TABLE 3.

Percentage of ¹³C labeling on the fermentation products derived from the metabolism of [¹³C]glucose by cell suspensions of T. zilligii grown on glucose^a

Substrate	Value for product:
	Acetate			Formate
	Total amt (μmol/mg of protein)	13CH3COO− (%)	CH313COO− (%)	Total amt (μmol/mg of protein)	H13COO− (%)
[1-13C]glucoseb	0.88	15	—d	0.05	66
[2-13C]glucosec	1.21 ± 0.38	7 ± 1	15 ± 2	0.09 ± 0.05	—

^aCell suspensions were incubated with 15 mM glucose at 75°C for 2 h. Products were quantified by proton NMR using formate as a standard. Percentages of ¹³C labeling were calculated by integration of the respective resonances in the ¹H spectra. The natural abundance of ¹³C (1.1%) was subtracted. 

^bResult from a single experiment. 

^cAverage values for two independent experiments. 

^d—, not detected.