The breakdown of plant lignin modifies the structure of lignocelluloses, thus making carbohydrates accessible for efficient bioconversion. White-rot fungi produce ligninolytic enzymes such as lignin peroxidase, manganese peroxidase, laccases and various peroxidases, which mineralize lignin efficiently. We review here applications of ligninolytic enzymes for the delignification of lignocellulosic materials, the removal of recalcitrant organic pollutants, wastewater treatment, decolorization of dyes, soil treatment, conversion of high molecular weight coal fractions to low molecular weight coal fractions, which could be used as a feed stock for the production of commodity chemicals, biopulping and biobleaching in paper industries and enzymatic polymerization in polymer industries.

Chloroperoxidase from Musa paradisiaca stem juice has been purified to homogeneity using a concentration obtained by ultrafiltration and anion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The purified enzyme gave a single protein band in SDS-PAGE analysis corresponding to molecular mass of 43 kDa. The native PAGE analysis result has also given a single protein band, confirming the purity of the enzyme. The purified enzyme was chlorinated and brominated with monochlorodimedone, the substrate used for measuring the halogenating activity of chloroperoxidases. The K m and k cat values using monochlorodimedone as the substrate were 20 μM and 1.64 s −1 , respectively, giving a k cat /K m value of 8.2 × 10 4 M −1 s −1 . The pH and temperature optima of the chlorinating activity were 3.0 and 25 • C, respectively. The K m values for the peroxidase activity using pyragallol and H 2 O 2 as the variable substrates were 89 and 120 μM, respectively. The pH and temperature optima of the peroxidase activity using pyrogalllol as the substrate were the same as the pH and temperature optima of the halogenating activity. The peroxidase activity of the enzyme is competitively inhibited by sodium azide, indicating that it is a hemeperoxidase different from nonheme peroxidases.

Lignin peroxidase from the culture filtrate of Loweporus lividus MTCC‐1178 has been purified to homogeneity using Amicon concentration and DEAE cellulose chromatography. The molecular weight of the purified lignin peroxidase using SDS‐PAGE analysis has been found to be 40 kDa. The Km values for veratryl alcohol and H2O2 for the purified enzyme were 58 and 83 μM, respectively. The calculated kcat value of the purified enzyme using veratryl alcohol as the substrate was 2.5 s−1. The pH and temperature optima of lignin peroxidase have been found to be 2.6 and 24°C, respectively.

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