Hydrolysis of beef tallow by lipase from Pseudomonas sp

The lipase produced by Pseudomonas fluorescens biotype I was selected for hydrolyzing beef tallow at 50-70 degrees C to more than 90% of reaction ratio. Using an amount of lipase sufficient to reach equilibrium, the final reaction ratio was decreased with increasing temperature and the apparent enthalpy of beef tallow hydrolysis obtained by the final reaction ratio was -1.93 x 10(4)cal/mol, and the final reaction ratio also decreased with increasing substrate concentration. The rising time, which is the reaction time up to one-half of the final reaction ratio, decreased remarkably with increasing temperature, and was closely related to the value of the maximum velocity by the Michaelis constant of this lipase. The final reaction ratio increased with increasing lipase amount up to equilibrium. Increasing the lipase above the amount required to reach equilibrium caused a decrease in the rising time. The feasibility of using parameters obtained by a hyperbolic simulation of the progress curve is discussed.

Response and linearity of different lipid compounds when analyzed by thin-layer chromatography with flame ionization detection

The response an linearity were studied for about twenty different types of lipids in a quantitative thin-layer chromatographic system equipped with flame ionization detection (TLC-FID). For most compounds the response showed good linearity with loads from 0.4 to 15 micrograms. The relative response of cholesterol, sterol ester and wax ester in ratio to triglyceride was, however, found to depend on the concentration, and this should be taken into account in quantitative determinations. The relative response of different lipids varied from 0.6 for hydrocarbon to about 1.4 for cholesterol. The application of the TLC-FID technique for skin lipid separations is illustrated.