Comparative characterization of some fungal laccases

Laccase producing fungi were isolated from environmental samples. They were identified on the basis of ITS (Internal Transcribed Spacer) sequence analysis. The laccase production of the isolates were investigated and compared with those of other strains deriving from the Szeged Microbiological Collection and from mushroom producer’s spawn. The enzyme production were examined in various (e.g. basic, mineral and inducer containing) liquid media. The pH optimum determinations for laccase activities were carried out in cell free ferment broths, at pH 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7 and 8, applying 25 mM succinate buffer. The investigations were based on ABTS [2,2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate)] substrate measurement method. The results showed that under these conditions, among the ascomycetes strains investigated the best laccase producer was a Rhizoctonia solani isolate (the SzMC 6252J strain). Among the basidiomycetes tested, the best laccase producer was a Ganoderma isolate (HM3)