Active coating including microorganism for indoor formaldehyde degradation

Indoor environmental contamination of residential units and workplaces is a major problem that needs efficient, durable and environmentally friendly solutions. The development of active coatings capable of entrapping and degrading selectively pollutants such as formaldehyde is herein proposed. Freeze-dried Pseudomonas putida sp. cells were introduced in sol-gel coatings. Precursor ratio, thickness and water content of the coatings were the parameters used to optimize their effectiveness on formaldehyde degradation. Although with different abilities, bacterial cells immobilized into the distinct sol-gel formulations were able to degrade formaldehyde. The presence of 3-glycidoxypropyltrimethoxysilane and polyethylene glycol in the sol-gel promoted the enzymatic degradation of formaldehyde as they provide the stability of the humidity of the coatings and so, the well-being of the cells. Storage temperature and time proved to be important variables for keeping the enzymatic activity of degrading-microorganisms incorporated in the sol-gel coatings. Coating formulations promoting the higher abilities to degrade formaldehyde provided also good mechanical properties. (paper)