesterification). The aim of this study is to identify the best method of lipid extraction to undergo the potentiality of some microalgal biomass obtained from two different harvesting paths. The first path used all physicals concentration steps, and the second path was a combination of chemical and physical concentration steps. Three microalgae species were tested: Phaeodactylum tricornutum, Nannochloropsis gaditana, and Chaetoceros calcitrans One step lipid extraction-transesterification reached the same fatty acid methyl ester yield as the Bligh and Dyer and soxhlet extraction with n-hexane methods with the corresponding time, cost and solvent saving.
Asunto(s)
Biocombustibles/microbiología , Biomasa , Biotecnología/métodos , Lípidos/aislamiento & purificación , Microalgas/metabolismo , Ácido Eicosapentaenoico/metabolismo , Ésteres/metabolismo , Liofilización , Microalgas/crecimiento & desarrollo , Fotobiorreactores/microbiologíaRESUMEN
Microalgae are microorganisms that can fix CO(2) by using the energy from the sun and transforming it into organic molecules such as lipids (i.e. feedstock for biodiesel production). Microfiltration is a promising method to be considered in the harvesting step. In this study, two antifouling methods were tested in order to minimize permeability decrease over time, at low trans-membrane pressure filtration. Preliminary experiments were performed to find optimum conditions of transmembrane pressure, rotational speed and membrane pore size. Pilot experiments were carried out in the optimal conditions using microalgae obtained from the culture step and from a previous concentration process based on sedimentation. Fouling was significantly minimized, and the permeability plateau increased up to 600 L/h/m(2)/bar. Three microalgae species were tested: Phaeodactylum tricornutum (Pht), Nannochloropsis gaditana (Nng) and Chaetoceros calcitrans (Chc). An economic assessment was also performed, which demonstrated that dynamic filtration is economically more efficient than tangential cross-flow filtration.