Production of Ethanol from Sweet Sorghum Juice Using VHG Technology: A Simulation Case Study

The aims of this study were to develop the kinetic model and determine kinetic parameters describing ethanol production from sweet sorghum juice using very high gravity technology in the batch fermentation of Saccharomyces cerevisiae NP01. The obtained experimental data were tested with four different types of model, based on the experimental data, accounting for the substrate limitation, substrate inhibition, product inhibition, and the combination of those three effects, respectively. The optimization technique to find kinetic parameters was non-linear regression using Marquardt method performed through numerical procedure. The chosen model with its kinetic parameters obtained in the batch mode was validated and tested against the other independent experimental data in the small batch-scale and large-scale fermenter, in order to investigate the applicability and scale-up effect of the model, respectively. Then, the obtained model with its parameters was applied in the simulations of the continuous and fed-batch operations to examine the concentration profiles of fermentation components with the variations in operating parameters such as the dilution rate, feed-flow rate, start-up time, and feed concentration. The results indicated that the kinetic model (the substrate limitation with substrate and product inhibition effects) was suitable to describe ethanol fermentation. In the continuous mode, using the dilution rate of 0.01 h^?1, the maximum ethanol concentration obtained was, approximately, 90 g/l whereas the simulated results from the fed-batch operation revealed that the maximum ethanol concentration at quasi-steady state condition was, approximately, 96 g/l. The start-up time of 21 h was the fastest time to reach the steady-state and quasi-steady state for both the continuous and fed-batch modes, respectively.     

New products

Arosy future was forecast for Brookhaven National Laboratory's (BNL) user facilities at the first-ever joint meeting of the user communities for the National Synchrotron Light Source (NSLS) and the Center for Functional Nanomaterials (CFN), held May 15–17, 2006.     

Phase equilibrium modeling of triglycerides in supercritical fluids

To design a reactor and separator for a supercritical biodiesel process, phase equilibria of multi-component mixtures in supercritical fluids should be determined using group contribution with association equation of state (GCA-EOS) as a thermodynamics method. The model is considered for two systems of reactants and products. System 1 is comprised of methanol and triglycerides from two sources (palm and Jatropha oils); and System 2 is unconverted methanol, FAME (product) and glycerol (by-product). Pressure and temperature diagrams were developed at different mole fraction of methanol (x_MeOH). As x_MeOH increased, the critical temperature (T_c) and pressure (p_c) increased. The increasing temperature causes the immiscibility region and the amount of methanol at the plait point to decrease. The maximum plait point pressure was observed at 19.20 MPa for palm and 19.33 MPa for Jatropha oil systems.     

Diffraction‐based automated crystal centering

A fully automated procedure for detecting and centering protein crystals in the X‐ray beam of a macromolecular crystallography beamline has been developed. A cryo‐loop centering routine that analyzes video images with an edge detection algorithm is first used to determine the dimensions of the loop holding the sample; then low‐dose X‐rays are used to record diffraction images in a grid over the edge and face plane of the loop. A three‐dimensional profile of the crystal based on the number of diffraction spots in each image is constructed. The derived center of mass is then used to align the crystal to the X‐ray beam. Typical samples can be accurately aligned in ～2–3 min. Because the procedure is based on the number of `good' spots as determined by the program Spotfinder, the best diffracting part of the crystal is aligned to the X‐ray beam.