Xylose fermentation efficiency of industrial Saccharomyces cerevisiae yeast with separate or combined xylose reductase/xylitol dehydrogenase and xylose isomerase pathways

Table 1 Fermentation parameters in YPX medium at 30 °C

Strain	Xylose_i (g/L)	Xylose_f (g/L)	Ethanol_max (g/L)	Xylitol_max (g/L)	Y_et/xyl24 h (g/g)	Y_xyol/xyl24 h (g/g)	DCW (g/L)
PE-2∆GRE3
XR/XDH^a	52.9 ± 2.5	0.205 ± 0.001	13.0 ± 0.3	16.7 ± 0.1	0.189 ± 0.020	0.324 ± 0.029	11.1 ± 0.8
XR/XDH + XI^b	52.9 ± 2.5	0.235 ± 0.001	12.7 ± 0.0	14.3 ± 0.2	0.222 ± 0.012	0.346 ± 0.022	13.8 ± 2.3
XI^c	52.9 ± 2.5	0.215 ± 0.031	19.3 ± 0.4	1.19 ± 0.04	0.401 ± 0.031	0.0167 ± 0.0002	10.8 ± 0.5
CA11
XR/XDH^d	51.3 ± 2.2	0.543 ± 0.010	6.73 ± 0.19	18.2 ± 0.2	0.120 ± 0.002	0.376 ± 0.014	14.1 ± 0.5
XR/XDH + XI^e	53.6 ± 1.0	0.556 ± 0.008	13.1 ± 0.3	2.55 ± 0.14	0.232 ± 0.004	0.0287 ± 0.0002	13.1 ± 0.8
XI^f	55.0 ± 0.4	2.16 ± 0.06	11.5 ± 0.0	3.23 ± 0.05	0.230 ± 0.005	0.0261 ± 0.0008	12.1 ± 0.0

Fermentation time was 72 h. Xylose_i and Xylose_f are the xylose concentrations at the initial and final time of fermentation, respectively. Ethanol_max is the maximal ethanol concentration reached during the experimental time frame. Xylitol_max is the maximal xylitol concentration reached during the experimental time frame. Y_et/xyl24 h is the ethanol yield from xylose calculated at 24 h of fermentation. Y_xyol/xyl24 h is the xylitol yield from xylose calculated at 24 h of fermentation. DCW is the dry cell weight at final time. Xylose_f: d,f***; e,f***. Ethanol_max: a,c***; b,c***; d,e***; d,f***; e,f*. Xylitol_max: a,b**; a,c****; b,c****; d,e****; d,f****. Y_et/xyl24 h: a,c*; b,c*; d,e***; d,f***. Y_xyol/xyl24 h: a,c**; b,c**; d,e***; d,f***. DCW: b,c*

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