Recuperación y concentración de proteinas del suero de leche mediante ultrafiltración y nanofiltración.
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Date
2025
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Publisher
Universidad de Concepción
Abstract
La recuperación de elementos valiosos del suero ácido es una práctica poco explorada en la industria láctea debido a sus limitaciones de procesabilidad. Su alta concentración de ácido láctico afecta negativamente la cristalización de la lactosa. Por este motivo, surge la necesidad de evaluar el uso de tecnología de membranas para el tratamiento del suero ácido, con el fin de concentrar proteínas y lactosa y, a la vez, extraer el ácido láctico.
Este estudio se centró en evaluar tres configuraciones de filtración, dos configuraciones combinadas de ultrafiltración (UF) con nanofiltración (NF) y una configuración de nanofiltración directa (UF (10 kDa) + NF2701, UF (100 kDa) + NF2702; y NF2703). Se realizaron mediciones analíticas de proteínas, lactosa, ácido láctico y Demanda Bioquímica de Oxígeno (DBO₅) para analizar el rendimiento de cada sistema. Además, se analizó la influencia de la limpieza química en la recuperación de la permeabilidad de las membranas luego de procesar suero ácido y el permeado proveniente de las etapas de UF.
En relación con la concentración de proteínas, la UF (10 kDa) demostró ser proceso efectivo, se obtuvo un aumento máximo de concentración de 94%, mientras que con UF (100 kDa) el aumento máximo fue de 116,07%. Respecto a la lactosa (LT), ninguna de las configuraciones combinadas permitió alcanzar el aumento de concentración esperado; por el contrario, en el retenido final posterior a la etapa de NF se observó una disminución. En relación con el ácido láctico (AL), el proceso combinado UF (100 kDa) + NF2702 resultó ser más efectivo para reducir su concentración en el retenido final (32–39%.). Sin embargo, la relación AL/LT no fue suficiente para garantizar la pureza necesaria para aplicaciones que exigen lactosa de alta calidad. Todas las membranas resultaron eficientes para la disminución de la DBO₅, alcanzado reducciones superiores al 92%; para mayores reducciones, se sugiere implementar etapas de filtración en serie utilizando membranas de UF (100 kDa).
La operación con suero ácido provocó una disminución considerable de la permeabilidad de las membranas de UF y NF. Los procesos de limpieza implementados lograron recuperar hasta el 89% de la permeabilidad inicial, sin embargo, la limpieza química por sí sola fue ineficiente, por lo que fue necesario adicionar una etapa posterior de hidratación con etanol.
Para estudios posteriores, se sugiere profundizar en el diseño de estrategias de limpieza de membranas más eficaces y menos agresivas, como surfactantes y enzimas, con el fin de evitar incrustaciones por la desnaturalización de proteínas y mejorar la selectividad del sistema para la separación de lactosa y ácido láctico.
The recovery of valuable elements from acid whey is a little-explored practice in the dairy industry due to its processing limitations. Its high concentration of lactic acid negatively affects the crystallization of lactose. For this reason, there is a need to evaluate the use of membrane technology for the treatment of acid whey, to concentrate proteins and lactose while separating lactic acid from them. This study focused on evaluating three filtration configurations: two combined ultrafiltration and nanofiltration configurations and one direct nanofiltration configuration (UF (10 kDa) + NF, UF (100 kDa) + NF, and NF). Analytical measurements of proteins, lactose, lactic acid, and Biochemical Oxygen Demand (BOD) were performed to analyze the performance of each system. In addition, the influence of chemical cleaning on the recovery of membrane permeability after being treated with acid whey and permeate from the UF stages was analyzed. In relation to protein concentration, UF (10 kDa) proved to be an effective process, with a maximum concentration increase of 94%, while with UF (100 kDa) the maximum increase was 116.07%. With regard to lactose (LT), none of the combined configurations achieved the expected increase in concentration; on the contrary, a decrease in the final retention after the NF stage was observed. In relation to lactic acid (LA), the combined UF (100 kDa) + NF2702 process was more effective in reducing its concentration in the final retentate (32–39%). However, the required LA/LT ratio was not sufficient to guarantee the purity required for subsequent applications that demand high-quality lactose. All membranes were efficient in reducing BOD, achieving reductions > 92%. For greater reductions, it is suggested to implement serial filtration stages using UF (100 kDa) membranes. The acid whey treatment caused a considerable decrease in the permeability of the UF and NF membranes. The cleaning processes implemented managed to recover up to 89% of the initial permeability. However, chemical cleaning alone was inefficient, so it was necessary to add a subsequent ethanol hydration stage. For further studies, it is suggested to further develop more effective membrane cleaning strategies, improve the selectivity of the system for the separation of lactose and lactic acid, and explore the possibility of implementing membranes in series to obtain a permeate with a BOD within the permissible limits for subsequent discharge into rivers, lakes, or the sea.
The recovery of valuable elements from acid whey is a little-explored practice in the dairy industry due to its processing limitations. Its high concentration of lactic acid negatively affects the crystallization of lactose. For this reason, there is a need to evaluate the use of membrane technology for the treatment of acid whey, to concentrate proteins and lactose while separating lactic acid from them. This study focused on evaluating three filtration configurations: two combined ultrafiltration and nanofiltration configurations and one direct nanofiltration configuration (UF (10 kDa) + NF, UF (100 kDa) + NF, and NF). Analytical measurements of proteins, lactose, lactic acid, and Biochemical Oxygen Demand (BOD) were performed to analyze the performance of each system. In addition, the influence of chemical cleaning on the recovery of membrane permeability after being treated with acid whey and permeate from the UF stages was analyzed. In relation to protein concentration, UF (10 kDa) proved to be an effective process, with a maximum concentration increase of 94%, while with UF (100 kDa) the maximum increase was 116.07%. With regard to lactose (LT), none of the combined configurations achieved the expected increase in concentration; on the contrary, a decrease in the final retention after the NF stage was observed. In relation to lactic acid (LA), the combined UF (100 kDa) + NF2702 process was more effective in reducing its concentration in the final retentate (32–39%). However, the required LA/LT ratio was not sufficient to guarantee the purity required for subsequent applications that demand high-quality lactose. All membranes were efficient in reducing BOD, achieving reductions > 92%. For greater reductions, it is suggested to implement serial filtration stages using UF (100 kDa) membranes. The acid whey treatment caused a considerable decrease in the permeability of the UF and NF membranes. The cleaning processes implemented managed to recover up to 89% of the initial permeability. However, chemical cleaning alone was inefficient, so it was necessary to add a subsequent ethanol hydration stage. For further studies, it is suggested to further develop more effective membrane cleaning strategies, improve the selectivity of the system for the separation of lactose and lactic acid, and explore the possibility of implementing membranes in series to obtain a permeate with a BOD within the permissible limits for subsequent discharge into rivers, lakes, or the sea.
Description
Tesis presentada para optar al título de Ingeniero/a Civil Químico/a.
Keywords
Suero de leche, Proteínas de la leche, Ácido láctico, Ultrafiltración