Abstract
In most sources of lignocellulosic materials, the presence of lignin restricts access to the carbohydrate and hence prevents degradation. In the last few years biological pretreatment of lignocellulose has become a subject of growing commercial interest because of the possibility of converting it to a food or energy source at lower cost than present extraction processes. An extracellular peroxidase involved in the degradation of lignin and lignin model compounds has recently been discovered in the basidiomycete Phanerochaete chrysosporium. The scale-up of lignin peroxidase production has been hindered by phenomena such as low yields of enzyme production and inhibition of ligninolytic enzyme synthesis in agitated cultures. In this thesis, the growth conditions for the white-rot fungus P. chrysosporium for the production of lignin peroxidase have been investigated. Various substrates for growth have been studied and the appearance of lignin peroxidase was followed. The presence of cellulolytic enzymes in the media for ligninase production has also been shown. The production of lignin peroxidase by both free and immobilized cells of P. chrysosporium under shaken conditions, in medium containing 1% glucose or 1% glucose plus different concentrations of molasses, has been described. Isolation and some studies of the RNA of the fungus have also been carried out.