Identification of benzoquinones in pretreated lignocellulosic feedstocks and inhibitory effects on yeast

AMB Express

Table 3 Results of fermentation experiments with 2 % glucose and addition of BQ or DMBQ

Compound (g/l)	Glucose start (g/l)	Glucose at time point t (g/l)	Glucose consumed at time point t (g/l)	Y_EtOH on consumed sugar^a	BEY^b	Q ^c_EtOH	Time point t (h)
Experimental series A
BQ
0.02	19.5 ± 1.9	17.2 ± 1.7	2.4 ± 0.2	0.25 ± 0.03	0.03 ± 0.01	0.05 ± 0.01	12
0.20	19.5 ± 1.9	17.4 ± 1.7	2.2 ± 0.2	0.26 ± 0.03	0.03 ± 0.01	0.05 ± 0.01	12
1.00	19.5 ± 1.9	17.1 ± 1.7	2.5 ± 0.2	0.21 ± 0.02	0.03 ± 0.01	0.04 ± 0.01	12
DMBQ
0.02	19.5 ± 1.9	2.3 ± 0.2	17.6 ± 1.7	0.41 ± 0.04	0.36 ± 0.04	0.59 ± 0.06	12
0.20	19.5 ± 1.9	17.4 ± 1.7	2.2 ± 0.2	0.22 ± 0.02	0.02 ± 0.01	0.04 ± 0.01	12
1.00	19.5 ± 1.9	16.2 ± 1.6	3.4 ± 0.3	0.13 ± 0.01	0.02 ± 0.01	0.04 ± 0.01	12
Reference	19.5 ± 1.9	2.7 ± 0.3	17.3 ± 1.7	0.50 ± 0.05	0.43 ± 0.04	0.70 ± 0.07	12
Experimental series B
BQ
0.002	19.5 ± 1.9	2.7 ± 0.3	16.9 ± 1.7	0.50 ± 0.05	0.43 ± 0.04	0.35 ± 0.04	24
0.005	19.5 ± 1.9	2.7 ± 0.3	16.9 ± 1.7	0.49 ± 0.05	0.42 ± 0.04	0.23 ± 0.02	36
0.010	19.5 ± 1.9	2.6 ± 0.3	16.9 ± 1.7	0.49 ± 0.05	0.42 ± 0.04	0.23 ± 0.02	36
0.015	19.5 ± 1.9	2.7 ± 0.3	16.9 ± 1.7	0.48 ± 0.05	0.41 ± 0.04	0.17 ± 0.02	48
0.020	19.5 ± 1.9	17.5 ± 1.8	2.1 ± 0.2	0.27 ± 0.03	0.03 ± 0.01	0.03 ± 0.00	48
Reference	19.5 ± 1.9	1.5 ± 0.2	18.0 ± 1.8	0.50 ± 0.05	0.46 ± 0.05	0.75 ± 0.08	12

The table shows the values at start and at a specific time point in the fermentation experiments. The relative standard deviation of the method that was used for monosaccharide and ethanol analysis was estimated to ≤10 %
^ag EtOH/g consumed glucose
^bBalanced ethanol yield; g EtOH/g glucose prior to fermentation
^cVolumetric ethanol productivity; g EtOH × l⁻¹ × h⁻¹