Pycnoporus cinnabarinus lac1 gene was expressed in Yarrowia lipolytica. Different secretion signals and culture media were tested. Production was correlated to both culture growth rate and cell morphology (highest at low growth rate, without mycelium). Recombinant laccase was characterized (immunodetection, N-terminal sequencing) and purified. Production was estimated to 20 mg l(-1) in a bioreactor. Thus, complex metalloenzymes can be produced in Yarrowia, assuming some control of host physiology. Lac1p production was compared in Yarrowia, Pichia and Aspergillus: recombinant proteins were active, but host systems differed in transformation efficiency, production, and glycosylation. If not the best producer, Yarrowia offers very high transformation efficiencies, allowing the genetic engineering of laccases for industrial applications. (c) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.