Vapor liquid equilibrium behavior of aqueous ethanol solution during vacuum coupled simultaneous saccharification and fermentation.

The data on ethanol-water vapor-liquid equilibrium in the presence of cellulase enzyme, nutrients, yeast, and rice straw indicated a substantial increase in ethanol concentration in vapor phase at reduced pressures. Maximum relative volatility of ethanol in the presence of added components is approximately twice that of a pure ethanol-water system. The equation correlating the activity coefficient and ethanol concentration in the liquid phase adequately represents the equilibrium behavior.

Immobilized cell cross-flow reactor.

A cross-current flow reactor was operated using sodium alginate gel entrapped yeast cells under growth conditions. Micron-sized silica, incorporated into the biocatalyst particles (1 mm mean diameter) improved mechanical strength and internal surface adhesion. The process showed decreased productivity and stability at 35 degrees C compared to the normal study done at 30 degrees C. The increased number of cross flows diminish the product inhibition effect. The residence time distribution shows that the cross-flow bioreactor system can be approximated to either a train of backmixed fermentors in series or a plug flow fermentor with moderate axial dispersion.

Analysis of a theoretical model for anisotropic enzyme membranes application to enzyme electrodes.

A theoretical model of diffusion and reaction in an anisotropic enzyme membrane is presented with particular emphasis on the application of such membranes in enzyme electrodes. The dynamic response of systems in which the kinetics are linear, which comprises the practical operating regime for enzyme electrodes in analysis, is investigated via an analytic solution of the governing differential equations. The response is presented as a function of a single dimensionless group, Μ, that is the membrane modulus.