With rising environmental contamination and a movement toward green chemistry, waste recycling, and biomass utilization have become a primary priority for most researchers worldwide. As a result, the goal of this work was to employ banana peels as a free source for the isolation of peroxidase (POD) and polyphenol oxidase (PPO) enzymes, to obtain discharge printing on natural materials dyed with different natural plant extracts such as Ficus benjamina, Psidium guajava leaves, Solanum melongena peel, and Brassica oleracea var. capitata rubra. The enzyme extraction temperature was (25 °C), and the solute-liquid ratio (1:4–w/v) at pH 5.0 after a treatment time of 5 min. The oxidative enzymes are characterized by Gas Chromatography-Mass Spectrometer (GC-MS) Analysis which confirmed the presence of a Retinol component with a Molecular Weight of 286.45 g/mol at a retention time of 14.7 min which is considered evidence of the existence of oxidative enzymes. The activity of oxidative enzymes isolated from banana peel rises with time, with the greatest activity of PPO at 180 s at wavelength 420 nm. While POD reaches its maximum activity at 180 s, at wavelength 436 was detected. These make it possible to be used as a discharge agent. The extracted enzymes are applied to discharge the natural dye from cotton and wool material and compared with conventionally used reducing agents (25 % sodium hydrosulfite) in parallel. The discharge printing process was optimized under various conditions including the effects of enzyme concentration, pH, drying time, temperature, and the effect of mixing with other agents (H2O2, Glucose, and brewer’s yeast). The results indicate that the discharge rates reached about 35–37 % using the enzyme extracted from banana peels at pH 3 for wool samples and pH 5 for cotton ones. Mixing with other reducing or oxidizing agents in different concentrations led to a higher discharge rate, which reached 65–67 %, and different color half-tones were obtained depending on the difference in mixing ratio, concentration, pH, and other factors affecting color removal. It was also observed that there was a slight increase in the tensile strength for all wool printed samples ranging from 1 % to 4 %, except the wool sample that was dyed with Psidium guava leaves extract. While the tensile strength of cotton printed samples decreased but in an acceptable range. Finally, banana peel enzyme extract is evaluated to assess the possibility of the novelty-developed discharge agent which proves its efficiency as a potential source of oxidative enzymes that give multi-color halftones as a discharge result on naturally dyed materials. |
