Biactive coatings applied for indoor air quality improvement

Indoor air pollution of residential units and workplaces is a major concern of nowadays. Toxic pollutants such as formaldehyde, which have carcinogenic effects in health, are constantly released from distinct construction and decoration materials and/or household's products [1,2]. The development of bioactive coatings incorporating biomolecules able to capture and degrade this toxic compound is of major interest. However, the conservation of their bioactivity is crucial throughout time [3]. The incorporation of whole cells in the sol-gel matrix, compared to extracted and purified enzymes, can provide an optimized environment. This allows the conservation of enzymes stability and co-factors regeneration, needed for the enzymatic conversion, besides eliminating extraction/purification costs [4].
The encapsulation of freeze-dried bacterial cells in a sol-gel matrix for formaldehyde degradation is herein studied. Cellulose paper chromatography was used as substrate to immobilize the whole cells, applied by spraying technique. Coated substrates, prepared with different sol-gel formulations, were stored at two different temperatures. Formaldehyde degradation ability and durability of the coatings were evaluated throughout storage time. In addition, coatings surface adhesion, thickness and morphology were also characterized. Results proved that bioactive coatings are a simple, cheap, and environmental friendly technology, efficient to biologically improve de quality of indoor air and even water.