Biofuels can be derived directly from plants, or indirectly from agricultural, commercial and industrial wastes. Basically, it involves generation of biomass that can be converted to convenient energycontaining substances via different ways such as thermal conversion, chemical conversion, and biochemical conversion. These production can also be improved using biotechnology. These are produced through biological processes rather than a fuel produced by geological processes such as coal and petroleum. This biomass conversion can result in fuels which are in solid, liquid, or gas form. Major types are bioethanol or biologically generated alcohols produced via fermentation of sugar and starches by micro-organisms. Bio-butanol, a biofuel, is often a direct replacement for gasoline.
Biodiesel is the most common biofuel in Europe, produced from oils or fats using trans-esterification. Feed stocks for biodiesel include animal fats, vegetable oils, soy, rapeseed, Jatropha, hemp, etc. Other examples are bio-ethers and biogas.
The first commercial-scale plants to produce biofuels from cellulose containing organic matter, have begun operating in the United States. In parts of Asia and Africa where drylands prevail, sweet sorghum is being investigated as a potential source of food, feed and fuel. Since the crop uses very little water, it is particularly suitable for growing in arid conditions.
In India, and other places, sweet sorghum stalks are used to produce biofuel by squeezing the juice and then fermenting into ethanol. Several groups in various sectors are conducting research on Jatropha curcas, which produces seeds considered to be a viable source of biofuels feedstock oil. Current research focuses on improving the overall oil yield of Jatropha through biotechnological techniques.
