Study On Extracting High Quality Collagen Protein From Chrome Shavings & Application In Medical Wound Dressing

As the center of leather industry in the world, large amount of protein-containing leather wastes were generated every year. Due to the characteristics of leather making technology in China, over 70% of those wastes contained chrome. Since the components of chrome-free leather wastes were simple, the recycling technology of them had been promoted fully. To those chrome-containing leather wastes, it was difficult to extract high quality collagen protein from them because of the cross linking of chrome between collagen chains, which result in the wasting of useful collagen protein and chromium resources.The main problems limiting the value-added utilization of chrome shavings were the qualities and the obtain ratio of collagen protein, as well as the separation result of chrome and collagen. The present methods had defects of low obtain ratio, high ash and chrome content. In connection with these problems, the thesis invested the extracting processing with alkali systemically. Based on the results of experiments, a gradually extracting method was designed to get high quality collagen protein from chrome shavings. With this method, the obtained collagen protein had low ash content less than 2%, and chrome content 2 ppm, which can fulfill the requirements for using as edible additive.Based on the investigation of extracting process, a new kind of collagen medical wound dressing was made with the obtained collagen protein. Chitosan was introduced to improve the properties of film. The blending properties of collagen protein and chitosan were discussed in this paper. The result of experiments showedthat when the proportion between collagen protein and chitosan was 9:1, the amount of plasticizer and cross linking agent was 60% and 20% respectively, the properties of film could count to the requirements of using as medical wound dressing.The result of applying on animals showed that the wound dressing had good compatibility with skin, without any stimulating reaction. Compared with traditional wound dressing, no inflammations were found. After two weeks, the wound covered with collagen dressing had healed fully. The surface of wound was uniform and no towers were found in surroundings.Results of the research indicated that it was practicable to extracting high quality collagen protein from chrome shavings, and it was feasible to make medical wound dressing with this kind of collagen protein as main material.