Fig. 2

Sugar release and its relationship to lignin content. Total sugar release (mg per g cell wall residues) from hydrothermally pretreated (a) and unpretreated (b) switchgrass in years 2 and 3 after 72-h enzymatic hydrolysis (the value reported is the average of 5 biological replicates from each control group and 10 biological replicates from each transgenic group. Error bars represent standard errors.) and the relationship of total sugar (glucose and xylose) release for pretreated (c) and unpretreated (d) switchgrass to lignin content (wt% of cell wall residues). An asterisk (*) indicates a significant difference between the transgenic and control groups as determined by a Student’s t test (P < 0.05). ^& The sugar release and lignin content data of year 2 and year 3 plants after pretreatment are from a previous publication [18, 19]