Degradation of sulfonated azo dyes by the purified lignin peroxidase from <Emphasis Type="Italic">Brevibacillus laterosporus</Emphasis> MTCC 2298

Lignin peroxidase (EC 1.11.1.14) was purified from the Brevibacillus laterosporus MTCC 2298 by ion exchange chromatography. The K_m value of the purified lignin peroxidase (using n-propanol as substrate) was 1.6 mM. The MW of purified enzyme determined with the help of MW-standard markers was approximately 205 kDa. Purity of the enzyme was confirmed by native polyacrylamide gel electrophoresis (PAGE) and the activity staining using a substrate L-DOPA. Sulfonated azo dyes such as Methyl orange and Blue-2B were degraded by the purified lignin peroxidase. Degradation of the dyes was confirmed by HPLC, GC-MS, and FTIR spectroscopy. The mainly elected products of Methyl orange were 4-substituted hexanoic acid (m/z = 207), 4-cyclohexenone lactone cation (m/z = 191), and 4-isopropanal-2, 5-cyclohexa-dienone (m/z = 149) and for Blue-2B were 4-(2-hexenoic acid)-2, 5-cyclohexa-diene-one (m/z = 207; M − 1 = 206) and dehydro-acetic acid derivative (m/z = 223).