Adapted feeding strategies in fed-batch fermentation improve sugar delivery and ethanol productivity

Figures & data

Table 1. Lignocellulosic ethanol production via simultaneous saccharification and fermentation using Saccharomyces cerevisiae.

Feedstock	Mode	Ethanol concentration (g/L)	Ethanol productivity (g/L/h)	Reference
Agro-industrial wastes	Batch	30.0	3.0	[10]
Banana peels	Batch	28.2	2.3	[11]
Barley straw	Fed-batch	51.7	0.54	[12]
Cassava pulp	Batch	27.4	0.37	[13]
Green coconut fiber	Batch	7.9	-	[14]
Rice straw	Batch	25.2	1.05	[15]
Sugarcane bagasse	Fed-batch	75.6	0.63	[16]
Spruce	Fed-batch	40.0	0.42	[17]
Pomegranate peel	Batch	12.9	0.54	[18]
Potato peel wastes	Batch	22.5	1.51	[19]

-: not indicated.

Figure 1. Changes in cell dry weight (a-d), glucose content (e-h), ethanol titer (i-l), and evolved gas flow rate (m-p) from 5% fixed (circle), 10% fixed (triangle), linear adapted (square), and exponential adapted (diamond) feeding strategies.

Table 2. Overall performance in ethanol fermentation by four feeding strategies.

Modes	Glucose consumption (g/L)	Glucose consumption rate (g/L/h)	Ethanol production (g/L)	Final ethanol concentration (g/L)	Ethanol yield (%)*	Ethanol productivity (g/L/h)
5% fixed	241$\pm$5^B	1.6$\pm$0.1^B	114$\pm$2^B	95$\pm$2^B	92$\pm$3^A	0.74$\pm$0.04^B
10% fixed	245$\pm$4^B	1.51$\pm$0.07^B	114$\pm$3^B	98$\pm$2^AB	92$\pm$2^A	0.71$\pm$0.04^B
Linear adapted	250$\pm$10^B	1.9$\pm$0.1^A	113$\pm$3^B	95$\pm$3^B	91$\pm$4^A	0.88$\pm$0.04^A
Exponential adapted	279$\pm$7^A	1.9$\pm$0.2^A	127$\pm$5^A	104$\pm$3^A	89$\pm$2^A	0.87$\pm$0.06^A

Values are expressed as mean ± standard deviation (n = 3).

*Ethanol yield (%) = Produced ethanol (g/L)/[Consumed glucose (g/L)*0.511]*100.

^aDifferent superscript letters in the same column indicate significant differences (p < 0.05) based on statistical analyses performed through Tukey HSD test.

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Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article and/or its supplementary materials.