Aviation fuel contaminants
Microbial contamination in aviation fuel systems is problematical and can lead to fouling of sensors and blocking of filters, corrosion and fuel degradation. Regular testing is required to identify microbial contamination. Test methods based on the identification of major fuel microbial contaminants require the microbiome of contaminated fuel to be characterised. The shift from fossil fuel sources to alternative fuels (synthetic fuels or sustainable aviation fuels – SAFs) brings changes in aviation fuel composition that may influence microbial community composition. This study focuses on the microbiome of alternative aviation fuels which have been proposed by the global aviation industry as means to reduce its carbon footprint, as well as providing diversification in the fuel supply chain, securing a cleaner and more sustainable future for aviation sector.  In this study we examined changes in the microbiomes of two communities when they were cultured with different fuel types (conventional kerosene, synthetic and sustainable fuel blends), as a carbon source. Microbial growth and community composition was determined by weighing the microbial biomass, and using culture-independent methods, namely quantitative RTPCR and high-throughput DNA sequencing. With these two starting communities, similar microbial growth was observed with all fuel types. Although there were numerical differences in the relative abundance of different community members, there was no major changes in community membership or in the dominant contaminants across the studied fuels. This indicates that the introduction of alternative aviation fuels did not result in significant alterations in the fuel microbiome. However, contaminating microbiomes are known to be highly diverse and this potential issue should be monitored closely by the fuel industry.