Exploring grape marc as trove for new thermotolerant and inhibitor-tolerant Saccharomyces cerevisiae strains for second-generation bioethanol production

Table 4 Effects of synthetic inhibitor cocktails and sugarcane hydrolysate formulations supplied at different concentrations on the fermentation performance at 30°C of the newly isolated S. cerevisiae strain, Fm17, and the benchmark S. cerevisiae strain, 27P, when incubated in the presence of 100 g/l glucose and 50 g/l xylose ^a

Strain	Inhibitor cocktail^b	Highest ethanol concentration, g/l	Y_E/G, g/g	Q_48h, g/l/h	q_48h, g/g/h	Y_X/G, g/g	Glucose consumption rate at 48 h, g/l/h
Fm17	None	49.4	0.49 (97%)	0.88	0.34	0.027	1.73
	A	48.6	0.49 (95%)	1.01	0.31	0.030	2.07
	B	47.9	0.48 (94%)	1.00	0.30	0.031	2.06
	C	47.1	0.47 (92%)	0.87	0.31	0.030	1.89
	D	19.0	0.46 (90%)	0.07	0.11	0.009	0.24
27P	None	48.9	0.49 (95%)	0.88	0.29	0.026	1.68
	A	48.3	0.48 (95%)	1.02	0.30	0.029	2.07
	B	46.7	0.47 (92%)	0.97	0.31	0.029	2.04
	C	45.0	0.45 (88%)	0.43	0.22	0.027	0.92
	D	0.3	0.29 (58%)	0.01	0.02	0.003	0.02
Fm17	0% SH	48.8	0.49 (96%)	0.93^c	ND	ND	2.24^c
	25% SH	47.6	0.47 (92%)	1.02^c	ND	ND	2.38^c
	50% SH	43.4	0.45 (89%)	0.70^c	ND	ND	1.76^c
	75% SH	18.6	0.42 (82%)	0.22^c	ND	ND	0.53^c
	100% SH	–	–	–	–	–	–
27P	0% SH	47.7	0.48 (94%)	0.95^c	ND	ND	2.28^c
	25% SH	44.0	0.44 (86%)	1.04^c	ND	ND	2.38^c
	50% SH	40.6	0.42 (83%)	0.46^c	ND	ND	1.12^c
	75% SH	2.4	0.24 (46%)	0.03^c	ND	ND	0.19^c
	100% SH	–	–	–	–	–	–

ND, not determined; Q_48h, volumetric productivity after 48 h; q_48h, specific productivity after 48 h; SH, sugarcane hydrolysate; Y_E/G, ethanol yield per gram of consumed glucose calculated on the basis of the highest ethanol production (the percentage of theoretical maximum is indicated in brackets); Y_X/G, biomass yield after 72 hours on initial glucose.
^aAll experiments were conducted in triplicate. Any standard deviations that were always less than 5% are not reported.
^bThe combination of 100 g/l glucose and 50 g/l xylose was used to supplement YNB broth without inhibitors (reported in the table as ‘none’ or ‘0% SH’).
^cParameter determined after 42 hours.

ISSN: 2731-3654