We could show that the enzymatic saccharification following a hot water pretreatment of lignocellulosic biomass was enhanced by the use of carbonium ion scavengers. Spruce wood underwent a hot water pretreatment with 2% w/w (based on raw dry biomass) of 2-naphtol, which can act as a carbonium ion scavenger for lignin fragments. In the subsequent enzymatic hydrolysis of the cellulose, the glucose yield could be increased up to 46% compared to the control. We assume that the suppression of lignin recondensation reactions enhanced the digestibility of the cellulose. As a proof of concept, it was shown that crossing agents for lignin fragments in the pretreatment like resorcinol decreased sugar yields [2].
The influence of several pretreatment parameters (severity, scavenger loading, biomass particle size) and a range of potential carbonium ion scavengers (e.g. alcohols, amines) have been studied. Current research focuses on transferring the technology from hot-water to steam (explosion) treatment, which is of more commercial relevance. Results from these studies will be presented.
References
[1] Wayman, M., Lora, J. H.: Aspen autohydrolysis - The effects of 2-naphtol and other aromatic compounds. Tappi 61(6): 55-57 (1978).
[2] Pielhop, T., Studer, M., Rudolf von Rohr, P.: Use of carbonium ion scavengers in the treatment of lignocellulosic biomass. Vol. WO/2013/068092