The commercial production of chemicals using pathway engineering.

Integration of metabolic pathway engineering and fermentation production technologies is necessary for the successful commercial production of chemicals. The 'toolbox' to do pathway engineering is ever expanding to enable mining of biodiversity, to maximize productivity, enhance carbon efficiency, improve product purity, expand product lines, and broaden markets. Functional genomics, proteomics, fluxomics, and physiomics are complementary to pathway engineering, and their successful applications are bound to multiply product turnover per cell, channel carbon efficiently, shrink the size of factories (i.e., reduce steel in the ground), and minimize product development cycle times to bring products to market.

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.

Diffusional/kinetic analysis of the neurotransmission process at the nerve-muscle junction.

Transmission at the neuromuscular junction is known to comprise the following steps: vesicular release of Ach pulses; transport across the synaptic cleft; partial hydrolysis by Ach-ase; binding to Ach receptors; ion channel opening and closure, and, thereby, alteration of sodium and potassium conductances. Combining these elements, a unified model has been constructed that is effective in describing the relation between neurotransmitter arrival at receptor sites and channel openings, leading to simple relationships for sodium and potassium conduction at the neuromuscular junction. Application of the model to mepc and epp data has been successful.

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.