Experiments on the role of water in petroleum formation

Immobilized lipase activity is studied in organic solvent systems of controlled water content under the influence of a variety of reaction parameters, such as temperature, relative humidity, substrate concentrations, and type of fatty acid used. Control of the amount of water in the reaction system was found to be a valuable tool for the orientation of the reaction process and for the determination of the final reaction products. The properties of the immobilized lipase were studied using the interesterification of triolein and palmitic acid as the model system.

Lipase-catalyzed ester exchange reactions in organic media with controlled humidity.

We demonstrate a very low temperature membrane-free desalination technology, using directional solvents capable of extracting pure water from a salt solution without themselves dissolving in the recovered water. The recovered water contains negligible residual solvent and meets WHO and EPA salinity standards. This process is demonstrated to function effectively at temperatures as low as 40 °C, thus opening up a way to utilize lower temperatures, which may be obtained inexpensively from terrestrial or solar energy or by scavenging waste heat.

Very low temperature membrane-free desalination by directional solvent extraction

Summary
The experimental results of studies on the heat resistance of Bacillus subtilis spores in the model-systems described in the first part of this study (Senhaji & Loncin, 1977) are shown to be in accord with the results of numerical simulation. This confirms the hypothesis that the heat protection phenomenon of fats is due to reduced water activity in the fat during heating.

A second and direct experimental verification allows the presentation of guidelines permitting the occurrence of the phenomenon to be predicted.

The protective effect of fat on the heat resistance of bacteria (I)

Continuous hydrolysis of triglyceride in organic solvent systems using Rhizopus arrhizus mycelia as a source of insolubilized lipase has been studied in packed-bed and stirred-tank reactors. Typically a packed bed reactor containing 1 g of mycelia fed at 1 mL/min with a solution of 2.5% (w/v) olive oil in di-isopropyl ether gave a fatty acid yield of 45% at 30°C. The optimum water concentration was found to be 0.17% (w/v) except under conditions of high oil feed concentration and high yield where no optimum was established. No temperature optimum was observed over the range 20–55°C. Calculated activation energies of 13–20 kJ/mol, depending on temperature, were lower, while Km(app) values of 0.1–0.3M were higher than those for hydrolysis in conventional aqueous emulsion systems. No evidence of any significant diffusional limitation, which could account for these values, was obtained. The mycelia showed a loss of activity of 0.6–1.0%h at 30°C. The packed bed proved markedly superior to the stirred tank for this system.

Hydrolysis of triglyceride by solid phase lipolytic enzymes of Rhizopus arrhizus in continuous reactor systems

The solubilities of water in rapeseed oil, coconut oil, and a palm-coconut oil mixture were determined at temperatures of 60C, 80C, and 100C. Oil samples were equilibrated with water vapor under conditions of constant temperature and humidity. The equilibrium water content was determined by means of the Karl Fischer titration method. The solubility was found to be independent of the type of oil when expressed in terms of the mole fraction. An equation relating solubility and temperature is given.

M. H. Hilder

Papers

The solubility of water in edible oils and fats