I. sakaiensis can grow aerobically with PET as the substrate yielding CO2 as the end product , and we demonstrate here the fermentative growth of I. sakaiensis with PET as the sole carbon and energy source. The fermentation was carried out with I. sakaiensis (OD600 = 0.6) in 15 mL bicarbonate-buffered complex medium (Table ) in an anaerobic vial with PET films (60 mg) as the sole carbon source inoculated at ambient conditions (pH 7, 30 0 C). 1 H nuclear magnetic resonance ( 1 H NMR) spectroscopy using trimethylsilylpropanoic acid (TSP) as the internal standard for the quantification of the product pool revealed significant acetate production from PET after 5 d and ethanol production after 15 d of anaerobic incubation (Figure ). No other products have been identified via NMR spectroscopy (Figure ). This result suggests hydrolysis of PET into its monomers (TPA and EG), followed by fermentation of EG into acetate and ethanol. To verify this hypothesis, I. sakaiensis was directly grown on EG as the sole substrate and shown to ferment EG into acetate and ethanol (Figure and). Control experiments without I. sakaiensis and with heat-killed I. sakaiensis cells did not yield any products (Table ). Experiments in the absence of PET and EG resulted in no ethanol and minor acetate production after 30 d, which corresponds to less than 2% of total acetate produced with EG after 22 d (Table ). This formation of acetate in the absence of substrate is likely a result of carbon storage compounds inside I. sakaiensis. These control experiments confirm that both, live I. sakaiensis cells and the substrate PET or EG are required for the anaerobic conversion of PET or EG to acetate and ethanol (Table ).