*1.1.1 Generations of biofuels*

Historically, there are three generations of biofuels. First generation biofuels such as bioalcohols, biodiesels, biogas, bioethers, biosyngas and vegetable oil have been produced primarily from sugar, starch, and vegetable oil sugar, or animal fats, and they are produced through conventional techniques [7]. Advances based on various biomass possibilities have resulted in the development of 2nd and 3rd generation biofuels [8]. Biofuels derived from agroforestry residues lignocellulosic materials and waste biomass (wheat stalks, maize stalks, corn, and wood) as well as dedicated non-food based bioenergy materials (e.g. miscanthus, willow, and poplar), serve as the foundation for second generation biofuel production [9]. Advanced biofuels such as biohydrogen and bioethanol are examples of the second-generation biofuels. Algae-based biofuels such as biogas (biohydrogen and biomethane) are the third generation of biofuels [10].
