Biomass Dynamics

 Some of the cost associated with biorefineries comes from the requirement to heat biomass to high temperatures to soften and process lignin. A more dynamic lignin is industrially beneficial as it has a lower softening (glass transition) temperature and thus it should have a lower associated processing cost. These fundamental results obtained reveal two insights of practical importance. The softening of lignin occurs at lower temperatures when whole biomass is thermochemically pretreated  (a process that necessarily includes a relatively high amount of water) than when drier isolated powder lignin is heated up. To reduce the lignin processing temperature, the cooling phase of the processing should be prolonged (heating should be shortened) and feedstocks whose lignin has a higher syringyl content should also be used [Vural, D. et al.;Smith, J.C.; Petridis, L.].  
Atomic-level description of lignin atomic dynamics reveal that lignin exhibits localized motions with Arrhenius temperature dependence of the relaxation time below Tg, and segmental collective motions involving 3-5 monomeric units with non-Arrhenius behavior above Tg.