Evaluation of phytoremediation potential of Tagetes patula L. for the degradation of textile dye Reactive Blue 160 and assessment of the toxicity of degraded metabolites by cytogenotoxicity

Tagetes patula is an annual flowering plant belonging to family Asteraceae. The present study deals with in vitro decolorization and remediation of a textile dye Reactive Blue 160 by T. patula. There was considerable (∼90%) decolorization of the dye within 4 d of incubation, as confirmed by UV-vis, HPLC and FTIR analysis. The enzymes responsible for the remediation were lignin peroxidase, tyrosinase, laccase and NADH-DCIP reductase which were found in root tissues of the plantlets. GC-MS analysis of the products revealed formation of six metabolites such as sodium benzenesulfonate, 6-chloro 1,3,5-triazine-2,4-diamine, disodium benzene-1,4-disulfonate, sodium 3-amino-4-hydroxybenzenesulfonate, 1-phenylmethanediamine and sodium 4-amino-3-carboxybenzenesulfonate after phytoremediation of Reactive Blue 160. Based on the FTIR and GC-MS results, the possible pathway for the biodegradation of Reactive Blue 160 has been traced. The non-toxic nature of the degraded products was confirmed by performing cytogenotoxicity tests on root tip cells of growing Allium cepa.