Oxidation is a pretreatment option whereby an oxi­dizing agent, such as hydrogen peroxide or peracetic acid, is applied to LB. The result is the removal of hemi — cellulose and lignin and thus, an increased accessibility to cellulose to enzymatic hydrolysis. This result is the culmination of several reactions: electrophilic substitu­tion, displacement of side chains, cleavage of alkyl aryl ether linkages, or the oxidative cleavage of aromatic nuclei (Hon and Shiraishi, 2001). Often the oxidative agent is not selective and a significant loss of hemicellu — lose and cellulose may occur. Additionally, there is a high risk of forming downstream inhibitors as soluble aro­matic compounds are formed while the lignin oxidizes.

When using hydrogen peroxide as the oxidative agent on sugarcane bagasse, the rate of enzymatic hy­drolysis improves. In one study, hemicelluloses and approximately 50% lignin were solubilized by 2% hydrogen peroxide at 30 ° C over 8 h. This was followed by enzymatic hydrolysis, or saccharification, using cellulase at 45 °C within 24 h. The result was 95% effi­ciency in glucose production (Azzam, 1989).

In another study, peracetic acid was applied at ambient temperatures to a hybrid poplar and sugarcane bagasse mixture (Teixeira et al., 2000). It was determined that peracetic acid was very selective for lignin and in some cases, no significant carbohydrate was lost. When peracetic acid was applied at 21%, the enzymatic hydrolysis of cellulose increased from 6.8% for un­treated biomass to 98% in the peracetic acid-pretreated biomass.