Metabolic engineering strategies for optimizing acetate reduction, ethanol yield and osmotolerance in Saccharomyces cerevisiae

Table 4 Specific growth rates (μ), yields (Y) of biomass, ethanol and glycerol on glucose and stoichiometric relationships between glycerol production and biomass formation, acetate consumption and glucose consumption, and acetate consumption and biomass formation in anaerobic bioreactor batch cultures of S. cerevisiae strains with different genetic modifications in glycerol and acetate metabolism

Strain	IMX992	IMX884	IMX776	IMX901
Relevant genotype	GPD1 GPD2 sga1::eutE	GPD1 gpd2::eutE	gpd1::gpsA gpd2::eutE	gpd1::gpsA gpd2::eutE ald6Δ
μ (h⁻¹)	0.28 ± 0.02	0.27 ± 0.00	0.14 ± 0.00	0.12 ± 0.02
Y biomass/glucose (g g⁻¹)	0.087 ± 0.001	0.085 ± 0.000	0.089 ± 0.000	0.077 ± 0.013
Y ethanol/glucose (g g⁻¹)	0.43 ± 0.01	0.42 ± 0.02	0.47 ± 0.01	0.49 ± 0.00
Y glycerol/glucose (g g⁻¹)	0.07 ± 0.00	0.05 ± 0.00	0.02 ± 0.00	<0.001
Glycerol produced/biomass [mmol (g biomass)⁻¹]	8.76 ± 0.25	6.34 ± 0.26	3.29 ± 0.41	<0.1
Acetate consumed/biomass [mmol (g biomass)⁻¹]	2.67 ± 0.96	2.98 ± 0.08	2.88 ± 0.17	5.71 ± 0.15
Acetate consumed/glucose (g g⁻¹)	0.011 ± 0.001	0.015 ± 0.000	0.016 ± 0.000	0.027 ± 0.003

Cultures were grown on synthetic medium containing 180 g L⁻¹ glucose and 3 g L⁻¹ acetic acid (pH 5). Specific growth rates and stoichiometries were calculated from the mid-exponential growth phase and represent averages ± mean deviations of data obtained from independent duplicate cultures

ISSN: 2731-3654