Products of enzymatic decomposition of chrome-tanned leather waste

Together with the British Leather Centre Northampton we have been solving the problem of processing tanned waste from tanneries. We have discovered that above all else their enzymatic decomposition is interesting thanks to its low requirements of energy as well as easy and almost perfect separation of Cr3+ compounds from the protein hydrolysate. The use of the resulting protein hydrolysate as a secondary chemical raw material can, in practice, favourably influence the economy of the process. That is why it is necessary to investigate the basic characteristics of this process. Apart from presenting the basic characteristics (solids, ash, nitrogen content), the submitted study evaluates the contents of primary amino groups, which represent the main centre of interaction of the hydrolysate, as well as the average molecular weight of the hydrolysates, and assesses the influence of reaction time on this characteristic. Individual components of the hydrolysate have been separated through acrylamide gel electrophoresis. We have also determined the concentration dependence of the surface tension of aqueous solutions of the hydrolysates. Furthermore we have conducted a basic analysis of the solid phase of the reaction mixture, which consists mainly of inorganic fractions including Cr3+ compounds.