Study On The Staining Of Natural Polyphenol Compounds Based On Biotransformation

Tea pigments are renewable biomass resources that widely existed in natural world,and have application prospect in dozens of industries,such as foodstuff,pharmaceutical,cosmetic as well as dyeing et al.Tea polyphenols could be transformed into tea pigments by employing bioconversion,and the dyeing of fabrics was achieved in this process.Experiment results demonstrated that the dyeing property of protein fiber was better compared to cellulosic fiber.The dominant microorganisms for the preparation of tea pigments were selected by employing microbial fermentation technology,and the biomass as well as the content both tea polyphenols and tea pigments were analyzed during the process of fermentation.Tea pigments could be prepared from colorless tea polyphenols under the catalytic oxidation of laccase as well as crude enzyme generated by Aspergillus niger.Additionally,the relation between tea polyphenols and theaflavin as well as possible enzymatic oxidation mechanism was analyzed during the process of bioconversion.Experiment results demonstrated the content of theaflavin reached the maximum under the catalytic action of laccase 24 hours later,while that reached the maximum under the catalytic action of crude enzyme 48 hours later.Crude enzyme generated by Aspergillus niger was employed to convert tea polyphenols as precursor into pigments via bioconversion and simultaneously the dyeing of fabrics was achieved in this process.Experiment results demonstrated that pigments prepared were able to dye fabrics,and characterized by admirable color fastness.Laccase was able to catalyze precursor tea polyphenols trnsformed into theaflavin,and dyeing of protein fabric was achieved under different conditions of acid and alkali.Experiment results demonstrated dyeing property was better under acidic condition compared to alkaline condition,and fixation rate was the best when pH value was 3.Tea pigments prepared could achieve the dyeing of natural fibers in the paper.Research results indicated the dyed fabrics possessed admirable color fastness,such as rubbing,washing as well as light fastness,and could meet application requirement.Furthermore,the dyeing method presented in this work was a sustainable cleaner production technology since without any chemical reagents were added during the process of preparation and dyeing.