Currently, in the U.S. biodiesel is commonly made from soybean oil, in the EU rapeseed, sunflower or soybean oil are used, and in Southeast Asia, palm oil is used. However, many are shifting into the exploration of non-edible oil feedstocks in the event of the food vs fuel conflict.
The chemical approach is a well-developed technology that has been commercialized worldwide for the production of biodiesel. Though significant efforts have been placed in the up-gradation of this process; however, it still has high manufacturing costs and environmental concerns, e.g. chemical disposal, wastewater and poor quality of the glycerol co-product. As major chemical approaches are embraced of the alkaline process, the production is bounded to only the transesterification reaction. It cannot handle the conversion of free fatty acid (FFA) effectively and frequently results in the formation of soap. On the flip side, the acid process is restricted only to the esterification reaction, that is, conversion of FFA into biodiesel, as the rate of transesterification is prolonged to make it feasible for commercial production. Thus, if an oil source contains a large amount of FFA, then only a blend of the acid and alkaline processes can completely utilize the feedstock oil. As a result, the production cost is doubled, as well as the operating cost, leading biodiesel to cost higher than petroleum diesel.
A clean and environment-friendly technique for biodiesel production is through enzymatic process. It can concurrently convert both the FFA and the triglyceride in biodiesel. However, through many years, it has been stereotyped into having prolonged reaction times and high operating costs, due to the high lipase.
Enzyme preparations, which are used for biofuels manufacturing, are similar to those used in the production of different foods, that include bread and beverages. One may ask whether the safety status of enzymes used in fuel ethanol production has any difference from that of enzymes used in near-identical processes for the production of food products such as beer or alcoholic beverages.
