Bioethanol G2: Production process and recent studies

Abstract

The demand for ethanol as a substitute of gasoline is rapidly increasing due to the recent increase of imbalance in oil market and interest in environmental issues. First-generation (G1) bioethanol which is currently derived mainly from food crops generate many problems such as net energy losses, greenhouse gas emission, and increased food price. On the other hand, biofuel produced from lignocellulosic materials, so-called second-generation (G2) bioethanol, shows environmental advantages in comparison to G1. The development of bioethanol G2 from lignocellulosic materials possesses many advantages from energy and environmental aspects. Efficient conversion of lignocellulosic biomass to ethanol and value-added biochemicals is still today a challenging proposition. Basically, four steps are included in the production process of bioethanol G2, composed of pretreatment, saccharification, fermentation, and product separation/purification. In each step, there are several ideas to improve its productivity and benefitability. In this chapter, we describe some details about the production process selection or ideas. New studies such as catalytic conversion of lignocellulosic biomass are also rapidly developing, although they are not yet mature to be utilized for industrial purposes.