ABSTRACT. Glycerol is the principal byiodiesel production worldwide has been on an exponential growth curve over the past several years. The principal by-product of this production is glycerol, also known as glycerin. It occurs in vegetable oils at a level of approximately 10% by weight. For each gallon of biodiesel produced, approximately 0.3 kg (0.66 lb) of crude glycerol accompanies. Such crude glycerol possesses very low value because of the impurities. As the demand and production of biodiesel grows, the quantity of crude glycerol generated will be considerable, and the utilization of it will become an urgent topic. The make-up of crude glycerol varies depending on the parent feedstock and the biodiesel production process. Before the crude glycerol can be considered for possible value-added utilizations, it is necessary to characterize the crude glycerol on its physical, chemical, and nutritional properties.Most industrial biodiesel processes utilize a 6-to-1 molar ratio of alcohol to oil, which is an excess of 100%, in order to drive the reaction to completion. Most of the excess alcohol (up to 80%) will end up in the glycerol layer after the reaction. As a minimum effort, producers will recover this alcohol for reuse. Further refining of the crude glycerol will depend on the economy of production scale and/or the availability of a glycerol purification facility. Larger scale biodiesel producers refine their crude glycerol and move it to markets in the food, pharmaceutical, and cosmetic industries.

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B iodiesel is gaining recognition as a renewable alternative to diesel fuel. One step toward commercialization of biodiesel is establishing how well it stores and what affect storing for long periods has on the performance of the fuel. The problems of fuel deterioration with biodiesel during storage are expected to be more severe than for commercial diesel fuel. Although vegetable oils contain natural antioxidants, their high degree of unsaturation makes them susceptible to gum formation. Since fuel deterioration occurs mainly by oxidative polymerization leading to gum formations one purpose of this study was to determine the rate of oxidative polymerization for different fatty acid esters prepared from rapeseed, as effected by container types, and environments. Peroxide values measure the levels of the oxidation products in the samples. Another purpose of this study was to use short term engine coking and torque test procedures to determine whether the presence of the oxidation products affected the engine performance.

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Serum gamma glutamyl transpeptidase (GGT) levels in blood samples taken from normal calves which bad suckled colostrum were much higher than those found in healthy adult cattle. Levels of over 60 times the normal adult level were observed. These high levels of GGT took approximately 5 weeks to decline to adult values. Calves which appeared to have not received or absorbed colostrum had GGT levels which would be considered normal in adult cattle. A calf with serum gamma globulin levels which indicated an intermediate amount of colostrum absorption had a level of GGT which was intermediate between that expected for normal adult cattle and that found in calves which had more fully absorbed colostrum. The mean GGT level observed in colostrum from 6 newly-calved cows was over 800 times the mean serum GGT level of the same 6 cows. It therefore appears most likely that GGT is concurrently absorbed with colostrum by calves and this gives rise to the very high levels seen in normal calves. Calves with very high levels of serum GGT also had raised levels of alkaline phosphatase (AP) which slowly declined but never reached normal adult levels within the 53-day period of observation. It therefore appears that high levels of both GGT and AP are achieved by calves at the time of colostrum absorption and it is concluded that clinical interpretation of serum GGT and AP levels in young calves is closely dependent upon parallel knowledge of their serum gamma globulin levels.