ABSTRACT
The world has fuel-driven economies, and as an integral part of day-to-day life, one cannot imagine the world without it. The dependency on conventional fuels such as coal, petroleum, derived fuels, firewood, etc., are non-renewable resources and potentially contribute to the evolution of greenhouse gases (GHGs), which in turn results in climate change. Fuel is the core part, and its casual use led to its untimely exhaustion and increased levels of harmful gases. Whereas biofuels could be a bypass for such negative impacts imposed due to the use of conventional carbon-based fuels. Biofuels, such as ethanol, have a well-established market in many countries and show prospects for using such greener fuels obtained with the help of microorganisms. Microbial cells act as a catalyst and catalyze the conversion of waste organic raw material to fuels. Whole-cells as catalysts display potential for future applications, and this chapter elaborates on the different types of chassis used, and initial raw materials consumed and converted in 310the various types of carbon-based and carbon-free fuels. This technology has shown promising results for sustaining in the future in alliance with environmental health.
