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

Table 2 Growth, glucose and xylose utilization, and ethanol yield by Z. mobilis 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	0.19 ± 0.01	0.18 ± 0.01	0.19 ± 0.01	0.19 ± 0.01
Exponential glucose uptake rate^a	12.6 ± 0.8	12 ± 1	13.0 ± 0.5	12 ± 1
Stationary xylose uptake rate^b	1.1 ± 0.1	1.2 ± 0.1	1.4 ± 0.2	1.1 ± 0.1
Total xylose consumed (mM)^c	158 ± 12	146 ± 8	172 ± 2	166 ± 4
Total ethanol produced (mM)^c	850 ± 23	810 ± 22	833 ± 21	819 ± 23
Ethanol yield (%)^d	82 ± 1	81 ± 1	81 ± 1	83 ± 2

Each value is from at least three biological replicates in different bioreactors
^aExponential phase is between 4 and 13 h. 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. Unit for xylose uptake rate is mM/OD₆₀₀/h
^cTotal xylose consumed and ethanol yield is calculated between 0 and 30 h. 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