The volumetric and specific activities of Streptomyces viridosporus T7A lignin peroxidase isoform ALiP-P3 were increased by formulating a novel corn-starch-based growth medium by optimizing the concentrations of starch, casein, yeast extract, CaCO3, NH4Cl, and trace metals. This medium increases cell densities by 10-fold, cell-specific ALiP-PS activity by 6-fold, and volumetric ALiP-PS activity by 60-fold compared to those obtained using a yeast-extract-based medium. The presence of increased concentrations of ALiP-P3 in the starch-based cultures was confirmed by Western blot analysis. In addition, the lignin peroxidase activity was found to be highly dependent upon the concentration of the necessary cofactor, hydrogen peroxide; using 2,4-dichlorophenol as the substrate, ALiP-P3 activity increased 1448-fold as the concentration of H2O2 was varied from 0.1 to 250 mM.
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