ECO-FRIENDLY RETANNING APPLICATIONS: ROLE OF TRANSGLUTAMINASE ENZYME (TGase) IN POST TANNING PROCESSES FOR TANNERY POLLUTION LOAD REDUCTION

Tanning industry is under increasing pressure owing to the environmental polution arising from leather manufacturing processes. Clean manufacturing processes are of vital importance in order to minimize the effects of the manufacturing process and product on the environment. In clean manufacturing processes, the use of enzymes or enzyme aided methods instead of the traditional technologies look promising among the new alternative technologies targeting the minimization of environmental polution. Transglutaminase enzyme(TGase) is a transferase class enzyme which is commonly used in food manufacturing to change the functional properties of the proteins. The most crucial characteristic feature of TGase enzyme is that the increase in the generation of cross links. In this study, the possible use of TGase enzyme in retannage process was investigated, and the effects of TGase enzyme on the properties of the leather and the pollution load of the process wastewaters was presented. Three different groups was formed and in the first group, the optimum TGase proportion was determined by means of using a variety of 1, 2, and 3% TGase enyzme respectively. In the second group, during the retannage process no filling agents were used in fatliquoring and dyeing processes. Where as in the third group a traditional retannage method was performed. In all three groups the fatliquoring and dyeing processes were carried out by the same procedure. The pollution load of the wastewaters, the hydrothermal stability of the leathers, color properties, tensile strength, elongation at break and tear load and organoleptic properties were investigated for each group. The result of the study has shown that the enzyme aided retannage method was improved the physical properties of the leathers in comparison to the other two methods employed. As for the hydrothermal stability of the leathers; the stability was found to be higher in the samples aided by TGase enzyme. The most remarkable result among the methods was obtained by the pollution load of the wastewaters.. It has been revealed that the use of TGase enzyme in retannage process was reduced the demand of chemical oxygen(COD) by a rate of 47% and the total nitrogen by a rate of 50.4% in contrast with the traditional retannage method.