TABLE 10.

Fate of biomass components for various pretreatment processes

ProcessFate of biomass components under conditions leading to high cellulose digestibilityReference(s)
CelluloseHemicelluloseLignin
Dilute-acid pretreatmentSome depolymerization80-100% solubilization, primarily to monomersLittle or no solubilization, extensive redistribution223, 599, 671, 685
Steam explosion at high solids concentrationSome depolymerization80-100% solubilization to a mixture of monomers oligomers, and degradation productsLittle or no solubilization, extensive redistribution87, 248, 546
Hydrothermal processes (see the text)Some depolymerization80-100% solubilization, oligomers usually >50%Partial solubilization (e.g., 20-50%)64, 372, 460b
Organic solvents with waterSubstantial solubilization (varies but can be nearly complete)Substantial solubilization (varies but can be nearly complete)110, 278
AFEXSome decrystallizationSolubilization from 0 to 60% depending on moisture; ∼90% hydrolyzed to oligomersSome solubilization (∼10-20%)132a
Sodium hydroxide pretreatmentSubstantial swelling, type I → type IISubstantial solubilization (often >50%)Substantial solublization (often >50%)726
Lime pretreatmentSignificant solubilization (to 30%) under some but not all conditionsPartial solubilization (∼40%)96, 319
  • a Also, B. E. Dale, personal communication.

  • b Also, R. Torget, personal communication.