Lactic acid production from glucose and xylose using the lactogenic Escherichia coli strain JU15: Experiments and techno-economic results.

In this work, d-lactic acid production was evaluated from a simulated hydrolysate of corn stover (32 g/L xylose, 42 g/L glucose) with the metabolically engineered Escherichia coli strain JU15. Based on the experimental results, a technical and economic analysis of the entire process was performed using the Aspen Plus software. As a result, it was possible to show that the strain can efficiently produce lactic acid from both sugars, reaching a final concentration of 40 g/L and a yield of 0.6 g lactic acid/g sugars. The process is economically viable at higher scales of 1000 tons/day. The cost distribution is influenced by the scale of the process; on a larger scale, the cost of raw materials represents a higher percentage of total cost than it does on smaller scales. The use of a metabolically engineered strain allows a better use of the sugars obtained from agroindustrial residues.

Techno-economic and environmental assessment of biogas production from banana peel (Musa paradisiaca) in a biorefinery concept.

Two scenarios for the biogas production using Banana Peel as raw material were evaluated. The first scenario involves the stand-alone production of biogas and the second scenario includes the biogas production together with other products under biorefinery concept. In both scenarios, the influence of the production scale on the process economy was assessed and feasibility limits were defined. For this purpose, the mass and energy balances were established using the software Aspen Plus along with kinetic models reported in the literature. The economic and environmental analysis of the process was performed considering Colombian economic conditions. As a result, it was found that different process scales showed great potential for biogas production. Thus, plants with greater capacity have a greater economic benefit than those with lower capacity. However, this benefit leads to high-energy consumption and greater environmental impact.

MEDICIÓN DEL EQUILIBRIO LIQUIDO-VAPOR DEL SISTEMA METANOL-ACETATO DE METILO A 580 mmHg / EXPERIMENTAL LIQUID VAPOUR EQUILIBRIUM OF THE BINARY SYSTEM METHANOL-METHYL ACETATE AT 580 mmHG

En este trabajo se midió experimentalmente el equilibrio líquido vapor para el sistema binario Metanol - Acetato de Metilo a 580 mmHg. Las mediciones experimentales fueron realizadas utilizando un equipo con recirculación tipo Cottrell. Los datos obtenidos fueron comparados con los resultados adquiridos de la simulación del equilibrio líquido vapor del sistema bajo estudio. En la simulación se empleó el modelo de actividad NRTL para representar la no idealidad de la fase líquida (con parámetros encontrados en la literatura), y la ecuación de estado de Hayden O´Connel para la no idealidad de la fase vapor. De igual manera, se correlacionaron los datos para encontrar nuevos parámetros del modelo de actividad en NRTL. Además, a partir de datos experimentales medidos a 760 mmHg encontrados en la literatura para el sistema estudiado, se verificó la ley de Vresky, la cual permite sin necesidad de cálculos rigurosos predecir la dirección de desplazamiento de un azeótropo binario cunado se varía la presión del sistema.

In this work the liquid - vapor binary equilibrium for the system Methanol - Methyl Acetate was measured at 580 mmHg using equipment with recirculation that also can be employed for reactive mixtures. The obtained data was compared with liquid vapor equilibrium prediction employing NRTL activity model for the liquid phase (using parameters found in the literature) and the Hayden O´Connel's equation of state for the non ideality of vapor phase. New parameters of NRTL activity model were obtained. The Vresky law that permits without rigorous calculations to predict qualitatively the displacement of binary azeotropes by pressure changes was confirmed, using various experimental data that is reported in the literature for this system at 760 mm Hg.