Papers by Wallyson Ribeiro Dos Santos
Waste and Biomass Valorization, 2021
Purpose Microalgal biomass composition can be modulated by changing the type of bioreactor and cu... more Purpose Microalgal biomass composition can be modulated by changing the type of bioreactor and cultivation conditions. Besides, these microorganisms can produce valuable biomass components from unconventional culture media, including effluents and wastes. Our objective was to evaluate the production and composition of biomass in an airlift bioreactor operated in a semi-continuous mode to cultivate the microalgae Chlorella minutissima in a landfill leachate-based medium. Methods Chlorella minutissima was cultivated in an airlift bioreactor operated in semi-continuous mode, applying a Taguchi L9 orthogonal arrangement and analyzing the effects of factors landfill leachate concentration (LC), percentage flux of CO 2 added to the gas stream (GP), aeration flow in the reactor (AF), and feed flow (FR), on the cellular composition of biomass. Results The microalgae produced high protein levels, reaching a maximum content of 69.60% (LC: 10%, GP: null, AF: 0.30 vvm and FR: 0.9 µ max). The highest contents of lipid and carbohydrate were 17.4% (LC: 15%, GP: null, AF: 0.45 vvm and FR: 0.7 µ max vvm) and 11.6% (LC: 10%, GP: 15%, AF: 0.15 vvm and FR: 0.7 µ max). Statistical analysis showed LC was the most influential factor. GP did not show significance for any response, while the variables AF and FR showed significance in the productivity of proteins. Conclusion The use of unconventional cultivation media in airlift bioreactor operated in semi-continuous mode was shown as a system with potential to be used to valorize leachate by producing valuable biomass, allowing to obtain different cell composition by varying the process conditions.
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Análisis físicoquímico de biodiesel obtenido por mezclas de aceite de castor y aceite de freír , 2019
La producción de combustibles renovables ha tenido un gran impulso en los últimos años. Una alter... more La producción de combustibles renovables ha tenido un gran impulso en los últimos años. Una alternativa es la producción de aceites vegetales con la capacidad de reemplazar todo o parte del diesel derivado del petróleo. El objetivo de este trabajo fue producir biodiesel a partir de mezclas de aceite de ricino virgen (VCO) y aceite de fritura (WFO) a partir de ruta etílica y catálisis alcalina y estudiar las propiedades físicas y químicas de los mismos. El biodiesel se obtuvo a partir de 5 diferentes materias primas: VCO (B1), WFO (B2) y tres mezclas diferentes (B3: 50% VCO; B4: 25% VCO; B5: 75% VCO). Las materias primas fueron evaluadas por el nivel de acidez, ácidos grasos libres, índice de saponificación y densidad. Para el biodiesel se determinó el índice de yodo, cetano, glicerina, ausencia de triglicéridos y reología. De acuerdo con los resultados, todas las muestras se encontraron dentro del estándar especificado para índice de yodo y densidad, pero el biodiesel de B1 presentó viscosidad y número de cetano no permitidos en la legislación. A pesar de que los resultados de B4 y B5 se ubicaron dentro de la legislación para biodiesel, B4 sería una mejor alternativa debido a una mayor cantidad de WFO.
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Análise das variáveis de processo na composição celular e nos parâmetros reológicos da Chlorella minutissima, cultivada em reator Air-Lift, para a produção de biocombustíveis, 2019
The present work evaluated the cellular composition and the rheological behavior of
suspensions o... more The present work evaluated the cellular composition and the rheological behavior of
suspensions of Chlorella minutissima cultivated in slurry (landfill leachate) in reactors
operated in batch and semicontinuous regime. Cultivations were performed under different conditions, in an Air Lift reactor, and the effects of the factors were evaluated: slurry concentration (SC), CO2 concentration in the gas stream (CC), aeration flow in the reactor (AF) and flow of the feed stream (Q). The Taguchi L9 orthogonal arrangement was used to evaluate the effects of these four factors on the following response variables: rheological parameters (behavior index and consistency index) and productivity in: Biomass (BP), Lipid (LP), Reducing Sugars (RSP) and Proteins (PP). The results showed that the use of the reactor in a semicontinuous regime contributed to the increase in lipid and protein contents by about 30% compared to the results obtained in the batch regime. In contrast, effluent treatment in the semi-continuous regime was less effective, with a reduction in the COD value by 17%, which is 76% lower than the minimum reduction obtained in the batch regime.
In addition, it was also found that, while not increasing the production of reducing sugars, the semi-continuous regime promoted a maximum sugar content 38% higher than that found in the batch regime. After the statistical analysis, it was observed that the leachate concentration was the most influential factor in the analysis of the cellular chemical composition, being significant in the yield analysis of lipids, proteins and reducing sugars.
In the statistical analysis of rheological parameters, the aeration flow was the most influential factor, being significant in the behavior index analysis and relevant in the consistency index analysis. Regarding these parameters, it was observed that the suspension of microalgae showed the behavior of a dilating fluid, a behavior also found by several authors in the literature. The experimental work developed allowed to fully evaluate the influence of several process factors, as well as the influence of the cultivation systems, on the cellular chemical composition and the rheological parameters of the microalgae suspension, enabling new lines of research that may add value to results obtained.
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Papers by Wallyson Ribeiro Dos Santos
suspensions of Chlorella minutissima cultivated in slurry (landfill leachate) in reactors
operated in batch and semicontinuous regime. Cultivations were performed under different conditions, in an Air Lift reactor, and the effects of the factors were evaluated: slurry concentration (SC), CO2 concentration in the gas stream (CC), aeration flow in the reactor (AF) and flow of the feed stream (Q). The Taguchi L9 orthogonal arrangement was used to evaluate the effects of these four factors on the following response variables: rheological parameters (behavior index and consistency index) and productivity in: Biomass (BP), Lipid (LP), Reducing Sugars (RSP) and Proteins (PP). The results showed that the use of the reactor in a semicontinuous regime contributed to the increase in lipid and protein contents by about 30% compared to the results obtained in the batch regime. In contrast, effluent treatment in the semi-continuous regime was less effective, with a reduction in the COD value by 17%, which is 76% lower than the minimum reduction obtained in the batch regime.
In addition, it was also found that, while not increasing the production of reducing sugars, the semi-continuous regime promoted a maximum sugar content 38% higher than that found in the batch regime. After the statistical analysis, it was observed that the leachate concentration was the most influential factor in the analysis of the cellular chemical composition, being significant in the yield analysis of lipids, proteins and reducing sugars.
In the statistical analysis of rheological parameters, the aeration flow was the most influential factor, being significant in the behavior index analysis and relevant in the consistency index analysis. Regarding these parameters, it was observed that the suspension of microalgae showed the behavior of a dilating fluid, a behavior also found by several authors in the literature. The experimental work developed allowed to fully evaluate the influence of several process factors, as well as the influence of the cultivation systems, on the cellular chemical composition and the rheological parameters of the microalgae suspension, enabling new lines of research that may add value to results obtained.
suspensions of Chlorella minutissima cultivated in slurry (landfill leachate) in reactors
operated in batch and semicontinuous regime. Cultivations were performed under different conditions, in an Air Lift reactor, and the effects of the factors were evaluated: slurry concentration (SC), CO2 concentration in the gas stream (CC), aeration flow in the reactor (AF) and flow of the feed stream (Q). The Taguchi L9 orthogonal arrangement was used to evaluate the effects of these four factors on the following response variables: rheological parameters (behavior index and consistency index) and productivity in: Biomass (BP), Lipid (LP), Reducing Sugars (RSP) and Proteins (PP). The results showed that the use of the reactor in a semicontinuous regime contributed to the increase in lipid and protein contents by about 30% compared to the results obtained in the batch regime. In contrast, effluent treatment in the semi-continuous regime was less effective, with a reduction in the COD value by 17%, which is 76% lower than the minimum reduction obtained in the batch regime.
In addition, it was also found that, while not increasing the production of reducing sugars, the semi-continuous regime promoted a maximum sugar content 38% higher than that found in the batch regime. After the statistical analysis, it was observed that the leachate concentration was the most influential factor in the analysis of the cellular chemical composition, being significant in the yield analysis of lipids, proteins and reducing sugars.
In the statistical analysis of rheological parameters, the aeration flow was the most influential factor, being significant in the behavior index analysis and relevant in the consistency index analysis. Regarding these parameters, it was observed that the suspension of microalgae showed the behavior of a dilating fluid, a behavior also found by several authors in the literature. The experimental work developed allowed to fully evaluate the influence of several process factors, as well as the influence of the cultivation systems, on the cellular chemical composition and the rheological parameters of the microalgae suspension, enabling new lines of research that may add value to results obtained.