Valienamine, an aminocyclitol, is an important medicinal intermediate with broad use in the synthesis of some stronger a-glucosidase inhibitors. The bacterial strain Stenotrophomonas maltrophilia CCTCC M 204024 was recently isolated in our laboratory for production of valienamine from validamycin A. In this study, conditions were varied to investigate valienamine production using this strain. We found the optimized conditions included (1) use of validamycin A as the sole carbon source (initial concentration of 15 g L-1), (2) use of (NH4)(2)SO4 as the sole nitrogen source, (3) pH 7.0, (4) temperature range between 28 and 37 C, and (5) k(L)a of 133 h(-1). Under these optimal conditions, an average of 1.15 g L-1 valienamine was obtained after fermentation for 6 d. Fermentation in a 15-L mechanically stirred tank bioreactor containing 10 L of culture medium was also done to observe valienamine production. The concentration in culture broth reached 1.09 g L-1 after 6 d of fermentation. It is concluded that degradation of validamycin A by S. maltrophilia is a promising method to achieve an effective way to production of valienamine. (c) 2006 Elsevier Inc. All rights reserved.