Foha Microbiol 47 (3). 283-280 (2002) http: //www .blomed. cas. cz/mbu/folia/ Decolorization of Synthetic Textile Dyes by Lignin Peroxidase of Phanerochaete chrysosporium P. VERMA, D. MADAMWAR* Post-Graduate Departmentof Btosctences. Sardar Patel Universtty, t'allabh Vidyanagar. 388 120 Gujarat, India Received 12 December2001 ABSTRACT. Neem hull waste (containing a high amount of lignin and other phenolic compounds) was used for lignin peroxidase production by Phanerochaete chrysosporum under solid-state fermentation con- ditions. Maximum decolorization achieved by partially purified lignin peroxidase was 80 % 'for Porocion Brilliant Blue HGR, 83 for Ranocid Fast Blue, 70 for Acid Red 119 and 61 for Navidol Fast Black MSRL. The effects of different concentrations of veratryl alcohol, hydrogen peroxide, enzyme and dye on the effici- ency of decolorization have been investigated. Maximum decolorization efficiency was observed at 0.2 and 0.4 mmol/L hydrogen peroxide, 2.5 mmol/L veratryl alcohol and pH 5.0 after a l-h reaction, using 50 ppm of dyes and 9.96 mkat/L of enzyme. Industrial wastewaters originating from textile mills, paper mills, distilleries, paints and color facto- ries, pig farms and tanneries pose serious water pollution due to their color contents and toxic components. These effluents can cause water-borne disorders such as nausea, hemorrhage, ulceration of skin and mucous membrane, dermatitis, perforation of nasal septum, severe irritation of respiratory tract and cancer (Shah et al. 1999), apart from being esthetically objectionable. Decotorization of industrial dyes is carried out using one or more of physico-chemical methods (see, e.g., Gabriel et al. 2000); the process is expensive which limits its application (Zheng et al. 1999). Remediation of such wastes by different microorganisms appears to be highly attractive; of the microorga- nisms studied for the decolorization various ligninolytic fungi have been considered to be.most prospective (Martens and Zadrazil 1998; Kahraman and Ye,~ilada 1999, 2000; l)as et al. 2000; Sam and Ye~ilada 2001; Unyayar et al. 2001). Production of extracellular enzymes by the lignin-degrading fungi is suitable for the degradation of mixtures of refractory substances owing to their nonspecific degradative availability (Kirk and Farrell 1987). The complex of ligninolytic enzymes includes lignin peroxidases (LIP), manganese peroxidase (MnP), and laccase (Lcc). Among a wide group of organisms producing such enzymes, the white-rot fungus Phanerochaete chrysosporium has been studied most frequently (Sani et al. 1998; Darah and Ibrahim 1998; Karl6 et aL 1998). These enzymes have also been produced by solid-state fermentation using agricultural wastes (Knapp et al. 1994; Buckley and Dobson 1998). Here we demonstrate the LiP production by P. ehryso- sporium solid-state fermentation using neem hull waste as substrate and the ability of produced enzyme to decolorize synthetic dyes. MATERIALS AND METHODS Chemicals. All chemicals used were of analytical-grade purity. The common name of all dyes has been used for convenience; the dyes were procured by local industries (Table I). Veratryl alcohol (3,4-dime- thoxybenzylalcohol) was purchased from Sigma. Neem (Azadirachta indica A. Jus) hulls were obtained from National Trees Grower Co-operative Federation Ltd (Anand, India). Microorganism. Phanerochaete chrysosporium was obtained from the Institute of Forstbotanik (G0ttingen, Germany). The culture was grown on malt-extract agar at 26 + 1 ~ and stored at 4 ~ it was subcultured once in two months. Enzyme production. Fifty g of dry powdered neem hull waste was taken in each 500-mL Erlen- meyer flask containing 100 mL medium (in g/L: KH2PO4 1, KCI 0.5, MgSO4"7H20 0.5, yeast extract 0.5; pH adjusted to 5 with 0. I mmol/L NaOH or 0.1 mol/L HCI). The flasks were inoculated with 5 x 5 mm pie- *Corresponding author.