Airborne Fungal and Bacterial Components in PM1 Dust from Biofuel Plants

作者：Madsen Anne Mette^*; Schlunssen Vivi; Olsen Tina; Sigsgaard Torben; Avci Hediye

来源：Annals of Occupational Hygiene, 2009, 53(7): 749-757.

DOI：10.1093/annhyg/mep045

• actinomycetes
• aerodynamic diameter of fungi
• bacteria
• bioaerosol
• biofuel
• exposure
• inhalable dust
• PM1 dust

Fungi grown in pure cultures produce DNA- or RNA-containing particles smaller than spore size (< 1.5 mu m). High exposures to fungi and bacteria are observed at biofuel plants. Airborne cultivable bacteria are often described to be present in clusters or associated with larger particles with an aerodynamic diameter (d(ae)) of 2-8 mu m. In this study, we investigate whether airborne fungal components smaller than spore size are present in bioaerosols in working areas at biofuel plants. Furthermore, we measure the exposure to bacteria and fungal components in airborne particulate matter (PM) with a D-50 of 1 mu m (called PM1 dust). PM1 was sampled using Triplex cyclones at a working area at 14 Danish biofuel plants. Millipore cassettes were used to sample 'total dust'. The PM1 particles (29 samples) were analysed for content of 11 different components and the total dust was analysed for cultivable fungi, N-acetyl-beta-D-glucosaminidase (NAGase), and (1 -> 3)-beta-D-glucans. In the 29 PM1 samples, cultivable fungi were found in six samples and with a median concentration below detection level. Using microscopy, fungal spores were identified in 22 samples. The components NAGase and (1 -> 3)-beta-D-glucans, which are mainly associated with fungi, were present in all PM1 samples. Thermophilic actinomycetes were present in 23 of the 29 PM1 samples [average = 739 colony-forming units (CFU) m(-3)]. Cultivable and 'total bacteria' were found in average concentrations of, respectively, 249 CFU m(-3) and 1.8 x 10(5) m(-3). DNA- and RNA-containing particles of different lengths were counted by microscopy and revealed a high concentration of particles with a length of 0.5-1.5 mu m and only few particles > 1.5 mu m. The number of cultivable fungi and beta-glucan in the total dust correlated significantly with the number of DNA/RNA-containing particles with lengths of between 1.0 and 1.5 mu m, with DNA/RNA-containing particles > 1.5 mu m, and with other fungal components in PM1 dust. Airborne beta-glucan and NAGase were found in PM1 samples where no cultivable fungi were present, and beta-glucan and NAGase were found in higher concentrations per fungal spore in PM1 dust than in total dust. This indicates that fungal particles smaller than fungal spore size are present in the air at the plants. Furthermore, many bacteria, including actinomycetes, were present in PM1 dust. Only 0.2% of the bacteria in PM1 dust were cultivable.

• 出版日期2009-10