Characterization of microbial species in a regenerative bio-filter system for volatile organic compound removal

Effective removal of volatile organic compounds is critical for indoor air quality control. The performance of traditional technologies of volatile organic compound removal is limited by inadequate selection of filter media, poor airflow management inside the cleaning devices, insufficient catalytic reaction surface area, and poor distribution of UV light irradiation. In comparison, the relatively new regenerative air filtration systems use a plant root bed of activated carbon, porous shale pebbles, microbes, and a wet scrubber to remove volatile organic compounds and radon from the air in tightly sealed buildings. To better understand such systems and optimize their performance, the microbes were characterized in a model bio-filter system and their activities in formaldehyde removal were isolated. Golden Pothos was chosen as the model plant, and the microbes from the plant roots and pebbles. By using universal primers to amplify 16S rRNA genes, seven different strains of bacteria were identified belonging to the species of Arthrobacter aurescens, A. oxydans, Leifsonia xyli, Pseudomonas putida, and Bacillus sp., including B. cereus. In particular, a strain of A. aurescens TC1 isolated from this system was found to remove 86.2% of formaldehyde within 24 h with a starting concentration of 11.84 ppm. These results are helpful for better understanding symbiotic microbe-plant interactions and for designing more efficient bio-filters.