The transcription factors Hsf1 and Msn2 of thermotolerant Kluyveromyces marxianus promote cell growth and ethanol fermentation of Saccharomyces cerevisiae at high temperatures

Table 2 Fermentation results to evaluate the ethanol production potential of strains harboring candidate stress-related TFs (sampling time: 24 h; initial concentration of glucose: 104.8 g/l)

	Control	KmHsf1		KmMsn2		KmSfp1		KmRpn4
	Control		Percent improvement (%)		Percent improvement (%)		Percent improvement (%)		Percent improvement (%)
Final ethanol concentration (g/l)
30 °C	41.8 ± 1.3	41.8 ± 1.4	0.2	42.0 ± 0.7	0.5	42.5 ± 0.7	1.8	42.1 ± 1.4	0.7
40 °C	35.6 ± 1.1	39.1 ± 1.3	9.6	39.2 ± 1.2	10.1	36.9 ± 1.3	3.7	36.4 ± 0.5	2.4
42 °C	25.3 ± 1.3	30.5 ± 1.2	20.4	31.0 ± 0.6	22.6	25.9 ± 1.5	2.4	25.5 ± 1.3	1.3
43 °C	18.9 ± 0.3	27.2 ± 1.4	43.6	27.6 ± 1.2	45.7	19.7 ± 1.0	4.1	16.2 ± 0.8	− 14.6
Consumed glucose (g/l)
30 °C	103.6 ± 0.9	103.7 ± 1.0	0.1	104.7 ± 0.1	1.1	104.7 ± 0.1	1.1	103.7 ± 0.4	0.2
40 °C	88.5 ± 0.7	96.7 ± 0.8	9.3	97.1 ± 0.5	9.7	90.5 ± 0.4	2.2	90.3 ± 0.7	2.0
42 °C	60.9 ± 1.6	73.3 ± 2.0	20.2	74.1 ± 1.8	21.6	63.4 ± 1.2	3.8	61.9 ± 1.6	1.6
43 °C	52.2 ± 1.4	71.1 ± 0.8	36.3	72.3 ± 0.8	38.6	52.3 ± 0.7	0.2	48.0 ± 0.9	− 8.0
Metabolic yield (g ethanol/g glucose)
30 °C	0.40	0.40	0.03	0.40	− 0.6	0.41	0.7	0.41	0.5
40 °C	0.40	0.40	0.3	0.40	0.4	0.40	0.5	0.41	2.2
42 °C	0.42	0.42	0.2	0.42	0.8	0.41	− 1.3	0.41	− 0.9
43 °C	0.36	0.38	5.3	0.38	5.1	0.38	3.9	0.34	− 7.2
Percentage of the theoretical yield: 0.51 g ethanol/g glucose (%)
30 °C	79.1%	79.1%	0.03	78.6%	− 0.6	79.6%	0.7	79.5%	0.5
40 °C	78.8%	79.0%	0.3	79.1%	0.4	79.9%	1.4	79.1%	0.4
42 °C	81.4%	81.5%	0.2	82.1%	0.8	80.3%	− 1.3	80.7%	− 0.9
43 °C	71.1%	74.9%	5.3	74.7%	5.1	73.9%	3.9	66.0%	− 7.2

ISSN: 2731-3654