Use of chemostat cultures mimicking different phases of wine fermentations as a tool for quantitative physiological analysis

Table 1 Comparison between reconciliated specific rates observed in batch and the equivalent chemostat cultures

		Culture time (h)	Specific consumption/production rates (mmols g DCW ⁻¹ h⁻¹)
		Culture time (h)	Glucose	Fructose	Ethanol	Glycerol	Acetic acid	Succinic acid	Lactic acid
*0.27 h* ⁻¹	*Corresponding batch phase*	8 – 17	−7.3 – -10.2	−2.2 – -7.7	6.2 – 22.0	1.08 – 3.16	0.07 – 0.19	0.04 – 0.26	0.04 – 0.08
*0.27 h* ⁻¹	*Chemostat steady state*	5.5 RT (1 RT = 3.7 h)	- 14.8 ± 20	- 1.2 ± 28	17.2 ± 3.6	8.3 ± 1.1	n.d.	0.09 ± 0.01	n.d.
*0.04 h* ⁻¹	*Corresponding batch phase*	20 – 35	−4.4 – -7.2	−2.2 – -3.6	11.2 – 18.6	0.67 – 1.11	0.09 – 0.15	0.03 – 0.05	0.03 – 0.04
*0.04 h* ⁻¹	*Chemostat steady state*	5.5 RT (1 RT = 25 h)	−5.0 ± 1.4	−2.3 ± 1.5	12.7 ± 1.0	0.97 ± 0.3	n.d	0.07 ± 0.01	n.d.
*0.02 h* ⁻¹	*Corresponding batch phase*	30 – 58	−2.7 – -4.8	−2.31– -3.1	7.2 – 12.8	0.4 – 0.7	0.02 – 0.1	0.02 – 0.03	0.02 – 0.06
*0.02 h* ⁻¹	*Chemostat steady state*	3 RT (1 RT = 50 h)	−3.0 ± 0.6	−1.52 ± 0.6	7.9 ± 0.6	0.70 ± 0.26	0.03 ± 0.003	0.06 ± 0.01	n.d.
*0.007 h* ⁻¹	*Corresponding batch phase*	60 – 106	0 – -2.52	−1.79 – -2.07	0.78 – 8.11	0.03 – 0.36	0 – 0.04	0.02	0.003
*0.007 h* ⁻¹	*Chemostat steady state*	3 RT (1 RT = 5.9 d)	−2.0 ± 0.3	−1.34 ± 0.3	5.92 ± 0.6	0.58 ± 0.35	n.d.	0.04 ± 0.004	n.d.

Media for chemostat ran at D = 0.04 and 0.02 h⁻¹ contained 70% of the amino acid composition of the batch medium, while medium used for D = 0.007 h⁻¹ contained 40% of the amino acid composition. For batch cultures, ranges of the specific conversion rates are given. n.d., not determined (product concentration below detection limits).

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