Aureobasidium pullulans HN6.2 can produce a high level of both siderophores and pullulan. However, the generation of pullulan negatively affects siderophore purification. In this study, the pullulan synthetase gene (PUL1) in the siderophore-producing A. pullulans HN6.2 was disrupted and the obtained disruptant DPS1 produced much less polysaccharide but yielded more siderophores than A. pullulans HN6.2. Additionally, the transcription level of the PUL1 gene in A. pullulans HN6.2 was much higher than that of the PUL1 gene in the disruptant DPS1. However, the transcription level of the gene encoding L-ornithine-N-5-monooxygenase in A. pullulans HN6.2 and the disruptant DPS1 was not changed. During the chemical extraction process, more siderophores were recovered in the supernatant of the disruptant DPS1 than in the supernatant of A. pullulans HN6.2. Furthermore, ethanol addition for pullulan removal could be omitted during siderophore extraction from the supernatant of the disruptant DPS1, indicating that the siderophore extraction can be simplified. (C) 2012 Elsevier Ltd. All rights reserved.