The development of paper discs immobilized with luciferase/D-luciferin for the detection of ATP from airborne bacteria

The presence of various microbes in the air is one of the main causes of respiratory diseases or ailments affecting the health of humans and livestock. Therefore, early identification and detection of microorganisms in the air are key to preventing the risk associated with microbial infection. In this study, we prepared paper discs (diameter = 0.5 cm) immobilized with luciferase/D-luciferin and found that these discs could be used to determine the adenosine triphosphate (ATP) directly from the heat-lysates of airborne bacteria. The repetition of sequential adsorption/drying of the mixture solution (luciferase and D-luciferin) was performed using paper disc. The storage stability of the paper discs at room temperature was maintained for one month following their preparation while the storage stability of the liquid-based ATP assay not maintained even for one day. The paper discs could detect ATP extracted from aerosolized Escherichia coli (E. coli) as low as 1.17 × 103 CFU/mL in pure bacteria samples or 2.32 × 103 CFU/mL in bacteria samples containing dust (1 mg/mL). ATP evaluation using the paper discs for detection of aerosolized bacteria may reduce the detection time to be less than 7 min after sampling. Novel paper discs immobilized with luciferase/D-luciferin will be valuable for the development of fast and sensitive sensors for early detection and enumeration of airborne microorganisms without preparation of enzyme solution for ATP assay.