ENHANCED PRODUCTION OF LIGNIN PEROXIDASE AND MANGANESE PEROXIDASE BY PHANEROCHAETE CHRYSOSPORIUM IN A SUBMERGED CULTURE FERMENTATION AND THEIR APPLICATION IN DECOLOURISATION OF DYES by CHAI CHU CHIA

The main problem when treating industrial wastewater is the removal of dyes. Some of the physical and chemical treatment techniques were effective but they might result in the production of toxic by-products and could also be the cause of a secondary pollution problem due to excessive chemical use. In order to overcome the drawbacks, the present work has focused on the biodegradation of dyes using lignin peroxidase (LiP) and manganese peroxidase (MnP) by Phanerochaete chrysosporium. The study was started with the optimization of enzymes production in the laboratory scale of submerged system. In the study of producing MnP only, the optimization of some governing parameters resulted in an increment of MnP about 175%. The optimal yield of MnP (3.00 mU/ml) was found to be produced under the conditions of 0.2% (w/v) of D-xylose, 0.4% (w/v) yeast extract, 2.0 mM ammonium dihydrogenphosphate, 1.0 mM of MnSO4, 1.0% (v/v) of 6x10 spore/ml as inoculum, initial pH of 4.0, cultivation temperature at room temperature (28 ± 2 C) and agitation speed at 100 rpm. On the other hand, in the study for optimization of LiP production only, there was an increment about 183%, and the optimal yield of LiP (4.30 mU/ml) was produced under the conditions of 0.1% (w/v) of sucrose, 0.6% (w/v) yeast extract, 2.0 mM ammonium dihydrogenphosphate, 0.4 mM of veratryl alcohol, 1.0% (v/v) of 6x10 spore/ml as inoculum, initial pH of 4.5, cultivation temperature at room temperature (28 ± 2 C) and agitation speed at 150 rpm. In the study of optimizing MnP and LiP in combination, the optimal yield of MnP (4.64 mU/ml) and LiP (5.37 mU/ml) resulted in an increment approximately 744% and 253%, respectively, and the optimized conditions were 0.1% (w/v) of D-glucose, 0.6% (w/v) yeast extract, 2.0 mM ammonium dihydrogenphosphate,