This work aims to enhance the glucosamine production by Aspergillus sp. BCRC 31742 via the optimization of dissolved oxygen (DO) control strategy. Influence of DO levels (20, 30, 40, 50 and 60%) on the glucosamine production was investigated, and it was found that the highest specific glucosamine production rate during 0-12 h and 12-60 h was obtained at DO level of 30% and 50%, respectively. Accordingly, a two-stage DO control strategy was proposed, namely, DO was controlled at 30% during 0-12 h and 50% during 12-60 h. With this DO shifting strategy, the highest glucosamine production reached 14.37 g/L, which was 1.30 times that without DO control. Here, the developed two-stage DO control strategy may be useful for the industrial production of glucosamine, and also may be meaningful for the production of other fine chemicals by the filamentous fungi fermentation. (C) 2012 Elsevier Ltd. All rights reserved.