Release of sugars from lignocellulosic biomass is inefficient because lignin, an aromatic polymer, blocks access of enzymes to the sugar polymers. Pretreatments remove lignin and disrupt its structure, thereby enhancing sugar release. In previous work, enzymatically generated peracetic acid was used to pretreat aspen wood. This pretreatment removed 45% of the lignin and the subsequent saccharification released 97% of the sugars remaining after pretreatment. In this paper, the amount of enzyme needed is reduced tenfold using first, an improved enzyme variant that makes twice as much peracetic acid and second, a two-phase reaction to generate the peracetic acid, which allows enzyme reuse. In addition, the eight pretreatment cycles are reduced to only one by increasing the volume of peracetic acid solution and increasing the temperature to 60 °C and the reaction time to 6. h. For the pretreatment step, the weight ratio of peracetic acid to wood determines the amount of lignin removed.
Bibliographical noteFunding Information:
We thank the Institute for Renewable Energy and the Environment at the University of Minnesota, the National Science Foundation ( CBET-0932762 ) and the Korea Science and Engineering Foundation funded by the Ministry of Education , Science and Technology (WCU program R32-2008-000-10213-0) for financial support.
- Peracetic acid