ABSTRACT
The demand for bioenergy is fast picking up with growing climate change policies and with a growing need for independence from fossil-based energy. Biowaste has been identified as a low-cost, widely available renewable source for the sustainable generation of biofuels. Various advantages have been cited for use of biowaste for biofuel generation like reduced dependency on fossil reserves for energy, minimized greenhouse gas emissions, minimized health and environmental risks, and reduced environmental burden of biowaste disposal. The liquid biofuels like bioethanol and biodiesel generated via microbial fermentation and transesterification are widely in use as a transportation fuel and steadily replacing traditional fuels like gasoline and diesel. Gaseous biofuels like biogas are upgraded to generate electricity for household purposes, used as transportation fuel, besides being used for cooking or lighting purposes. Global production of biofuels in the year 2018 was 154 billion liters and the forecast is that the production rate is expected to increase to 25% by 2024. The major use of biofuels is expected to be in the transport sector. Since transport accounts for 30% of global energy usage, the use of biofuels is important for ensuring a sustainable energy future. With this backdrop, the chapter gives an overview of the different biological technological transformations of biowastes to biofuels (biogas, bioethanol, 52biodiesel, and biohydrogen). The advancements made to date in anaerobic digestion, microbial fermentation, and dark fermentation are discussed, and the different biowastes used successfully are highlighted along with critically discussing of the major hurdles that have led to lower biofuel yield. The future scope rests on strong policy support along with innovation to reduce costs. This will ensure the scaleup of biofuel consumption and application.
