Enhanced Production Of Lignin Peroxidase And Manganese Peroxidase By Phanerochaete Chrysosporium In A Submerged Culture Fermentation And Their Application In Decolourisation Of Dyes

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Date
2008-01
Authors
Chai, Chu Chia
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Abstract
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 MnS04, 1.0% (v/v) of 6x106 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 '6x106 sporelml 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 O-glucose, 0:6% (w/v) yeast extract, 2.0 mM ammonium dihydrogenphosphate, 0.4 mM of veratryl alcohol, 1.0 mM MnS04, 1.0% (v/v) of 6x106 sporelml as inoculum, initial pH of 4.5, cultivation temperature at room temperature (28 ± 2°C) and agitation speed at 150 rpm. As for the decolourisation of methylene blue, it could be occurred through two stages, which were adsorption on the fungal biomass orland enzymatic biodegradation. The medium with mixture of enzymes, in which both liP and MnP were secreted together, achieved the highest decolourisation rate (87%), followed by liP (82%) and MnP (57%) when the enzyme was produced separately. Therefore, the production of liP and MnP in combination provided the most powerful effect of decolourisation of methylene blue compared to the production of each enzyme separately.
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Biodegradation of dyes , using lignin peroxidase
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