Production of manganese peroxidase by white rot fungi from potato-processing wastewater: Role of amino acids on biosynthesis

Abstract

The production of manganese peroxidase (MnP) by white rot fungus strain L-25 was carried out using potato-processing wastewater and the effects of amino acids in the potato-processing wastewater was investigated. The MnP was efficiently produced from the wastewater by the addition of glucose and the maximum MnP activity linearly increased with an increase in the glucose concentration. The initial pH affected the cell growth and also the production rate of the MnP. The maximum activity and the
production rate of the MnP using the potato-processing wastewater-based medium were higher (ca. 2.5- fold) than that of the basal medium. Moreover, amino acids in the wastewater had significant effects on
the MnP production. L-Glutamic acid, L-aspartic acid and L-serine induced the MnP secretion, on the other hand, L-phenylalanine, L-tyrosine, L-leucine and L-lysine inhibited it. The addition of L-leucine and L-lysine caused growth inhibition, while, L-phenylalanine and L-tyrosine blocked the MnP biosynthetic pathway. Ammonium ion released from the L-phenylalanine by the L-phenylalanine ammonia-lyase participated in the repression of the MnP biosynthetic pathway of the strain L-25.