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

Serate, Jose; Xie, Dan; Pohlmann, Edward; Donald, Charles; Shabani, Mahboubeh; Hinchman, Li; Higbee, Alan; Mcgee, Mick; La Reau, Alex; Klinger, Grace E.; Li, Sheena; Myers, Chad L.; Boone, Charles; Bates, Donna M.; Cavalier, Dave; Eilert, Dustin; Oates, Lawrence G.; Sanford, Gregg; Sato, Trey K.; Dale, Bruce; Landick, Robert; Piotrowski, Jeff; Ong, Rebecca Garlock; Zhang, Yaoping

doi:10.1186/s13068-015-0356-2

Biotechnology for Biofuels and Bioproducts

Table 1 Composition of AFEX-treated corn stover hydrolysate (ACSH) and AFEX-treated switchgrass hydrolysate (ASGH) produced by either AC or NAC method

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

Components	AC-ACSH	NAC-ACSH	AC-ASGH	NAC-ASGH
Major carbohydrates and acids (mM)
d-Glucose	355.0^a ± 5.8	357.4^a ± 8.6	328.7^b ± 4.2	343.9^ab ± 11.3
d-Xylose	211.2 ± 3.6	209.1 ± 5.6	208.0 ± 2.5	223.4 ± 10.6
Succinate	0.6 ± 0.1	0.7 ± 0.2	0.4 ± 0.1	0.6 ± 0.1
Lactate	1.4^a ± 0.1	1.6^a ± 0.4	0^b	0^b
Glycerol	5.4^a ± 0.7	5.4^a ± 0.5	3.6^b ± 0.4	4.0^b ± 0.7
Formate	2.8^bc ± 2.4	1.6^c ± 1.1	7.6^a ± 2.0	5.7^ab ± 1.5
Acetate	31.4^b ± 2.7	30.7^b ± 2.0	42.1^a ± 1.6	40.9^a ± 1.8
Acetamide	107.5 ± 13.0	107.0 ± 6.8	88.9 ± 2.5	111.6 ± 17.1
Abundant minerals and anions (mM)
P	17.4^a ± 1.0	16.6^a ± 0.4	12.5^b ± 0.9	12.0^b ± 0.4
K	39.6^b ± 1.0	39.1^b ± 2.0	52.3^a ± 1.6	53.2^a ± 2.1
Ca	4.5^a ± 0.2	4.6^a ± 0.2	0.6^b ± 0.0	0.4^b ± 0.1
Mg	11.7^b ± 0.3	11.6^b ± 0.4	14.8^a ± 0.8	15.1^a ± 0.8
S	4.3^ab ± 0.2	4.1^b ± 0.4	4.8^a ± 0.1	4.7^a ± 0.1
Na	1.7^b ± 0.0	1.6^b ± 0.1	3.0^a ± 0.1	3.0^a ± 0.1
Cl	59.3^b ± 3.6	57.3^b ± 1.0	80.6^a ± 1.1	76.4^a ± 8.7
PO₄	17.4^a ± 1.0	16.6^a ± 0.4	12.5^b ± 0.9	12.0^b ± 0.4
SO₄	4.3^ab ± 0.2	4.1^b ± 0.4	4.8^a ± 0.1	4.8^a ± 0.1
NH₄-N	49.7 ± 3.8	52.5 ± 5.5	51.2 ± 9.0	54.8 ± 7.1
Total N	252.7^a ± 6.8	252.5^a ± 3.6	226.4^b ± 8.7	219.9^b ± 10.6
Trace minerals and anions (μM)
Zn	15.6^a ± 0.6	18.4^a ± 2.0	7.1^b ± 0.2	8.2^b ± 0.8
B	19.1^a ± 2.8	5.5^Ab ± 3.4	6.8^b ± 1.1	<3.7^Ab
Mn	88.8^a ± 14.1	85.4^a ± 14.8	38.9^b ± 3.5	42.8^b ± 2.7
Fe	23.8^ab ± 3.5	31.3^a ± 2.5	16.9^b ± 2.5	17.4^b ± 3.9
Cu	2.5^a ± 0.7	2.2^a ± 0.3	0.9^b ± 0.1	1.1^b ± 0.2
Al	9.9 ± 3.6	9.8^A ± 7.2	8.8^A ± 5.4	15.1 ± 2.3
Cd	<0.1^A	<0.1^A	<0.1^A	<0.1^A
Co	<0.1^A	<0.1^A	<0.1^A	<0.1^A
Cr	4.8 ± 0.7	10.5 ± 3.5	5.4 ± 1.2	8.8 ± 3.9
Mo	0.3^a ± 0.1	0.1^Ab ± 0.0	0.4^a ± 0.1	0.1^Ab ± 0.0
Ni	2.6^ab ± 0.3	2.9^a ± 0.5	1.4^b ± 0.4	1.4^b ± 0.7
Pb	<0.2^A	<0.2^A	<0.2^A	<0.2^A
Li	0.4^A ± 0.3	0.4 ± 0.1	0.4^A ± 0.3	0.4^A ± 0.3
Br	<0.1^A	<0.1^A	<0.1^A	<0.1^A
NO₂	<0.2^A	<0.2^A	<0.2^A	<0.2^A
Lignotoxins and other inhibitors (μM)
Furfural	67.2^a ± 19.7	36.7^b ± 11.5	54.3^ab ± 2.3	32.7^b ± 4.1
Benzamide	3.1^b ± 0.3	2.6^b ± 0.2	6.6^a ± 0.8	5.9^a ± 0.3
Coumaroyl amide	3152.1^a ± 366.0	1937.6^b ± 97.3	1873.0^b ± 63.3	982.5^c ± 65.5
Feruloyl amide	1529.0^a ± 162.6	1043.7^b ± 31.8	667.3^c ± 9.4	375.2^d ± 24.6
4-Hydroxybenzamide	12.0^a ± 1.3	12.3^a ± 0.6	10.3^a ± 1.1	7.1^b ± 0.5
Syringamide	42.5^a ± 11.1	24.8^b ± 2.4	28.7^b ± 3.7	17.6^b ± 1.7
Vanillamide	125.6^a ± 12.6	61.6^bc ± 6.5	76.8^b ± 8.7	51.8^c ± 6.4
Acetovanillone	40.0^a ± 5.3	33.9^ab ± 4.6	28.8^b ± 0.6	18.2^c ± 0.5
Acetosyringone	0.2^Ab ± 0.1	0.5^Ab ± 0.4	1.8^a ± 1.0	1.2^ab ± 0.2
5-Hydroxymethylfurfural (HMF)	1.1^a ± 0.3	0.6^b ± 0.0	1.1^a ± 0.2	0.4^b ± 0.0
4-Hydroxybenzaldehyde	21.6^a ± 3.5	13.7^b ± 0.8	19.6^a ± 3.4	10.1^b ± 0.7
4-Hydroxyacetophenone	1.9^ab ± 0.6	1.0^c ± 0.2	2.3^a ± 0.5	1.2^bc ± 0.1
Syringaldehyde	7.4^a ± 1.7	1.8^b ± 0.2	5.4^a ± 1.7	0.9^b ± 0.1
Vanillin	141.5^a ± 14.5	73.8^b ± 5.0	76.6^b ± 17.8	27.5^c ± 1.3
4-Hydroxybenzyl alcohol	<0.2^Ab	0.3^Ab ± 0.3	0.5^Ab ± 0.6	1.4^a ± 0.1
Vanillyl alcohol	0.3^b ± 0.0	0.6^ab ± 0.3	0.5^ab ± 0.1	0.8^a ± 0.1
Azelaic acid	21.4 ± 0.9	22.1 ± 1.3	19.5 ± 1.4	21.9 ± 1.5
Benzoic acid	168.3^b ± 39.7	179.3^b ± 19.3	291.7^a ± 22.5	286.6^a ± 12.6
Coumaric acid	489.1^a ± 142.5	484.6^a ± 80.4	268.2^ab ± 70.2	190.3^b ± 6.2
3,4-Dihydroxybenzoic acid	4.5^bc ± 1.2	2.6^c ± 0.6	11.1^a ± 2.3	6.7^b ± 1.3
Ferulic acid	25.2^a ± 4.8	26.6^a ± 3.5	19.7^a ± 4.5	9.5^b ± 2.2
3-Hydroxybenzoic acid	0.2^Ab ± 0.1	0.2^Ab ± 0.1	0.7^a ± 0.3	0.5^ab ± 0.1
4-Hydroxybenzoic acid	48.1^a ± 10.1	37.4^ab ± 3.7	35.6^ab ± 6.8	30.2^b ± 1.9
Sinapic acid	1.2^b ± 0.2	1.6^a ± 0.2	0.2^Ac ± 0.0	0.1^c ± 0.0
Syringic acid	9.6^a ± 1.4	6.9^b ± 1.0	10.1^a ± 0.5	6.2^b ± 0.5
Vanillic acid	29.0^c ± 4.2	22.8^c ± 2.9	55.2^a ± 3.7	39.8^b ± 3.9
8,8′ Diferulic acid	3.8^a ± 1.0	2.1^b ± 0.5	2.1^b ± 0.8	0.9^b ± 0.2
8,5′ Diferulic acid	0.3^a ± 0.1	0.1^Ab ± 0.0	0.2^b ± 0.0	<0.2 ^Ab
8,8′ Diferulic acid (THF)	0.1^b ± 0.0	0.1^a ± 0.0	0.1^Ab ± 0.0	0.1^b ± 0.0
8-O-4′ Diferulic acid	1.4^a ± 0.2	1.2^a ± 0.4	0.9^ab ± 0.2	0.5^b ± 0.1

The data are reported as average ± standard deviation of at least three biological replicates. Values in each row that have different lowercase letter superscripts are statistically different based on Tukey’s 95 % confidence intervals. Rows with no superscript have no statistical difference between the values
^AOne or more replicates were below the limit of detection (LOD). Where all replicates were below the limit, the LOD is reported with no standard deviation. When fewer than all were below the limit, the values were recalculated as LOD/√2. These recalculated values were used to determine the mean, standard deviation, and statistical differences

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