DEGRADATION OF REACTIVE DYES USING IMMOBILIZED PEROXIDASE PURIFIED FROM NIGELLA SATIVA

The present study was aimed to exploit the free and immobilized peroxidase from Nigella sativa seeds to degradation of textile dyes polluting the environment and water. The optimum conditions for extracting the enzyme from the Nigella seeds were determined and the highest specific activity of the enzyme was obtained 1750 units / mg protein when extracting the enzyme from the ground seeds at a ratio of 1:20 (w: v) with sodium acetate buffer at 0.2 M and pH 5.0 for 15 minutes. The enzyme was purified using two steps including the concentration by sucrose and gel filtration by using Sephadex G-150. The results shown an increase in final purification folds 2.8 time with an enzyme yield of 35%. The immobilization of peroxidase were done by entrapment method using Ca- alginate and the immobilization ratio was reached to 49%. The removal efficiency of dyes by crude enzyme (free, immobilized) and partial purified peroxidase were studied with textile dyes such as yellow, red, black and blue dyes at optimum conditions pH 5, temperature 37 degrees C after 3 hr. Maximum removal efficiency of dyes observed with crude peroxidase and reached (76.9, 88.7, 91 and 88) % respectively. These results were close to the efficiency of the purified enzyme in removing the four dyes, while the efficiency of the crude immobilized enzyme in removing the dyes was about (70, 81, 72 and 56.4)%, respectively.