Wangjun Lee

MODELING OF SOYBEAN OIL BED EXTRACTION WITH SUPERCRITICAL CARBON DIOXIDE

Dry-milled soybeans are extracted with supercritical carbon dioxide at pressures 270 to 375 atm, temperature 50 to 70‡C, solvent flow rates 0.025 to 0016 cm/sec as a linear velocity in the bed-at supercritical state, and three types of soybean particle size in the range 0.05 to 0.2828 cm.Under these conditions, extraction rates of soybean oil from solid substrates in a fixed bed (1.1 mm I.D. x 200 mm Height) have been determined.The extraction rates were constant during the initial extraction period where the film resistance controls the rates, and then, the rales shifted to time-dependent diffusion controlling mass transfer mode. To correlate these features, mass transfer calculations were carried our for the constant rate period and the subsequent unsteady mass transfer rate period, respectively.

Diagnosis of thermodynamic efficiency in heat integrated distillation

For the systematic diagnosis of the thermodynamic efficiency in dual column distillation with heat integration of practical modes, a computing scheme is developed in conjunction with the method of calculation of exergy and the modularized reduced-order model, which are discussed elsewhere by the present authors [1,2]. The thermodynamic efficiencies of 9 types of heat integration modes are actually calculated and compared with that of a distillation column without heat integration using 3 different kinds of hydrocarbon mixtures, i.e., tertiary, quaternary, and octanary.The results show that the separation energy demand can be reduced by 15% when single heat integration through the reboiler of the first column is made, and about 20% when dual integration through the condenser and the reboiler of the first column is made.

Microbial production of uracil by an isolated Methylobacterium sp. WJ4 using methanol

In this study, we report the production of uracil from methanol by an isolated methylotrophic bacterium, Methylobacterium sp. WJ4. The use of methanol as alternative carbon feedstock is attractive option in biotechnology. As a feedstock of biotechnological processes, methanol has distinct advantages over methane. This is not only due to physical and chemical considerations, but also to the properties of the pertinent organisms. Besides, with a wide array of biological activities and synthetic accessibility, uracil is considered as privileged structures in drug discovery. Uracil analogues have been applied to treatments of patients with cancer or viral infections. In this respect, it is meaningful to produce uracil using methanol. The effect of process parameters and methanol concentration for uracil production were investigated and optimized. Uracil production was remarkably increased to 5.76mgg cell dry weight-1 in optimized condition. The results were significant for further understanding of methylotrophic bacteria on uracil production.

Production of uracil from methane by a newly isolated Methylomonas sp. SW1

Methane is an abundant, inexpensive one-carbon feedstock and one of the most powerful greenhouse gases. Because it does not compete with food demand, it is considered a promising carbon feedstock for the production of valuable products using methanotrophic bacteria. Here, we isolated a novel methanotrophic bacterium, Methylomonas sp. SW1, from a sewage sample obtained from Wonju City Water Supply Drainage Center, Republic of Korea. The conditions for uracil production by Methylomonas sp. SW1, such as Cu2+ concentration and temperature were investigated and optimized. As a result, Methylomonas sp. SW1 produced uracil from methane as a sole carbon source with a titer of 2.1mg/L in 84h without genetic engineering under the optimized condition. The results in this study demonstrate the feasibility of using Methylomonas sp. SW1 for the production of uracil from methane. This is the first report of uracil production from gas feedstock by methanotrophic bacteria.