Mn2+ alters peroxidase profiles and lignin degradation by the white-rot fungus Pleurotus ostreatus under different nutritional and growth conditions

Roni Cohen, Limor Persky, Zahit Hazan-Eitan, Oded Yarden, Yitzhak Hadar*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

The white-rot fungus Pleurotus ostreatus produces two types of extracellular peroxidases: manganese-dependent peroxidase (MnP) and versatile peroxidase (VP). The effect of Mn2+ on fungal growth, peroxidase activity profiles, and lignin degradation by P. ostreatus was studied in liquid culture and under solid-state fermentation conditions on perlite, the latter resembling the natural growth conditions of this fungus. The fungus was grown in either a defined asparagine-containing basidiomycete selective medium (BSM) or in a rich peptone medium (PM). Biomass production, as determined by respiration experiments in solid-state fermentation and liquid cultures and fungal growth on Petri dishes, was higher in the PM than in the BSM. Mn2+ affected biomass production only in the PM on Petri dishes. In the nonamended PM, high levels of MnP and VP activity were detected relative to the nonamended BSM. Nevertheless, a higher rate of 14C-lignin mineralization was measured in the Mn2+-amended BSM, as determined during the course of 47 d of fermentation. Mn2+ amendment of the PM increased mineralization rate to that obtained in the Mn2+-amended BSM. The enzyme activity profiles of MnP and VP were studied in the BSM using anion-exchange chromatography. In the nonamended BSM, only minute levels of MnP and VP were detected. On Mn2+ amendment, two MnP isoenzymes (B1 and B2) appeared. Isoenzyme B2 was purified and showed 100% identity with the MnP isoenzyme purified in our previous study from PM-solid-state fermentation (P6). P6 was found to be the dominant isoenzyme in terms of activity level and gene expression compared with the VP isoenzymes. Based on these results, we concluded that Mn2+ plays a key role in lignin degradation under different nutritional and growth conditions, since it is required for the production of MnP in P. ostreatus.

Original languageAmerican English
Pages (from-to)415-429
Number of pages15
JournalApplied Biochemistry and Biotechnology
Volume102-103
DOIs
StatePublished - Jul 2002

Bibliographical note

Funding Information:
We thank The Smoler Protein Center of the Israel Institute of Technology, Haifa, for the protein sequencing analysis. This work was partially supported by a grant from the European Union in the frame of INCO-DC (International Co-operation with Developing Countries, contract no. ERBIC18CT970186), and by The Israeli Ministry of Science.

Keywords

  • Lignin degradation
  • Manganese peroxidase
  • Pleurotus ostreatus
  • Solid-state fermentation
  • Versatile peroxidase

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