Fig. 6

The pretreatment process for conversion of milled poplar wood into terpenes. a For pretreatment, the reactor contained 25 or 30% biomass and 10% cholinium lysinate ([Ch]⁺ [Lys]⁻), heated to 140 °C and stirred for either one or three hours. b Sulfuric acid 50% (v/v) was used to adjust the pH to between 4.8 and 5. The enzymes CTec3:HTec3 (or CTec2:HTec2) in a ratio of 9:1 (v/v) were added at 30 mg per gram of untreated biomass. The reactor was heated to 50 °C and stirred for 72 h. c R. toruloides was then added and grown at 30 °C for six days. In some cases, the hydrolysate was filtered beforehand