Book excerpt: This book focuses on the different kinds of biofuels and biofuel resources. Biofuels represent a major type of renewable energy. As part of a larger bio-economy, they are closely linked to agriculture, forestry and manufacturing. Biofuels have the potential to improve regional energy access, reduce dependence on fossil fuels and contribute to climate protection. Further, this alternative form of energy could revitalize the forestry and agricultural sector and promote the increased use of renewable resources as raw materials in a range of industrial processes. Efforts are continuously being made to develop economically competitive biofuels, and microbes play important roles in the production of biofuels from various bioresources. This book elaborates on recent advances in existing microbial technologies and on sustainable approaches to improving biofuel production processes. Additionally, it examines trends in, and the limitations of, existing processes and technologies. The book offers a comprehensive overview of microbial bioresources, microbial technologies, advances in bioconversion and biorefineries, as well as microbial and metabolic engineering for efficient biofuel production. Readers will also learn about the environmental impacts and the influence of climate change on the sustainability of biofuel production. This book is intended for researchers and students whose work involves biorefinery technologies, microbiology, biotechnology, agriculture, environmental biology and related fields.