Enzymatic Cleanup of Formaldehyde in Aqueous Solutions

Numerous methods have been developed to address gaseous formaldehyde pollution, but most of them cannot be applied directly to eliminate the pollution of formaldehyde in aqueous solutions. Formaldehyde in aqueous solutions can be leached from formaldehyde-containing solid materials (e. g., food, wood, clothes, resins) and absorbed from gaseous formaldehyde by water. Here we developed an enzymatic cleanup technique - the reconstitution of an enzyme cocktail consisting of three coenzyme-free oxidoreductases (i. e., formaldehyde dismutase, methanol oxidase, and formate oxidase) and catalase for the complete oxidation of formaldehyde. This enzyme cocktail catalyzed the reaction of formaldehyde and ambient dioxygen into carbon dioxide (CO₂) and water, which was demonstrated by the stable isotope tracer technique. Significant levels of formaldehyde were detected from aqueous solutions leached from the squid, pomfret, fabric, and curtain in the market. When this enzyme cocktail was applied to treat the leachates of contaminated samples above, formaldehyde was eliminated with degradation ratios of up to 100 %. This enzymatic cleanup technique, featuring excellent biosafety (for example, degradable catalysts and non-immunogenicity), independence from light, high degradation ratios, and no special equipment required, could be widely used to treat contaminated food, drinking water, and formaldehyde-containing leachate.