Table 2.

Xylose reductase (XR) and xylitol dehydrogenase (XDH) activities in Spathaspora species, expressed in units (U) per mg protein [U (mg protein)⁻¹], after 16 h of fermentation in YPX medium under moderate and severe oxygen-limited conditions, respectively

Oxygen-limited conditions	Yeast species	Strain number	XR			XDH
			NADH	NADPH	Ratio NADH/NADPH	NAD+
Moderate	Spathaspora arborariae	UFMG-CM-Y352T	0.54 ± 0.02	0.72 ± 0.06	0.75 ± 0.07	0.57 ± 0.05
	Sp. brasiliensis	UFMG-CM-Y353T	–	0.39 ± 0.02	–	0.18 ± 0.01
	Sp. passalidarum	UFMG-CM-Y469	0.83 ± 0.12	0.46 ± 0.06	1.81 ± 0.35	0.60 ± 0.07
	Sp. roraimanensis	UFMG-CM-Y477T	–	0.64 ± 0.04	–	0.74 ± 0.02
	Sp. suhii	UFMG-CM-Y475T	–	0.51 ± 0.03	–	0.74 ± 0.04
	Sp. xylofermentans	UFMG-CM-Y478T	–	0.09 ± 0.01	–	0.12 ± 0.01
	Sp. passalidarum	CBS 10155T	2.81 ± 0.31	1.62 ± 0.17	1.74 ± 0.26	1.80 ± 0.14
Severe	Sp. arborariae	UFMG-CM-Y352T	0.33 ± 0.04	0.61 ± 0.01	0.55 ± 0.07	0.84 ± 0.07
	Sp. brasiliensis	UFMG-CM-Y353T	–	0.35 ± 0.01	–	0.60 ± 0.01
	Sp. passalidarum	UFMG-CM-Y469	1.09 ± 0.12	0.63 ± 0.14	1.72 ± 0.43	1.17 ± 0.12
	Sp. roraimanensis	UFMG-CM-Y477T	–	0.26 ± 0.03	–	0.87 ± 0.01
	Sp. suhii	UFMG-CM-Y475T	–	0.20 ± 0.01	–	0.63 ± 0.04
	Sp. xylofermentans	UFMG-CM-Y478T	–	0.27 ± 0.01	–	0.54 ± 0.01
	Sp. passalidarum	CBS 10155T	4.07 ± 0.55	2.46 ± 0.27	1.66 ± 0.29	2.19 ± 0.05