Microbiological Contamination at Workplaces in a Combined Heat and Power (CHP) Station Processing Plant Biomass

The aim of the study was to evaluate the microbial contamination at a plant biomass processing thermal power station (CHP). We found 2.42 × 10³ CFU/m³ of bacteria and 1.37 × 10⁴ CFU/m³ of fungi in the air; 2.30 × 10⁷ CFU/g of bacteria and 4.46 × 10⁵ CFU/g of fungi in the biomass; and 1.61 × 10² CFU/cm² bacteria and 2.39 × 10¹ CFU/cm² fungi in filtering facepiece respirators (FFRs). Using culture methods, we found 8 genera of mesophilic bacteria and 7 of fungi in the air; 10 genera each of bacteria and fungi in the biomass; and 2 and 5, respectively, on the FFRs. Metagenomic analysis (Illumina MiSeq) revealed the presence of 46 bacterial and 5 fungal genera on the FFRs, including potential pathogens Candida tropicalis, Escherichia coli, Prevotella sp., Aspergillus sp., Penicillium sp.). The ability of microorganisms to create a biofilm on the FFRs was confirmed using scanning electron microscopy (SEM). We also identified secondary metabolites in the biomass and FFRs, including fumigaclavines, quinocitrinines, sterigmatocistin, and 3-nitropropionic acid, which may be toxic to humans. Due to the presence of potential pathogens and mycotoxins, the level of microbiological contamination at workplaces in CHPs should be monitored.