Formaldehyde Treatment Using Overexpressed Aldehyde Dehydrogenase 6 from Recombinant Saccharomyces cerevisiae

Formaldehyde is a toxic compound due to its ability to react with proteins, nucleic acids and lipids and is the primary cause of nasopharyngeal cancer and sick building syndrome (SBS). Aldehyde dehydrogenases (ALDHs) are able to oxidize aldehyde substrates and maintain cellular homeostasis by metabolic reactions in prokaryotic and eukaryotic cells. ALDHs catalyze the conversions of various aldehydes to carboxylic acids using NAD or NADP as a cofactor. In this study, we designed a method for using aldehyde dehydrogenase 6 (ALD6) from recombinant Saccharomyces cerevisiae to reduce formaldehyde. The ALD6 gene was cloned under the GAL1 promoter in pYES2 and attached to green fluorescent protein (GFP). To reduce the activity of ALD6, a dominant mutant was constructed with deleted catalytic residues. These strains were successfully transformed in Saccharomyces cerevisiae as confirmed by fluorescence microscopy. The produced enzymes isolated from each strain were used to treat formaldehyde. Formaldehyde reduction was determined via measured luminescence in Vibrio fischeri. Formaldehyde levels were lowest in enzymes from cells overexpressing ALD6. Furthermore, when the strains were exposed to formaldehyde stress, NADH levels increased for strains overexpressing ALD6 and decreased for dominant negative strains. Therefore, our results suggest that ALD6 plays a key role in formaldehyde treatment. We expect that ALD6 could be used in applications related to the removal of formaldehyde.