Enzymatic Extraction and Characterization of Pectin from Cocoa Pod Husks (Theobroma cacao L.) Using Celluclast® 1.5 L.

Cocoa pod husks are a waste generated during the processing of cocoa beans. We aimed to explore the enzymatic extraction of pectin using cellulases. The extraction process was optimized using a central composite design (CCD) and analyzed by response surface methodology (RSM). The parameters optimized were feedstock concentration (%), enzyme dosage (µL/g), and time (h). Three dependent variables were studied: pectin yield (g/100 g dry husk) (R2 = 97.02), galacturonic acid content (g/100 g pectin) (R2 = 96.90), and galacturonic acid yield (g/100 g feedstock) (R2 = 95.35). The optimal parameters were 6.0% feedstock concentration, 40 µL g-1 of enzyme, and 18.54 h, conditions that produced experimentally a pectin yield of 10.20 g/100 g feedstock, 52.06 g galacturonic acid/100 g pectin, and a yield 5.31 g galacturonic acid/100 g feedstock. Using the chemical extraction method, a yield of 8.08 g pectin/100 g feedstock and a galacturonic acid content of 60.97 g/100 g pectin were obtained. Using assisted sonication, a pectin yield of 8.28 g/100 g feedstock and a galacturonic acid content of 42.77 g/100 g pectin were obtained. Enzymatically optimized pectin has rheological and physicochemical features typical of this biomaterial, which provides an interesting alternative for the valorization of cocoa husks.

Caracterización de la Opuntia ficus-indica para su uso como coagulante natural / Characterization of Opuntia ficus-indica for using as a natural coagulant

Actualmente municipios de la Costa Atlántica Colombiana no cuentan con suministro de agua potable. La aplicación artesanal de la Tuna (Opuntia ficus-indica) como coagulante es una práctica tradicional en comunidades rurales. En esta investigación se realiza la caracterización del tallo de la Tuna que crece de manera silvestre en el departamento de Bolívar, y del polvo extraído de esta planta, con el fin de identificar componentes asociados a su poder coagulante para la remoción de turbidez y de color en aguas crudas. Las pencas de la planta se sometieron a operaciones de corte, pelado, secado, molienda, tamizado y despigmentado para obtener el coagulante. El rendimiento del proceso global fue de 65g de coagulante/Kg de material vegetal. Los resultados indicaron que la penca contiene alto porcentaje de humedad y pequeñas proporciones de saponinas, flavonoides, sales minerales de calcio y hierro; lo cual permitió concluir que estos metabolitos y sales no son los responsables de su poder coagulante debido a las cantidades poco significativas en las que se encuentran. Se consideró que otras especies química tales como el ácido poligalacturónico y compuestos algínicos son realmente los que le confieran la cualidad al biomaterial. También, se evaluó el poder coagulante del material extraído, se analizó el efecto de tres dosis sobre el color, la turbidez y el pH del agua tratada. Los resultados indicaron que tiene la capacidad de remover 50% del color y 70% de turbidez de aguas crudas con alta turbidez inicial, y que no altera significativamente su pH.

Currently, municipalities in the Colombian Atlantic Coast do not have potable water supply. The implementation of the Tuna as a coagulant is a traditional practice in rural communities, but is used in craft way. In the present investigation, the characterization of the stalk of Tuna (Opuntia ficus-indica) growing in the wild in the Bolivar department, and of the powder extracted from this plant was realized with the purpose to identify components associated with its coagulant power to remove color and turbidity in raw water. The stalks of this plant were subjected to cutting, peeling, drying, grinding, sieving and depigment for obtaining the coagulant. The overall process yield was 65g of coagulant/kg of vegetal material. The results also indicated that the stalk of Tuna contains high moisture content and low amounts of saponins, flavonoids, minerals, calcium and iron. It allowed concluding that these metabolites and salts are not responsible of the coagulant power of plant due to the insignificant amounts in which they are present. Therefore, it is presumed that other chemical species such as polygalacturonic acid and alginic compounds are those that confer the quality to the biomaterial. Also, the coagulant power of extracted material was evaluated. The effect of three dosis on the color, turbidity and pH of trated water was analized. The results indicated that it has the capacity to remove 50% of color and 70% of turbity from crude water with high initial turbidity. Also, it does not affect significantly its pH.

Influencia de las regiones de estabilidad del biorreactor en la producción eficiente de alcohol carburante / Influence of bioreactor stability regions in the efficient production of fuel ethanol

Colombia ha desarrollado un proyecto ambicioso en la producción de alcohol carburante, y actualmente es uno de los países líderes de América Latina en la producción de biocombustibles. No obstante, algunas de sus plantas industriales productoras de etanol presentan problemas durante el arranque y la operación de los fermentadores, que afectan adversamente la productividad del proceso global. Estudios teóricos y experimentales demuestran que el comportamiento dinámico del proceso depende de los fenómenos de estabilidad que exhibe el sistema. En este trabajo se muestra la influencia de las regiones de estabilidad sobre la eficiencia del proceso tomando como criterios de evaluación índices de impacto económico y ambiental. Para esto, se realizó un análisis de estabilidad donde se tomó como parámetro de operación principal la velocidad de dilución. Se empleó un programa propio desarrollado sobre Matlab® para generar diagramas de bifurcación y de fase. El algoritmo de reducción de residuos (WAR) desarrollado por la Agencia de Protección Ambiental de los Estados Unidos, y el software SuperPro Designer®, fueron utilizados respectivamente para hacer la evaluación ambiental y económica del proceso. Como resultado, se evidenció que los procesos continuos de fermentación se pueden llevar a cabo en diferentes regiones de estabilidad, y que las variables de respuesta, tales como el rendimiento, dependen de la región de operación seleccionada. Finalmente, se llegó a la conclusión de que la evaluación de la estabilidad de los procesos de fermentación debe incluirse en las etapas de diseño de bioprocesos para garantizar su buen desempeño.

Colombia has developed an ambitious project to produce fuel ethanol. Nowadays, Colombia is one of the leading countries in Latin America for the biofuels production. However, some of its industrial plants producing ethanol present problems during the startup and the operation of fermenters, which adversely affects the productivity of the global process. Theoretical and experimental studies show that the process’ dynamic behavior depends on the stability phenomenon exhibited by the system. This work shows the influence of the stability regions on the process’ efficiency. For this, economic and environmental index were used. A stability analysis was carried out. The dilution rate was selected as the main operating parameter. An own program developed on Matlab® was used to generate bifurcation diagrams and phase diagrams. The Waste Reduction Algorithm (WAR) developed by the Environmental Protection Agency of the United States, and the SuperPro Designer® software were used for estimating the environmental and economic assessment of the process. As a result, it was shown that continuous fermentation processes can be carried out in different stability regions. Likewise, it was shown that the response variables, such as the yield, depend on the selected operating region. Finally, it was concluded that the evaluation of fermentation processes’ stability must be included in the stages for designing of bioprocess in order to ensure a good performance.

Importance of stability study of continuous systems for ethanol production.

Fuel ethanol industry presents different problems during bioreactors operation. One of them is the unexpected variation in the output ethanol concentration from the bioreactor or a drastic fall in the productivity. In this paper, a compilation of concepts and relevant results of several experimental and theoretical studies about dynamic behavior of fermentation systems for bioethanol production with Saccharomyces cerevisiae and Zymomonas mobilis is done with the purpose of understanding the stability phenomena that could affect the productivity of industries producing fuel ethanol. It is shown that the design of high scale biochemical processes for fuel ethanol production must be done based on stability studies.