A combination
of physical and/or chemical pretreatment methods appears
to be a better approach to both obtain more purified
cellulose content and to enhance digestion. Several combined pretreatment
technologies have been reported, such as a combination
of sulfuric acid-free EtOH heat treatment followed by mechanochemical
pulverization, hot-water followed by aqueous ammonia
pretreatment, and H2O2 followed by biological pretreatment