In this book, the authors present current research in the study of bioenergy systems and their biological sources and environmental impact. Topics discussed include the assessment of sustainability of bioenergy systems; soil loss as a forgotten aspect of biofuel production; effective biocatalysts for lignocellulosic biofuel by a proteomics study of fungal secretome; enhancing the interface between agricultural production, and tree biomass/bioenergy systems to improve farm-scale productivity in Western Australia; hydrogen and ethanol comparison as fuels for internal combustion engines; and hydrogen production by mixed cultures.