Sunday, August 12, 2012
Columbia Hall, Terrace Level (Washington Hilton)
Now a day there are some industries characterized by the amount of water that they use, one of this is the textile industry, which consumes large quantities of water and discharges them to the environment, without an efficient treatment causing an environmental problem. Textile dyes are recalcitrant, conventional physical, chemical and biological systems could not remove a large amount of them. In this work we evaluate the effect of tiol over the enzymatic immobilization over silica and in the indigo discoloration rate. Silica crystals were submerged in 2,2´dithiopyridine during two hours at room temperature and washed with ethanol, after that they were submerged in 5,5´dithiobis(2-nitrobenzoic) acid two hours and washed with ethanol and finally submerged in residual culture medium previously ultra-filter to concentrate the proteins (System 1). Other residual culture medium were immobilized on silica using glutaraldehyde as a cross link agent (System 2).
It was evaluated the laccase and peroxidase activity, % of immobilized protein, rate of indigo discoloration and fitotoxicity of the products.
In both systems the protein immobilized and laccase activity were similar, however system 2 had a high peroxidase activity, system 1 discolored a 100 ppm indigo carmine solution in 97 days and system 2 in 84 days. The indigo carmine discoloration products were tested for toxicity assay, products of indigo oxidation with system 2 were non phytotoxic for lettuce seeds, whereas indigo carmine discoloration products using system 1 were phytotoxic.
Application of thiol did not improve the immobilized system neither the indigo carmine oxidation rate.