Controlling microbial contamination during hydrolysis of AFEX-pretreated corn stover and switchgrass: effects on hydrolysate composition, microbial response and fermentation

Table 3 Growth, glucose and xylose utilization, and ethanol yield by S. cerevisiae when grown in ACSH and ASGH produced by autoclaved (AC) or no-autoclaved (NAC) methods

	Hydrolysates
	AC-ACSH	NAC-ACSH	AC-ASGH	NAC-ASGH
Exponential growth rate^a	0.17 ± 0.01	0.16 ± 0.01	0.10 ± 0.01	0.10 ± 0.01
Exponential glucose uptake rate^a	13.8 ± 0.7	13.5 ± 0.2	17 ± 2	16 ± 1
Stationary xylose uptake rate^b	1.2 ± 0.3	1.4 ± 0.2	1.1 ± 0.1	1.0 ± 0.2
Total xylose consumed (mM)^c	145 ± 7	140 ± 17	90 ± 14	92 ± 21
Total ethanol produced (mM)^c	790 ± 30	760 ± 20	746 ± 6	722 ± 23
Ethanol yield (%)^d	80 ± 1	78 ± 1	87 ± 3	85 ± 1

Each value is from at least three biological replicates in different bioreactors
^aExponential phase is between 4 and 13 h for ACSH and between 5 and 15 h for ASGH. Growth rate is per hour, and unit for glucose uptake rate is mM/OD₆₀₀/h
^bStationary phase when glucose is gone is between 16 and 30 h for ACSH and between 20 and 42 h for ASGH. Unit for xylose uptake rate is mM/OD₆₀₀/h
^cTotal glucose and xylose consumed and ethanol yield is calculated between 0 and 30 h for ACSH and between 0 and 42 h for ASGH. All glucose was used at this time point
^dCalculated from the total ethanol produced and the total glucose and xylose consumed, assuming 2 ethanol per glucose and 1.67 ethanol per xylose

ISSN: 2731-3654