Microbial transformation of aliphatic aldehydes by Bacillus megaterium to 2,3-dialkylacroleins

The biotransformation of a series of aliphatic aldehydes (C ₈-C₁₂) by Bacillus megaterium isolated from strawberry leaf surfaces was investigated. Products were isolated by liquid/liquid extraction and analyzed by gas chromatography (GC) combined with mass spectrometry (MS). In addition to aliphatic alcohols and the remaining aldehydes, major transformation products included the corresponding acids as well as 2,3-dialkylacroleins, dehydrated aldol addition products, which were detected for the first time as biotransformation products. To verify the structures, 2,3-dialkylacroleins were chemically synthesized from the appropriate aldehydes by base-catalyzed aldol condensation reactions and characterized by ¹H and ¹³C NMR spectroscopy. Time-course studies showed that the maximum yield of the acrolein derivatives was obtained after 6 days of incubation.