Effect of Steam Explosion Pretreatment with Explosive Decompression on Enzymatic Digestibility of Biomass

Steam explosion pretreatment is currently the most common pretreatment method for enhancing enzymatic digestibility of lignocellulosic biomass in commercial biorefineries. However, knowledge of the effect of explosive decompression on enzymatic digestibility is very limited. Thomas Pielhop from ETH Zurich in Switzerland now aim to discover the effect of adding explosion to steaming and identify their individual effects on enzymatic digestibility.

Explosive decompression in the steam explosion pretreatment of spruce wood chips had a high influence on digestibility, improving it by up to 90% compared to a steam pretreatment alone. Pretreatment severity and pressure difference of the explosion were identified as factors responsible for the effect on enzymatic digestibility.

A higher pretreatment severity can weaken the lignocellulose structure, so that the explosion can better break up the biomass, enhancing its digestibility. On the other hand, increasing the pressure difference of the explosion leads to more defibration, a smaller particle size and a better digestibility. Therefore, the only influence of the explosion on digestibility was macroscopic particle size reduction.