Bioaerosol diversity in waste sorting plant : feasibility and uncertainly measurement

Waste sorting activities are source of occupational bioaerosol exposure that was associated with several health disorders such as rhinitis, asthma and hypersensitivity pneumonitis. So far, the microbial biodiversity data published in this occupational environment were obtained by cultivation of microorganisms on nutrient media prior to identification.
Due to the well-known limits of cultural methods, these biodiversity measurements underestimate the real microbial taxon richness. The first aim of the study was to evaluate the suitability of high-throughput sequencing for the assessment of bioaerosol biodiversity in a waste sorting plant (WSP). The second one was to calculate the uncertainty of the global measurement process.
Bioaerosol biodiversity was assessed in a French WSP. In one cabin, three stationary parallel samples were collected by filtration of the air through polycarbonate membrane (0.8 ìm) using closed-face cassette (Milipore, France), at 10 L/min and for five hours. After DNA extraction, eukaryotic rDNA 18S and bacterial rDNA 16S were sequenced by an external provider (INRA Transfert, France). Bioinformatic sequences analysis was performed using two pipelines developed by INRA Transfert using Mothur software (Schloss and Westcott, 2009). To evaluate uncertainty of measurement process, the results of bacterial biodiversity were compared and statistical parameters were calculated. Bioaerosols were dominated by four main phyla: Firmicutes, Actinobacteria, Bacteroidetes, and Proteobacteria. The ten dominant fungal OTU (Operational Taxonomic Unit) in sorting cabin samples represented 95% of eukaryotic sequences with a predominance of Penicillium genera. The study shows that high-throughput sequencing is a suitable method for the assessment of bioaerosol biodiversity emitted in WSPs. The calculation of uncertainty allowed discriminating bioaerosols sampled in different situations and gave information about the repeatability of biodiversity measurements. These results provide the first record about biodiversity in bioaerosols from WSPs using high-throughput sequencing and an original method for uncertainty calculation from the subsequent data.