Enzymatic and chemical catalysis of xylidine ponceau 2R and evaluation of products released

Abstract Dyes especially azo dyes are used extensively as coloring agents in the manufacturing process of inks, textiles, leathers, food and pharmaceuticals. Liver, bacterial (anaerobic and aerobic) and fungal enzymes metabolized azo dyes immediately and released corresponding amines with carcinogenic character. Thus, the metabolism and release of amine products from azo compounds are of considerable interest. The present study emphases on the qualitative and quantitative analysis of products released from xylidine ponceau 2R by extra cellular protein (ECP) of Streptomyces sp. SS07, in comparison with the chemical reduction. It has been observed that both enzymatic and chemical catalysis release considerable quantities of similar type of amine compounds. The extra cellular fluid protein of 0.7852 mg/mg of ECP, on treatment with xylidine ponceau 2R, releases 2,4- xylidine, 2,6-xylidine and 2-methyl 3-amino p -quinone as products at pH 9.2 and at 37 °C for a contact period of 24 h. The clear band obtained in nondenaturing polyacrylamide gel electrophoresis showed the pure nature of the enzyme used for the reduction of dye xylidine ponceau 2R. Further, HPLC and GC–MS analysis of the reaction products after extracted with chloroform, revealed that about 5–20% increase in the quantity of amine was released by ECP.