Rapid Diazonium Blue B Test to Detect Basidiomycetous Yeasts

Abstract
More than 100 known eukaryotic microorganisms were examined for capacity to form red to violet pigments with diazonium blue B after alkaline hydrolysis and an ethanol wash. All 50 basidiomycetes gave rapid and unequivocal positive reactions when 1-6 day old cultures were tested, whereas all ascomycetes and algae gave negative reactions. Extracellular enzymes typical of basidiomycetous yeasts were detected in several ascomycetous taxa.