Determination of acetaldehyde-semicarbazone complex as the final product of the ADHa. (A) UV/vis spectra of the formation of acetaldehyde-semicarbazone complex at 223 nm. Spectra was recorded at three min intervals; (B) Determination of the acetaldehyde released during the reaction by the enzyme ADHa and trapped by the semicarbazide; (C) Time course of ethanol and (D) allylic alcohol oxidation by the ADHa from Ga. diazotrophicus.