By Deepak Kumar, Stephen P. Long and Vijay Singh

The aviation industry produces two percent of global human-induced carbon dioxide emissions. This share may seem relatively small—for perspective, electricity generation and home heating account for more than 40 percent—but aviation is one of the world's fastest-growing greenhouse gas sources. Demand for air travel is projected to double in the next 20 years.

Airlines are under pressure to reduce their carbon emissions, and are highly vulnerable to global oil price fluctuations. These challenges have spurred strong interest in biomass-derived jet fuels. Bio-jet fuel can be produced from various plant materials, including oil crops, sugar crops, starchy plants and lignocellulosic biomass, through various chemical and biological routes. However, the technologies to convert oil to jet fuel are at a more advanced stage of development and yield higher energy efficiency than other sources.