Ensiling and hydrothermal pretreatment of grass: consequences for enzymatic biomass conversion and total monosaccharide yields

Table 3 Compositions of solid fractions after HTT treatments at different temperatures (°C)

Biomass	Grass			Grass silage
HTT temperature	170	180	190	170	180	190
	(w/w)% of DM			(w/w)% of DM
Glucan	31.2^d ± 0.45	33.0^d ± 0.16	35.0^cd ± 0.43	36.9^c ± 0.43	40.6^b ± 0.00	42.8^a ± 1.10
Xylan	18.7^a ± 0.40	17.1^b ± 0.05	10.3^c ± 0.09	19.1^a ± 0.09	17.5^b ± 0.35	10.0^c ± 0.21
Arabinan	2.7^a ± 0.01	1.8^b ± 0.07	1.0^d ± 0.00	2.7^a ± 0.00	1.3^c ± 0.01	0.5^e ± 0.01
Klason lignin	18.8^a ± 0.59	19.0^a ± 0.67	17.0^a ± 0.58	13.8^b ± 0.58	13.5^b ± 0.07	13.9^b ± 0.30
Ash	7.4^ab ± 0.52	8.2^a ± 0.18	8.4^a ± 0.11	7.8^ab ± 0.11	6.8^b ± 0.09	6.8^b ± 0.02
Ethanol Extractives	11.8^c ± 0.35	16.4^b ± 0.49	22.8^a ± 0.86	15.4^b ± 0.16	18.2^b ± 0.76	24.5^a ± 0.61
Residual	9.5	4.4	5.6	4.2	2.2	1.4
DM recovery in solid fraction	75.3	69.6	61.6	67.5	61.5	58.8

Numbers are presented as weight percentages of DM in the HTT solid fraction, followed by standard deviations (except for ‘DM recovery in solid fraction’, which is the percentage of DM left in solid fraction after HTT pretreatment, based on mass balance after HTT pretreatment. Different superscript letters indicate significantly different values (P <0.05) row-wise; (similar superscript letters indicate no statistically significant difference). DM, dry matter; HTT, hydrothermal treatment.

ISSN: 2731-3654