Transesterification process Biodiesel may be produced in batches or continuously by transesterifying triglycerides such as animal fat or vegetables oils with alcohol in presence of a base or acid catalyst. Transesterification process is the process of separating the fatty acids from their glycerol backbone to form fatty acid esters (FAE). Free fatty acid level and moisture percentage are parameters for determining the viability of transesterification process. Transesterification is classified as give below. 1.
Biodiesel uses the same properties of diesel as fuel for cars. Biodiesel has many sources for it to be produced, these include soya, canola, jatropha, sunflower seed, etc. and animal fats (Khemani, 2011). Most of the used cooking oil thrown end up being collected to produce biodiesel; most restaurants donate their used cooking oil to prevent from throwing it in the drain. Rudolf Diesel who invented the diesel engine conducted an experiment by using vegetable oil as fuel for is engine (Pacific Biodiesel).
Biodiesel is produced from vegetable oils, used cooking oils, and animal fats by the production process called “trans-esterification” to convert those mixtures to the chemicals which have long chain mono alkyl esters or fatty acid methyl esters which can be used as “fuel” for vehicles. Approximately, 100 pounds of vegetable oil react with 10 pounds of alcohol (commonly methanol) in the presence of a catalyst, sodium hydroxide; later, 100 pounds of biodiesel and 10 pounds of glycerol (co-product) can be produced. For the glycerol which can be used for pharmaceuticals and cosmetics. Therefore, biodiesel can be considered as totally natural, alternative fuel source to be available for using in most of cases as similar as petrol or more specifically, “diesel distilled from petroleum”. Biodiesel is much safer than diesel from petroleum when biodiesel is escaped to the surrounding environment; moreover, it is much less inflammable as biodiesel’s flashpoint is 130°C as compared to petroleum diesel which is only 52°C.
2. Biodiesel [1,2] At the early of eighteenth century, a novel diesel engine developed by Rudolf Diesel, a famous inventor, who first introduced peanut oil as alternative source to run on diesel engine in 1823 and widely use as the emergency fuel from time to times. However, the drawbacks from vegetable oils uses including fuel costs, shortages and effects on the engine efficiency in several properties were considered. In 1937, Belgian inventor who purposed a chemical process that can convert vegetable oils into fatty acid alkyl esters form, known as Biodiesel. Biodiesel (Fatty acid methyl esters - FAME) derived from triglycerides conversion into methyl or ethyl esters forms via transesterification process which is a reaction of fat or oil
Extracted from vegetable oils, animal fats, seeds from plants like Soybeans, Canola, and Sunflower are few of the examples. This fuel is commonly used in means of transportation. (2) Ethanol. This is acquired through fermentation process. Sugar cane and starch crops like Corn and Wheat are few of the examples.
However, it is well accepted that glycerol mass formation is currently achieved through the transesterification process due to the dramatic increase in the capacity of biodiesel production . Biodiesel is a biodegradable and renewable fuel that comprises of fatty acid methyl esters produced by transesterification of glycerides with methanol. With the increasing in worldwide biodiesel production, resulting in a major concern on the by-product generated from of biodiesel produced by transesterification process. The market for the glycerol by-product of biodiesel production (transesterification process) was rapidly becoming saturated and created excess glycerol of less value as its supply exceeded its demand. Palm oil industry of Malaysia has historically made the country a major player in the biodiesel production that directly influences glycerol market.
Ye at al.  prepared potassium sodium tartrate on alumina/silica support by a sol-gel process for transesterification of soybean oil. When the transesterification was carried out in a microwave reactor with a molar ratio of methanol to oil of 13 and a catalyst concentration of 8.0wt% at 65°C for 45 min, the highest biodiesel yield reached 96.5%. Hsiao et al.  found for transesterification of soybean oil over nano CaO assisted by microwave irradiation, the optimal reaction took place at a methanol to oil molar ratio of 7, amount of catalyst of 3.0 wt.% and temperature 60oC, achieving a conversion of 96.6% at 60 min.
Bio-diesel production yields undesirable by-products for example methanol and glycerin. These by-products are removed so that the bio-diesel is suitable for use. Fractional distillation is used in the essential oil, flavor and fragrance industry. Raw essential oils are extracted from different plants such as mint, clove and tee tree for example. These raw oils contains impurities that have a bad flavour or odor.
Nowadays, the application of lipase as biocatalyst for biodiesel synthesis also increased rapidly. Immobilized Enterobacter aeruginenes lipase was used for the transesterification of Jatropa oil in t. butanol solvent for the production of biodiesel with the maximum yield of 94% (Kumari et al. 2009). Lipase was also reported in the production of biodiesel by transesterification of vegetable oil such as sunflower oil and soybean oil (Leca et al. 2010).