Improving enzymatic saccharification of Eucalyptus grandis branches by ozone pretreatment

Ozonolysis is potentially an effective method for pretreating lignocellulosic biomass to improve the production of fermentable sugars via enzymatic hydrolysis. The eliminated branches from eucalyptus trees can represent a production of around 30 million m³ of lignocellulosic material annually only in Brazil. Attempts of developing strategies for a rational use of this biomass are, thus, welcome. In this study, Eucalyptus grandis branches were pretreated with ozone in an attempt to increase enzymatic saccharification. Ozonolysis resulted in the degradation of lignin with negligible losses of cellulose and small losses of hemicellulose. Reduction in the lignin content from 26.63 to 9.53% already resulted in the maximal improvement of the saccharification yield (from 20 to 68%). The results indicate that ozone pretreatment can be a promising way of increasing the enzymatic digestibility of eucalyptus sawdust from eliminated branches of trees for its conversion into fermentable sugars.