. 2017 Feb 7;10:36. doi: 10.1186/s13068-017-0718-z

Table 4.

Ether- and Ester-linked p-coumaric and ferulic acid content in native and steam exploded biomasses

Substrate	Pretreatment severity (CSF)	p-coumaric acid (mg/g lignin)			Ferulic acid (mg/g hemicellulose)
Substrate	Pretreatment severity (CSF)	Ester-linked^a	Ether-linked^b	Total^c	Ester-linked^a	Ether-linked^b	Total^c
Miscanthus × giganteus	Untreated	3.61 ± 0.11	1.20 ± 0.11	4.81 ± 0.08	1.20 ± 0.04	0.82 ± 0.04	2.02 ± 0.03
	2.0	3.18 ± 0.02	0.33 ± 0.05	3.50 ± 0.05	0.21 ± 0.01	0.14 ± 0.01	0.35 ± 0.01
	2.6	2.84 ± 0.08	0.34 ± 0.08	3.18 ± 0.04	0.04 ± 0.00	0.06 ± 0.00	0.10 ± 0.01
	2.7	2.63 ± 0.04	0.39 ± 0.12	3.03 ± 0.08	0.05 ± 0.00	0.05 ± 0.00	0.10 ± 0.01
	2.8	2.66 ± 0.06	0.30 ± 0.07	2.96 ± 0.04	0.05 ± 0.00	0.04 ± 0.00	0.09 ± 0.01
Wheat straw	Untreated	0.82 ± 0.01	0.33 ± 0.01	1.15 ± 0.01	1.22 ± 0.01	0.67 ± 0.01	1.89 ± 0.02
	2.0	0.97 ± 0.01	0.20 ± 0.03	1.18 ± 0.01	0.35 ± 0.03	0.26 ± 0.04	0.60 ± 0.01
	2.6	0.97 ± 0.03	0.24 ± 0.02	1.21 ± 0.01	0.09 ± 0.01	0.16 ± 0.01	0.26 ± 0.03
	2.7	0.96 ± 0.01	0.22 ± 0.01	1.17 ± 0.01	0.08 ± 0.01	0.14 ± 0.01	0.23 ± 0.01
	2.8	0.95 ± 0.02	0.18 ± 0.02	1.14 ± 0.01	0.08 ± 0.01	0.11 ± 0.01	0.19 ± 0.04

All the values are expressed as mean ± SD of triplicate

^aRepresents the ester-linked fraction released during 2 M NaOH hydrolysis at 35 °C for 2 h

^bRepresents the difference between the ester-linked fraction and the total fraction released during NaOH hydrolysis

^cRepresents the ester- and the ether-linked fraction released during 4 M NaOH hydrolysis at 170 °C for 2 h