Study on optimal production of 3-ketovalidoxylamine A C-N lyase and glucoside 3-dehydrogenase by a newly isolated Stenotrophomonas maltrophilia

3-Ketovalidoxylamine A C-N lyase and glucoside 3-dehydrogenase (G3DH), two key enzymes for valienamine synthesis, are produced by Stenotrophomonas maltrophilia. The condition of producing 3ketovalidoxylamine A C-N lyase and G3DH was optimized. Validamycin A was showed to be suitable carbon source for C-N lyase and G3DH synthesis. Maximum C-N lyase production was achieved by adding 100 ml culture medium into a 500 ml conical flask containing 5 mg/ml validamycin A, with 12% inoculation seed volume for 22 h with a productivity of 6.26 × 10 U/mg protein. The specific G3DH activity was 0.244 U/mg protein in the same culture condition at 27 h. A 15 L fermenter containing 8 liter of medium was also used in this study. Crude enzyme reaction showed the conversion of N-pnitrophenylvalidamine was achieved to 92.8% at 3 h and the yield of p-nitroaniline was 81.3% at 3 h.