Physiological effects of over-expressing compartment-specific components of the protein folding machinery in xylose-fermenting Saccharomyces cerevisiae

Table 2 Maximum specific growth rates and product yields in anaerobic batch fermentation of 20 g/L glucose and 50 g/L xylose in defined medium (2X YNB) using strains TMB3455, TMB3457 and TMB3459

	Glucose phase			Xylose phase
	TMB3455 (control)	TMB3457 (OSM1)	TMB3459 (OSM1 ERO1)	TMB3455 (control)	TMB3457 (OSM1)	TMB3459 (OSM1 ERO1)
μ_max (1/h)	0.29 ± 0.012	0.30 ± 0.019	0.32 ± 0.044	0.029 ± 0.002	0.018 ± 0.001	0.028 ± 0.003
Yields per substrate (mol/mol sugar)
Y _xylt/s	–	–	–	0.24 ± 0.03	0.25 ± 0.01	0.20 ± 0.02
Y _glyc/s	0.22 ± 0.02	0.20 ± 0.02	0.20 ± 0.05	0.020 ± 0.000	0.016 ± 0.002	0.012 ± 0.001
Y _ac/s	0.020 ± 0.001	0.012 ± 0.000	0.017 ± 0.005	0.019 ± 0.001	0.031 ± 0.003	0.029 ± 0.003
Y _etoh/s	1.87 ± 0.14	1.96 ± 0.21	1.96 ± 0.37	1.03 ± 0.00	1.24 ± 0.15	0.87 ± 0.00
Y _succ/s	0.003 ± 0.000	0.001 ± 0.000	0.002 ± 0.001	0.009 ± 0.000	0.007 ± 0.002	0.006 ± 0.000
Y_x/s (g/mol)	10.4 ± 0.5	10.5 ± 0.2	11.9 ± 0.9	3.8 ± 0.4	2.7 ± 0.6	3.9 ± 0.4
Yields per biomass (mmol/g CDW)
Y _xylt/x	–	–	–	63.1 ± 0.3	92.9 ± 25.8	50.3 ± 0.8
Y _glyc/x	20.2 ± 0.8	18.3 ± 0.5	16.6 ± 0.2	5.2 ± 0.6	5.8 ± 0.7	3.2 ± 0.6
Y _ac/x	2.1 ± 0.1	1.8 ± 0.1	1.8 ± 0.0	5.1 ± 0.3	11.7 ± 1.8	7.3 ± 0.0
Y _etoh/x	153 ± 8	153 ± 11	147 ± 7	271 ± 30	458 ± 53	223 ± 23
Y _succ/x	0.19 ± 0.04	0.28 ± 0.18	0.22 ± 0.04	2.5 ± 0.4	2.4 ± 0.3	1.6 ± 0.22

Values are given as mean ± standard deviation of two independent experiments. Data for strains TMB3456 and TMB3458 is reported in Additional file 2: Table S3.

ISSN: 1472-6750