Extracellular ABTS-oxidizing activity of autochthonous fungal strains from Argentina in solid medium


Mario Carlos Nazareno Saparrat, AM Margarita Bucsinszky, H Alfio Tournier, MN Cabello & AM Arambarri
Rev Iberoam Micol 2000; 17: 64-68


The screening for extracellular oxidases and peroxidases from autochthonousfilamentous fungi isolated from different substrates is an important step towardsthe detection of extracellular fungal oxidative systems. Thirty-one autochthonousfungal strains from Argentina, belonging to different ecophysiological and taxonomicgroups, were plate-screened for their ability to produce extracellular oxidoreductases.Modified Kirk solid medium containing the chromogen2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) was used todetermine the presence of this extracellular activity. The fungi tested were groupedaccording to the colour intensity of the modified Kirk medium in: a) specieswithout extracellular ABTS-oxidizing activity; b) species with low extracellularABTS-oxidizing activity; c) species with moderate extracellular ABTS-oxidizingactivity; d) species with high extracellular ABTS-oxidizing activity. The assayrevealed extracellular ABTS-oxidizing activity in 90% of the strains tested. Allspecies of Basidiomycetesused exhibited ABTS-oxidizing activity, exceptLaeticorticium roseum. Aspergillus terreusand Epicoccum purpurascens( Deuteromycetes) did not show extracellular oxidative activity on ABTS.Agrocybe aegerita, Amauroderma boleticeum, Cladosporium cladosporioides,Coriolopsis rigida, Grammothele subargentea, Graphium putredinis, Hexagonahydnoides, Hexagona papyraceae, Loweporus lividus, Peniophora albobadia,Phellinus everhartii, Phellinus gilvus; Phellinus linteus; Pleurotuslaciniatocrenatus, Pycnoporus sanguineus, Rigidoporus ulmarius, Steccherinumrawakense, Talaromyces helicus, Trametes elegans, Trametes pavonia,Trametes villosa and Trichaptum sector are reported here for the first time asspecies capable of producing ABTS-oxidizing extracellular oxidorreductases.