The development of a biobased economy is highly dependent on efficient and sustainable refining of agroindustrial wastes for the production of fuels and energy. Recent researches on biorefinery engineering leads to the integrated and sustainable processes of bioconversion of renewable resources aiming to maximize the efficiency of abundunt and inexpensive resource utilisation. Agroindustrial wastes should be considered as raw materials for the creation of novel biorefinery concepts corresponding to the establishment of a circular economy, for instance bioethanol production. Appropriate bioethanol production design should be employed in order to screen processing options and optimum biorefining concepts. This book covers bioethanol production related to biorefinery engineering starting from the shaking flasks determining the appropriate fermentation conditions to the usage of agroindustrial wastes in bioreactors to highlight their potential to be commercialized.