Artículos de Interes

Hydrodynamics and Mass Transfer Simulation in Airlift Bioreactor with Settler using Computational Fluid Dynamics

In this work, the effect of inlet-gas superficial velocity over the circulation liquid velocity, gas holdup and mass transfer, from an airlift bioreactor with settler were studied by Computational Fluid Dynamics (CFD) model- ing and contrasted with experimental results. Multiphase mixture model and κ-ε turbulence model were used to describe the two phases gas-liquid flow pattern in airlift bioreactor. The hydrodynamic parameters such as liquid circulation velocity and gas holdup were computed by solving the governing equations of continuity, moment and turbulence transport using the finite volume method. Global mass transfer coefficient was eval- uated through the Higbie’s penetration theory and the two-phase fluid dynamic theory. Comparison between our numerical data and experimental data previously reported in the literature was done. Numerical and ex- perimental data were very close, and the differences found were discussed in terms of the limitations of this study.

Fuente: ResearchGate

Microbial bioethanol production from Agave tequilana leaves juice sugars: Process variable optimization and kinetic modeling

This study focuses on the valorization of Agave tequilana leaves through bioethanol production from juice sugars. Optimal cultivation conditions were determined using a Taguchi orthogonal array design to maximize bioethanol production by Saccharomyces cerevisiae BEL6 61003. The optimal conditions included reducing sugars at 120 g/L, air flow at 0.5 vvm; agitation at 300 rpm, and pH at 4.5. Under these conditions, the maximum bioethanol concentration reached 43.26 ± 2.20 g/L, with a productivity (rP) of 2.4 ± 0.12 g/L·h and a yield of 43 %. A mathematical model was developed to describe the dynamics of the fermentation process under optimal conditions, comparing the kinetic equations of Moser-Boulton and Moser-Loung. The simulations strongly fit the experimental data, with coefficient of determination (R2) values reaching 0.96 for both models. The selection of the best model was assessed using the Akaike Information Criterion (AIC), favoring the Moser-Boulton equation as the more effective model.

Fuente: ScienceDirect

Fermentable Sugars Production by Enzymatic Processing of Agave Leaf Juice

The Mexican mezcal industry annually processes approximately 2.92
105 t of mezcal agave, generating roughly 1.46
105 t of agave leaves per year, which represents a potential carbon source of at least 8170 t via enzymatic processing of agave leaf juice. This carbon source is considered an attractive alternative to produce biofuels and/or chemical products since it is produced and used without adversely affecting the environment. The aim of this investigation was to determine the effect of temperature, pH, enzyme concentration, and bioreaction time on the enzymatic hydrolysis of agave leaf juice enriched in fructan to maximize the fermentable sugars production from three varieties of mezcal agave, using a low-cost commercial brand of hydrolase. This process generated a sugar-enriched juice of 80.07–136.12 g/L of reducing sugars. A Box-Behnken experimental design and a mathematical surface response analysis of the hydrolysis were used for process optimization.

Fuente: ResearchGate