Characterization of Oxidoreductases, Ferrireductase, and Manganese Peroxidase, from White-Rot Fungi

Manganese peroxidases (MnP) from the white-rot fungi Phanerochaete chrysosporium catalyse the oxidation of Mn2+ to Mn3+, a strong oxidizer able to oxidize a wide variety of organic compounds. Different approaches have been used to unravel the enzymatic properties and potential applications of MnP. However, these efforts have been hampered by the limited production of native MnP by fungi. Heterologous expression of MnP has been achieved in both eukaryotic and prokaryotic expression systems, although with limited production and many disadvantages in the process. Here we described a novel molecular approach for the expression and purification of manganese peroxidase isoform 1 (MnP1) from P. chrysosporium using an E. coli-expression system. The proposed strategy involved the codon optimization and chemical synthesis of the MnP1 gene for optimised expression in the E. coli T7 shuffle host. Recombinant MnP1 (rMnP1) was expressed as a fusion protein, which was recovered from solubilised inclusion bodies. rMnP1 was purified from the fusion protein using intein-based protein purification techniques and a one-step affinity chromatography. The designated strategy allowed production of an active enzyme able to oxidize guaiacol or Mn2+.

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Characterization of an amphimull under Mediterranean evergreen oak forest (Quercus ilex): micromorphological and biodynamic descriptions

Canadian Journal of Forest Research ◽

10.1139/x07-165 ◽

2008 ◽

Vol 38 (2) ◽

pp. 268-277 ◽

Cited By ~ 12

Author(s):

Simone Tagger ◽

Claude Périssol ◽

Stéven Criquet ◽

Guy Aubert ◽

Pierre Neville ◽

...

Keyword(s):

Quercus Ilex ◽

White Rot Fungi ◽

White Rot ◽

Available Phosphorus ◽

Calcium Oxalate Crystals ◽

Litter Degradation ◽

Evergreen Oak Forest ◽

Evergreen Oak ◽

Microbiological Properties

The relationships between microorganisms and microfauna were studied in an evergreen oak ( Quercus ilex L.) forest floor located in a French Mediterranean region characterized by hot and dry summers. The soil was a brown fersialitic soil with an amphimull, i.e., a mull with a thick litter. A micromorphological study of both litter and organomineral layers was used to observe relationships between white-rot fungi and fauna, such as oribatids, millipedes, enchytraeids, and earthworms. Microbiological properties of the litter and physicochemical properties of the soil were analysed. Enchytraeids comminute the faeces of other animals, whereas earthworms form aggregates. These two opposite actions probably modify aeration and water movements in deeper layers. Brown leaves and animal faeces constitute a nutritional substrate for white-rot fungi and other animals. Inside degraded cells of rootlets and bleached leaves, fungi form calcium oxalate crystals because the absorbent complex is saturated by an excess of calcium. Enzymes such as laccases, manganese peroxidases, cellulases, or xylanases were detected in the litter at significant levels. The high activity values of phosphatases in the litter could reflect a deficiency in available phosphorus. This deficiency could partly explain a low rate of litter degradation and the presence of an OH sublayer.

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