Depletion of fossil fuels at an alarming rate in past few decades in association with global warming has led to the search of an alternative fuel which could fulfill the demand of energy, worldwide. In addition to this, it should also be renewable, sustainable and eco-friendly. Biodiesel has emerged as one of the promising options for replacing conventional fuels. Numerous factors like renewability, non-toxicity, biodegradability, less pollutant emission when compared to conventional diesel are responsible for the overall acceptance of biodiesel as an alternative. It is usually produced from vegetable oil, animal fats, non-edible oil, waste cooking oil, and microorganisms (microalgae, yeasts etc.). The uses of these feedstock, especially non-edible oil, waste cooking oil, and oleaginous microorganisms are cost effective and gained considerable attention in research field. In this respect, numbers of researches are done to investigate the better way of producing biodiesel as an alternative fuel. Accordingly, this review paper examines the latest technologies used for biodiesel production.
