Pretreatment as the crucial step for a cellulosic ethanol biorefinery: testing the efficiency of wet explosion on different types of biomass.

The efficiency of wet explosion applied as modified dilute acid pretreatment at previously identified reference conditions (150°C, 0.3% H(2)SO(4), 15 min) was investigated on lucerne, ryegrass, fescue grass, cocksfoot grass, rye fescue, forage grass, and wheat straw in order to identify their potential as feedstock for cellulosic bioethanol production. After pretreatment, cellulose recovery was more than 95% for all biomass while enzymatic convertibility of cellulose ranged from 40% to 80%. Lower enzymatic conversion of cellulose was correlated with higher lignin content of the biomass. Hemicellulose recovery was 81-91% with a final pentose yield of 65-85%. Cocksfoot grass and wheat straw had the highest bioethanol potential of 292 and 308 L/ton DM, respectively. Overall efficiencies were higher than 68% for cocksfoot grass harvested in August, fescue grass, wheat straw, and forage grass while efficiencies were lower than 61% for the other tested biomass resources, making further adjustment of the process parameters necessary.