Oxidative Delignification
Oxidative delignification involves treatment of biomass with oxidizing agents, such as ozone, hydrogen peroxide, or oxygen. Oxidizing agents with aromatic rings convert lignin polymer into carboxylic acids, which are inhibitors of microorganisms. However, part of the hemicellulose fraction of biomass may be degraded. In ozonolysis, degradation is limited to lignin, whereas hemicellulose and cellulose are not degraded [21]. The rate of enzymatic hydrolysis of ozone-treated biomass is increased because of lignin removal through pretreatment. Ozonolysis oxidations are more effectively conducted in hydrated fixed bed than in aqueous suspension. These experiments are conducted at room temperature and ambient pressure. Ozone is expensive; however, it can be easily decomposed and can minimize environmental pollution.