Aims: To isolate, identify and assess valienamine production by a soil bacterial isolate from a wheat field in Hangzhou, China. Methods and Results: A validamycin A-degrading bacterial strain, numbered ZJB-041, was isolated and identified as Stenotrophomonas maltophilia, based on morphology, physiological tests, ATB system (ID32 GN), and 16S rDNA analysis. The strain was capable of producing valienamine by decomposing validamycin A. After fermentation in shaking flasks at 30 degrees C for 7 days, 96.0% of 34.49 mmol l(-1) of validamycin A was degraded and 2.65 mmol l(-1) of valienamine was obtained. The resting cells of this strain also produced valienamine by degrading validamycin A. After 72 h of incubation in 0.2 mol l(-1) of phosphate buffer (pH 7.5), 90.2% of 17.16 mmol l(-1) of validamycin A was degraded, and 1.77 mmol l(-1) of valienamine was obtained. Conclusions: Our data suggested that S. maltophilia ZJB-041, a bacterial isolate, has the potential for validamycin A degradation and valienamine production. Significance and Impact of the Study: The validamycin A-degrading bacterium could potentially be utilized in the disposal of validamycin residues and in the production of valienamine.