Central composite experimental design in the optimization of lignin peroxidase production in shake cultures by free and immobilized Phanerochaete chrysosporium

Abstract

An orthogonal 2³-factorial experimental design was employed in the multivariate optimization of lignin peroxidase production by Phanerochaete chrysosporium in shake cultures both as free pellets and as immobilized on nylon-web, and to provide knowledge on the process for scale-up and control. It was observed that a short starving period after the growth of the mycelium and the depletion of the initial carbon source, followed by the addition of glucose to about 1 g/dm³ level together with the activator markedly enhanced lignin peroxidase production. The optimum concentration of veratryl alcohol as an activator, 2.5 mM with the immobilized fungus system was about double of that with free pellets, and about 6 to 10 times that most often previously employed. Benzyl alcohol could also be used as an activator at an optimal level of about 5.2 mM, although the lignin peroxidase activities obtained were somewhat lower than those with veratryl alcohol. The immobilization appeared to stabilize P. chrysosporium against shear effects, and in the presence of the surfactant Tween 80 in particular high lignin peroxidase activities were obtained already one to two days after the activation.