Nine billion. This is the estimated number of people who will inhabit our planet in 2050. In a few decades, we will have nearly a quarter more than humans circling the globe in search of food, shelter, clothing and other manufactured products. Among the new individuals, the United Nations (UN) estimates that 98% will live in developing countries, with the highest level of economic growth, which in turn will result in a considerable expansion in per capita consumption worldwide.

On the one hand we have a significant increase in energy demand and consumption, resulting from population and income growth, and on the other, there is a considerable uncertainty about the world’s available supply of natural resources to support this development. Intergovernmental Panel on Climate Change (IPCC) recent reports have shown strong evidence of the impact of human activity on the climate of the planet. Estimates of the entity warn about a potential increase in global average temperature by up to 5 or 6oC by the end of this century. The raise in temperature itself would cause drastic changes in many ecosystems, but the reports also mention the intensification of extreme weather events such as hurricanes.

This apparently catastrophic scenario for the maintenance of the human species on Earth, opens up several possibilities for what is now called "green" or low carbon economy. We are talking about creating new businesses and industries geared to develop products and services with low consumption of natural resources and reduced emission of greenhouse gases. Within this category of business, biofuels is a highlight and the central theme of this book.

Biofuels are now the main alternative to automotive fossil fuels due to the fact that they are produced from renewable sources such as sugar cane, corn, cassava, oil seeds, agricultural waste, algae, etc.. Ethanol from sugar cane produced in large scale in Brazil, for example, illustrates the benefits of these products. Its production costs are low, which makes it competitive with oil derivatives. Each unit of fossil energy used in ethanol production is reversed in eight to nine units stored in the fuel. Finally, one of the most important qualities, each cubic meter of sugarcane bioethanol used as fuel reduces from 1.7 to 1.8 tonnes of CO2 (equivalent) emitted into the atmosphere. Due to the flex-fuel engine technology, more than 90% of light vehicles produced in Brazil are now able to run on 100% fuel ethanol.

The successful history of Brazilian ethanol is undoubtedly the first successful case of production and use of a biofuel in large scale, but is far from being the last. From the beginning of the century, two main factors have made the world turn its attention to research on biofuels. The first, already mentioned, is the increasing debate on climate issues. The second is the raise in the price of the oil barrel. In 1970, before the first shock in the price of fossil fuel, a barrel costs about $ 3. In 2008 the price was above $ 120. These facts stimulated scientists around the world to focus their research on themes that could result in the diversification of the energy matrix in many countries.

The globalization of the research on biofuels may bring a number of advancements to the industry and has already awakened a wish the market: to also convert cellulose into ethanol. Materials not used in the production of biofuels, such as sugarcane bagasse, corn stover and forest residues can be a significant source of additional ethanol, provided that appropriate industrial technologies are developed. In the case of sugarcane ethanol for example, data from the Brazilian Bioethanol Science and Technology Laboratory (CTBE) indicate that the conversion of bagasse and straw would increase the current production of bioethanol in Brazil in about 50%.

However, the challenges to make this technological potential an industrial reality are numerous and need investment in research and development (R&D). There are technological barriers with respect to the initial treatment of the raw material, production of microorganisms that break down cellulose into fermentable sugars, the fermentation of five-carbon sugars (pentoses), among others.

The new global market of bioenergy that has been structured in recent years has yet another relevant route for exploration: the biorefinery. Similar to the oil industry, it uses different types of processes to transform the same raw material in different products used by many industrial sectors, such as food, pharmaceutical, chemical, etc.. Companies and research institutes have studied and developed processes that convert biomass into raw materials for their production chain, potentially replacing substances that were produced from petroleum. Thus, in most cases, the environmental benefits and the reduction of dependence on fossil fuels are evident. Some studies even indicate that the use of biomass within the biorefinery concept may improve the profitability of cellulosic ethanol technology (second generation) and favor the integration of this new technology with the current first generation process.

The first section of this book presents some results for first generation ethanol production, i. e., from starch and sugar raw materials, which include cassava, sorghum, and sugarcane. In the second section, the chapters present results on some of the efforts being made around the world in order to develop an efficient technology for producing second-generation ethanol from different types of lignocellulosic materials. While efficient ethanol production technologies are being developed, one can also start thinking about different uses for it. In addition to the more straightforward use as fuel, it is worth to study other applications. The chapter in the third section points to the use of hydrogen in fuel cells, where this hydrogen could be produced from ethanol.


The editors would like to acknowledge Luiz Paulo Juttel for contributing with the information in the preface and the board of referees that made the technical revision of the chapters:

Antonio Bonomi Arnaldo Cesar da Silva Walter Carlos Eduardo Vaz Rossell George Jackson de Moraes Rocha Manoel Regis Lima Verde Leal Marcos Silveira Buckeridge Oscar Antonio Braunbeck

Marco Aurelio Pinheiro Lima and Alexandra Pardo Policastro Natalense

Brazilian Bioethanol Science and Technology Laboratory (CTBE),