Submitted to: Journal of American Leather Chemists Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/28/2005
Publication Date: 5/1/2006
Citation: Taylor, M.M., Bumanlag, L.P., Marmer, W.N., Brown, E.M. 2006. Use of enzymatically modified gelatin and casein as fillers in leather processing. Journal of American Leather Chemists Association. 101(5):169-178. Interpretive Summary: There has been considerable interest recently in the use of products from renewable resources for the production of goods that were customarily made from petroleum feedstuffs. For example, some of the products that have traditionally been used in leather production to fill the hide to give a more uniform product are petroleum based. As an alternative, prior research from this laboratory demonstrated that gelatin, a by-product from the manufacture of leather, could be treated with a chemical to give a high molecular weight product that could be used as a filler. However, the chemical could be toxic and there was a need to find a more environmentally-benign treatment. We have demonstrated in recent research that a food grade enzyme could be reacted with gelatin (and with casein) to also give polymers with unique properties. In this present study, we treated leather with these new enzymatically-formed products and evaluated their potential as fillers. Compounds were added to the gelatin and casein that have a tendency to fluoresce when exposed to a light at a specific wave length. After application of the gelatin and casein to the leather, the final filled products were examined under a microscope with the capability of seeing this fluorescence. It was demonstrated that these enzymatically prepared products did indeed fill the leather and moreover were bound to the leather and would not easily be removed during further processing.
Technical Abstract: Prior research from this laboratory demonstrated that chemically modified collagen byproducts could be used effectively as fillers during leather processing. The gelatins were reacted with glutaraldehyde and, after application to veiny leather, these highly polymerized gelatins did fill and more importantly were bound to the substrate. The applications were followed by using fluorescently labeled gelatin that was added to a stock solution and the final products were examined under a microscope that had the capability of showing that the gelatins fluoresce. In this present study, fluorescently labeled gelatins were polymerized by using microbial transglutaminase as the cross-linking agent and the reactions took place in either the leather itself or the samples were first prepared and then added to the leather. Furthermore, we wanted to see, based on results from our earlier experiments in which we produced biopolymers from enzyme-modified gelatin and casein, if these products could also be effective fillers. In these experiments, we labeled casein as well as the gelatin. Varying conditions were examined for optimal filling results. The results showed that indeed these enzymatically prepared products could be used effectively as fillers and moreover were bound to the leather and would not easily be removed during further processing.