Abstract

In this paper we present experimental results on the hydrolysis of chrome tanned shavings. It was observed that it is possible to remove chromium down to negligible values (less than 0.1 ppm) when hydrolysis is performed by heating the shavings at 80°C in calcium oxide liquors using the following weight proportions: 0.08 to 0.1 parts CaO, 1 part dried chrome shavings (equivalent to 2 parts wet shavings), 10 parts water. A protein concentrate containing about 80% crude protein and 25% essential amino acids was obtained. An animal nutrition program to study the possible uses of this product was initiated. To obtain enough protein concentrate for this program a pilot plant has been designed and built. Chicken feeding results have shown that the nutritional value of hydrolysed leather meal is nearly one half of the nutritional value of 44% protein soybean oil meal and, when used in rations up to a level of 5% has not caused any loss of appetite or visible metabolic problems to the animals.