Abstract:The aim of this study was to obtain new Penicillium simplicissimum mutants with high yield of ligninolytic enzymes. UV induced mutagenesis of protoplast was performed on original strain Penicillium simplicissimum (Oudem.) Thom BGA. Two genetically stable mutant strains J12 and J18 were selected from a large amount of the regenerative mutants. The highest laccase and manganese peroxidase (Mnp) activities produced by strain J12 were 1.45 and 0.47-fold higher than that by original strain, reached 44.0 U/g and 50. 9 U/g, respectively. The highest lignin peroxidase (LiP) activity of 67.1 U/g was obtained by strain J18, which was 0.4-fold increased compared with its original strain. The highest degradation rate of lignin also was obtained by strain J18, which increased 1.98-fold compared with its original strain. Further experiment confirmed after seven generations successively propagating the activity of strain J12 and strain J18 were stable and did not decrease generally.