Combining hot-compressed water and ball milling pretreatments to improve the efficiency of the enzymatic hydrolysis of eucalyptus

Table 2 Yields of glucose and xylose recovered from the soluble fraction and residue of eucalyptus pretreated with hot-compressed water

Temperature (°C)	SR^a (%)	Yields of hydrolyzed sugars from				Total yield (%)	CrI^b (%)
		Soluble fraction		Residue
		Glucose (%)	Xylose (%)	Glucose (%)	Xylose (%)
120	99.1	0.1	0.0	3.8	0.0	3.1	60.4
140	96.1	0.3	0.7	5.9	5.3	6.1	62.0
160	85.1	0.3	29.9	23.3	21.5	29.3	67.4
180	70.0	1.1	65.1	50.5	9.8	56.4	69.4
200	66.7	2.3	15.7	74.7	4.1	65.2	74.7
220	62.7	1.2	0.0	72.6	1.3	58.8	ND^c
240	51.8	1.1	0.0	42.5	0.0	34.6	65.6

The glucan and xylan in the soluble fraction were hydrolyzed to monomers with 4% H₂SO₄. The hot-compressed water (HCW)-treated residue (1%) was hydrolyzed with an enzyme cocktail (40 FPU/g substrate) for 72 hours. The yields of glucose and xylose are calculated based on the glucan and xylan contents, respectively, in the dry weight of untreated biomass. Total yield of hydrolyzed sugars is calculated from the combined contents of glucan and xylan in the dry weight of untreated biomass.
^aSolid-remaining yield based on dry weight of HCW-treated residue. ^bCrystallinity index of the HCW-treated residue. ^cNot determined.

ISSN: 2731-3654