Rates of enzymatic hydrolysis of milled wood particles from wild-type (WT) and transgenic poplar lines from materials treated with TFA with or without catalytic delignification (CDL). a Progress of enzymatic hydrolysis of material untreated (black lines), swollen in TFA at –20 °C (blue lines), or gelatinized in TFA at 55°C (red lines). b Progress of enzymatic hydrolysis in untreated materials (black lines), CDL-treatment materials (blue lines), or CDL-treated materials swollen in TFA at –20 °C (red lines). WT = (Populus tremula × P. alba cv. INRA 717-1B4), high S-lignin = pAtC4H:AtF5H1, high G-lignin = pAtC4H:PtF5H2 RNAi, and high OH-G-lignin = p35S:PtCOMTa RNAi. Enzyme hydrolysis was initiated by addition of 1 μL (0.09 FPU) of Cellic® Ctec2 (Novozymes) to 5 mg of milled particle preparations in 2 mL of 50 mM sodium citrate, pH 5.0, and incubated at 50°C for up to 72 h. Values are the means ± S.D. of three determinations.