Solid State production of manganese peroxidases using arecanut husk as substrate

ABSTRACT

The lignocellulosic biomass from arecanut husk (Areca catechu Linnaeus) was evaluated as a new substrate for cultivation of Phanerochaete chrysosporium and Phanerochaete sp for solid state fermentation of manganese peroxidase (MnP). Arecanut had a moisture content of 79.84 percent for ripe nut husk whereas green nut husk had 68.39 percent moisture and a pH of 5.0, 3.0 and 7.0 for raw, ripe and dry husk. Reducing sugar content was 14.31, 19.21 and 1.77(mg/g of husk) for raw, ripe and dry nut husk, respectively. Non reducing sugar was 1.04(mg/g of husk) for raw and 0.68 (mg/g of husk) for dry husk. Solid state fermentation carried out at different pH showed optimum enzyme production at pH 6.0 (52.60 IU/g) for P.chrysosporium and pH 5.0 (44.08 IU/g) for Phanerochaete sp. Optimum temperature was 30 ± 2º C for both the organisms. Lower concentration of MnSO4 (0.1 mM MnSO4) induced maximum enzyme production in P.chrysosporium whereas Phanerochaete sp. required 1 mM MnSO4 for induction. Absence of carbon and nitrogen stimulated enzyme production in P.chrysosporium while Phanerochaete sp. needed nitrogen. Enzyme was partially purified by ammonium sulphate precipitation followed by ion exchange chromatography.