| Abstract: | Biodiesel is an oxygenated biofuel, and it has unsaturated carbon chains. It is more susceptible to oxidation, and because it is more hygroscopic than diesel, an increase in microbial contamination may also be favored. To study the biodiesel/diesel mixture's storage, a commercial sample of diesel B (B7 S500; 7% v / v biodiesel in diesel) was collected in a Center Western region station (Brazil) and stored in tanks. Lab analyses were performed for 90 days, the first time point being zero, and the following time points were taken every 30 days. Chemical analysis was performed using gas chromatography using methyl nonadecanoate as standard. Analysis of variance, with a probability of 95%, indicated that at 60 days of storage, the sample already presented chemical degradation. Microbial monitoring was performed and It was possible to distinguish four bacterial genera (Alkalihalobacillus, Bacillus, Paenibacillus, and Peribacillus) and at least 15 species. Fungi were isolated, and 17 genera were identified (32 species): Aspergillus, Cladosporium, Penicillium, Chaetomium, Curvularia, Epicoccum, Microascus, Paecilomyces, Acanthophysellum, Arthrinium, Bypolaris, Paraconiothyrium, Parengyodontium, Phlebiopsis, Polyporus, Talaromyces, and Xylaria. The isolation results showed a low level of contamination of the as-received B7 blend from the fuel station, which can be considered natural microbial contamination expected in a storage tank. The present study confirmed the contamination of B7 blend storage tanks by various microorganisms that can colonize
and most likely degrade fuels and should be investigated in more detail as possible reference strains in biodeterioration studies. |
