Delimiting water in the chromium-induced stabilization of collagen

Industrial processes, such as stabilization of skin matrix using chromium, often consume huge quantity of water resulting in depletion of globally demanded valuable resource. Nevertheless, water is essential for the hydrolysis, diffusion, distribution and fixation of chromium in the collagen matrix. Although greener and sustainable solutions for this industrially important process can be obtained through the use of green solvent such as ethanol, probing the minimum quantity of water required for the chromium-induced stabilization of collagen matrix is defied for several years. Here, we show that a minimum of 55–65% internal water content within the collagen matrix is necessary for making chrome tanned leathers through lyophilization technique. The amount and distribution of chromium in the leather decreases as a linear function of internal water content in the skin matrix (from 65 to 15%) with increasing lyophilization time as demonstrated through optical and electron microscopic analyses coupled with energy dispersive x-ray microanalysis.