Abstract :
[en] Indoor pollution around buildings and structures is creating some health and comfort concerns. Volatile organic compounds (VOCs) released by consume household products, adhesives and building materials, or combustion processes, are some of pollutants usually present in residential units and workplaces indoor air. Many VOCs, with different physical, chemical and biological properties, can be simultaneously found in mixture with other contaminants [1]. The hazardous effect of VOCs is related to their ability to penetrate the skin and membrane mucous, potentially damaging the human organs and metabolic systems. Understanding and controlling these pollutants can help reducing the illness risks associated. In this context, regulatory emission limits of the contaminating-compounds are nowadays taking place, mainly in Europe.
Formaldehyde (FA) is one of the most representative oxygenated-VOCs, and a widespread chemical pollutant of water, air and soil. FA is used in different industries and consumer products. Up to 65% of global FA is used to synthetize resins such as urea-FA, phenol-FA, and melamine-FA, widely used in construction materials, wood processing, furniture, textiles, carpeting, and chemical industries. This toxic compound can easily react with other macromolecules in different biological systems and is known to have mutagenic, immunogenic, allergenic and carcinogenic effects [2]. The immediate symptoms caused by the exposure to the indoor FA can vary between irritation of the eyes, nose and throat and breathing difficulties to serious injuries at the respiratory level and chronic pulmonary obstruction, with the increase of the airborne FA concentrations and time of exposure.
The development of a selective, highly sensitive, reliable and simple method for fast and inexpensive detection and degradation of FA from the indoor air, is of great interest. Among the different commercially available solutions for the indoor air FA removal, its biological degradation through biomolecules transformation, is being more and more explored as a flexible, low-cost and efficient strategy, respecting health and environmental procedure.
Formaldehyde dehydrogenase (FDH) is an enzyme able to transform FA into other less toxic compounds, as formic acid, which is eventually oxidized to carbon dioxide and water. FDH can be synthetized by different bacteria, cyanobacteria, fungi or yeasts. Pseudomonas putida is a FDH-producing bacteria, commonly used for the biodegradation of FA [3,4]. The ability to synthetize the FDH can be improved, according to the carbon and energy sources available for cells development.
The present work is an exploratory study for evaluation of FDH production by a P. putida strain, LMG 24210, under distinct carbon and energy sources. Depending on the substrate used in the fermentation medium, distinct metabolic pathways, associated either to cells growth or FDH production, could be activated. The results suggested that, sequential fermentations where, in a first fermentation, cells growth is induced, followed by a second fermentation where, FDH production is promoted, can increase FDH activity. At the end of the process, the incorporation of these biomolecules coated in solid surfaces, can be presented as an innovative solution for FA degradation from indoor air.
[1] Guieysse B. et al. (2008), Biotechnol. Adv., 26, 398-410.
[2] Salthammer T. et al. (2010), Chem. Rev., 110.
[3] Roca A. et al. (2008), Microb. Biotechnol., 1,158-169.
[4] Fujii T. et al. (1975), Agric. Biol. Chem. 39, 2325-2330.
