Roles of manganese and organic acid chelators in regulating lignin degradation and biosynthesis of peroxidases by Phanerochaete chrysosporium

Abstract

We studied the effect of manganese and various organic chelators on the distribution, depolymerization, and mineralization of synthetic '4C-labeled lignins (DHP) in cultures of Phanerochaete chrysosporium. In the presence of high levels of manganese [Mn(II) or Mn(III)], along with a suitable chelator, lignin peroxidase (LiP) production was repressed and manganese peroxidase (MnP) production was stimulated. Even though partial lignin depolymerization was observed under these conditions, further depolymerization of the polymer to smaller compounds was more efficient when low levels of manganese were present. LiPs were prevalent under these latter conditions, but MnPs were also present. Mineralization was more efficient with low manganese. These studies indicate that MnP performs the initial steps of DHP depolymerization but that LiP is necessary for further degradation of the polymer to lower-molecular-weight products and mineralization. We also conclude that a soluble Mn(II)-Mn(III) organic acid complex is necessary to repress LiP.

The effect of manganese on the production of Phanerochaete flavido-alba ligninolytic peroxidases in nitrogen limited cultures

“…3E). In analogous chromatographic conditions in P. chrysosporium [15,20] and Bjerkandera spp. [17] cultures, LiP peaks exhibiting lower retention time than those showing MnP activity has been described.…”

Aryl alcohols in the physiology of ligninolytic fungi

“…The enzyme is produced as a set of closely related isozymes with molecular masses weights ranging from 38 to 43 kDa, and is encoded by different genes in P. chrysosporium [139,150], P. radiata [121,151], B. adusta [152] and T. c'ersicolor [129,153]. The expression of LiP genes is regulated by an inverse function of the Mn ~ concentration [114,154,155]. The Mn n concentration has no influence on the amount of veratryl alcohol biosynthesized [156].…”

“…The enzyme exists as several closely related isozymes and are encoded by several different genes in P. chrysosporium [159,168] and T. t,ersicolor [129,153]. The expression of MnP genes 161 is regulated by a direct function of the Mn n concentration [109,114,[154][155][156]169]. Intracellularly, the concentrations of cAMP regulate the MnP gene expression at the level of transcription [157].…”

Lignin-modifying enzymes from selected white-rot fungi: production and role from in lignin degradation

“…In addition, the roles of regulatory factors such as Mn are not adequately understood. Mn deposits have been found in white-rotted wood attacked by many fungi [1,2] and Mn in culture medium plays a regulative role in lignin degradation and in the expression of MnPs, LiPs and laccase [5][6][7].…”