Effect of oxygenation and temperature on glucose-xylose fermentation in Kluyveromyces marxianus CBS712 strain

Table 1 Sugars consumption rates and ethanol production rates

T^a(°C)	O₂ ^b(%)	Volumetric consumption and production rates (gL⁻¹ h⁻¹)							Yields (gg⁻¹)
		Glucose	Xylose	Ethanol	Biomass	Glycerol	Acetate	Xylitol	Biomass	Glycerol	Acetate	Xylitol
30°C	20.95	2,23	0,21	0,77	0,08	n.d.^c	0,04	n.d.^c	0,17	0,02	0,07	n.d.^c
	11.00	2,13	0,11	0,79	0,07	0,01	0,07	n.d.^c	0,17	0,03	0,16	n.d.^c
	1.75	1,94	0,03	0,76	0,03	0,02	0,02	0,02	0,09	0,08	0,05	0,79
41°C	20.95	3,22	0,14	0,15	0,05	0,01	0,13	n.d.^c	0,10	0,03	0,26	n.d.^c
	11.00	3,16	0,15	1,18	0,05	0,01	0,11	n.d.^c	0,11	0,04	0,24	n.d.^c
	1.75	2,80	0,05	1,12	0,03	0,02	0,03	0,04	0,08	0,09	0,08	0,75

^aT, temperature.
^bO₂, inlet oxygen.
^cn.d., not detectable.
Sugar (glucose and xylose) consumption rates, production rates (biomass, ethanol, glycerol, acetate and xylitol) and yields (biomass, glycerol, acetate and xylitol) at different temperature and oxygen supply. Glucose consumption rates were calculated during the CO₂ production phase, while xylose consumption rates were calculated starting from the first point after glucose exhaustion until the last point of the fermentation. Ethanol production rates relate only to the glucose consumption phase since on xylose consumption phase, in all the tested conditions, no significant ethanol production was observed. Yields and volumetric production rates of biomass, glycerol and acetate were calculated based on the total consumed sugars, while xylitol yields and volumetric production rates were calculated based on the consumed xylose only.
The results shown are average values of three replicates where the deviation from the mean value was always less than 3%.

ISSN: 1475-2859