Using low temperature to balance enzymatic saccharification and furan formation during SPORL pretreatment of Douglas-fir

Abstract

tComparing analytical results for Sulfite Pretreatment to Overcome the Recalcitrance of Lignocelluloses(SPORL) of Douglas-fir (Pseudotsuga menziesii) at two different temperatures shows that the apparentactivation energy of sugar degradation is higher than that of hemicellulose hydrolysis, approximately161 kJ/mole versus 100 kJ/mole. Thus, one can balance the production of degradation products againsthemicellulose hydrolysis and therefore the enzymatic saccharification efficiency of the resultant sub-strate by changing pretreatment temperature and duration. Specifically, pretreatment at 165°C for75 min significantly reduced furan formation compared with the pretreatment at 180°C for 30 min whilemaintaining the same pretreatment severity and therefore the same substrate enzymatic digestibility(SED). Obtaining high SED with Douglas-fir is also limited by lignin content. Fortunately, the bisulfitein SPORL provides delignification activity. By combining kinetic models for hemicelluloses hydrolysis,sugar degradation, and delignification, the performance of pretreatment can be optimized with respectto temperature, duration, acid, and bisulfite loading. The kinetic approach taken in this study is effectiveto design viable low temperature pretreatment processes for effective bioconversion of lignocelluloses.

Citation

Zhang, C.; Houtman, C.J.; Zhu, J.Y. 2014. Using low temperature to balance enzymatic saccharification and furan formation during SPORL pretreatment of Douglas-fir. Process Biochemistry, Volume 49, 2014; pp. 466-473.