The highest interfacial biomass was detected in UHSD during simulated storage.
Firmicutes, Bacteroidetes, Actinobacteria and Ascomycota were the most abundant phyla.
Bacterial diversity is inversely proportional to the sulfur content in diesel fuel.
NMR spectroscopy revealed higher branching in the hydrocarbon chains of ULSD.
Reduction of sulfur in diesel fuel per se do not increase microbial contamination.