Quantification and mitigation of byproduct formation by low-glycerol-producing Saccharomyces cerevisiae strains containing Calvin-cycle enzymes

Table 3 Yields of biomass, acetaldehyde, acetate and ethanol on glucose and ratio between glycerol production and biomass formation in anaerobic glucose-limited chemostat cultures of S. cerevisiae strains carrying different genetic modifications at a dilution rate of 0.05 h⁻¹

Strain	IME324	IMX1489	IMX2736	IMX2701	IMX2593	IMX2608
Relevant genotype	GPD2	Δgpd2 pDAN1-prk 15 × cbbm	Δgpd2 pDAN1-prk 2 × cbbm	Δgpd2 pDAN1-prk-PEST 2 × cbbm	Δgpd2 pDAN1-prk-19aa 2 × cbbm	Δgpd2 pANB1-prk 2 × cbbm
Biomass/glucose (g_x/g)	0.084 ± 0.002	0.078 ± 0.001	0.088 ± 0.002	0.085 ± 0.000	0.089 ± 0.002	0.090 ± 0.000
Ethanol/glucose (mol/mol)	1.539 ± 0.010	1.585 ± 0.010	1.648 ± 0.005	1.549 ± 0.004	1.651 ± 0.034	1.626 ± 0.002
Acetaldehyde/glucose (mol/mol)	0.001 ± 0.000	0.056 ± 0.002	0.018 ± 0.002	0.000 ± 0.000	0.004 ± 0.000	0.012 ± 0.002
Acetate/glucose (mol/mol)	0.002 ± 0.000	0.045 ± 0.001	0.032 ± 0.002	0.000 ± 0.000	0.018 ± 0.000	0.027 ± 0.000
Glycerol/glucose (mol/mol)	0.108 ± 0.001	0.004 ± 0.000	0.005 ± 0.000	0.086 ± 0.006	0.006 ± 0.002	0.003 ± 0.000
Glycerol/biomass (mmol/g_x)	7.10 ± 0.10	0.25 ± 0.00	0.31 ± 0.01	5.60 ± 0.41	0.39 ± 0.14	0.21 ± 0.01
Electron recovery (%)	95–95	95–95	97–98	95–95	95–97	96–96

Values represent averages ± mean deviations of measurements on independent steady-state duplicate cultures. Electron recoveries were calculated as balances of degree of reduction of substrates and products [21]

ISSN: 2731-3654