Lipases (triacylglycerol lipases EC are enzymes which have been classically employed to carry on hydrolysis of triglycerides with concommitant production of free fatty acids. However these enzymes also display catalytic activity towards a large variety of alcohols and acids in ester synthesis reactions provided that the water activity is very low. Synthesis of esters mediated by lipases have been under scrutiny by numerous researchers in recent years as a wide variety of such compounds are important to us. In fact,compounds like trigylcerides, phospholipids, galactolipids, cutin, waxes, short chain esters and steroids play many important functions: energy sources, membrane constituents, emulsifiers , viscocity builders, protective coatings flavours. Functional properties of carboxylic esters are directly related to the length of the hydrocarbon backbone. Hence, esters of short and medium chain carboxylic acids and alcohol moities play a relevant role in the food industry as flavour and aroma constituents, whereas methyl and ethyl esters of long chain carboxylic acid moieties provide valuable oleochemical species that may function as fuel for the diesel engines , and esters of long chain carboxylic acid and alcohol moieties (typically referred to as waxes) have applications as lubricants and additives in cosmetic formulations. Esterification by lipases appears to be an attractive alternative to bulk chemical routes.In fact,ester synthesis can be performed at room temparature and pressure, as well as neutral pH in reaction vessels operated either batchwise or continuosly. Products obtained therefore are ,qualitatively, more pure than the ones obtained by alternative chemical means because chemical catalysis tends to be unspecific and consequently generate several by-products . Therefore use of lipases to carry out esterification alleviates the need for a wide variety of complex post-reaction separation processes (which are a must in chemical processes), and thus leads to lower overall operation costs.

Lipase catalyzed reactions however have a major inconvenience associated herewith : the conversions are relatively low when compared with traditional chemical processes if crude commercial enzyme preparations are employed. These intrinsically low volumetric productivities may lead to products quantitatively less pure than those obtained via chemical synthesis (which are more versatile in the sense that processing conditions may be changed within much wider ranges), and such drawback can then be coupled with inhibition of the biocatalyst by products and/or substrates and deactivation of the biocatalyst by heat(thermal deactivation) or by several compounds (chemical deactivaton).

Protein Engineering of enzymes is an indispensable tool for improving the enzyme properties. The properties of lipases that need to be improved are stability and turnover under application conditions. Lipases need to be stable against proteolytic action, they need to be thermostable and also stable against oxidative compounds and detergent ingredients, when lipases are used for fatty stain removal in laundry. A desire for kinetic changes is more likely in the food, chemical and pharmaceutical areas.More understanding is needed concerning the observed stereopreference of lipases acting on triacylglycerol lipases or of pharmaceutical compounds of interest.

The most commercially important field of application for hydrolytic lipases is their addition to detergents, which are used mainly in household and industrial laundry and in household dishwashers. Enzymes can reduce the environmental load of detergent products, since they save energy by enabling a lower wash temperature to be used; allow the content of other, often less desirable, chemicals in detergents to be reduced; are biodegradable, leaving no harmful residues; have no negative impact on sewage treatment processes; and, do not present a risk to aquatic life. Enzyme sales in 1995 have been estimated to be US$30 million, with detergent enzymes making up 30%. An estimated 1000 tons of lipases are added to the approximately 13 billion tons of detergents produced each year. In 1994, Novo Nordisk introduced the first commercial lipase, Lipolase, which originated from the fungus T. lanuginosus and was expressed in Aspergillus oryzae. In 1995, two bacterial lipases were introduced — Lumafast from Pseudomonas mendocina and Lipomax from Pseudomonas alcaligenes, both produced by Genencor International.

Novo Nordisk markets a range of enzymes for various industrial purposes.

S.No Brand Name Type Of Enzyme Main Application
1 Lipopan® Lipase Baking industry
2 Lipozyme® Lipase Oils and fats industry
3 Novozym® 27007 Lipase Pasta/Noodles
4 PalataseTM Lipase Dairy industry
5 Clear-LensTM LIPO Lipase Personal care industry
6 Greasex Lipase Leather
7 LipolaseTM Lipase Detergent industry
8 LipoPrime® Lipase Detergent industry
9 NovoCorTM AD Lipase Leather industry
10 Novozym® 735 Lipase Textile industry
11 Novozym® 871 Lipase Pet Food Industry

The vast variety of synthetic pharmaceuticals and agrochemicals containing one or more chiral centres, are stll being sold as racemates. This is despite the fact that the desired biological activity resides in one particular enantiomer. The usefulness of lipases in the preparation of chiral synthons is well recognised. Among more than 2,500 known enzymes, very few (mainly lipases and in some cases proteases and esterases ) have been used in bulk organic synthesis.

Lipases are also extensively used in the dairy industry for the hydrolysis of milk fat. Current applications include the flavour enhancement of cheeses, the acceleration of cheese ripening , the manufacturing of cheese like products, and the lipolysis of butterfat and cream. The free fatty acids generated by the action of lipases on milk fat endow many diary products, particularly soft cheeses, with their specific flavour characteristics.

The position, chain length and degree of unsaturation greatly influence not only the physical properties but also the nutritional and sensory value of a given triglyceride. Cocoa butter contains palmitic and stearic acids and has a melting point of approximately 37°C, leading to its melting in the mouth, which results in a perceived cooling sensation. Lipase-catalysed transesterification of cheaper oils can be used, to produce cocoa butter from palm mid-fraction.

Another application is the use of lipases in removing the pitch from pulp produced in the paper industry

Lipases are indeed one of the most versatile enzymes. In the coming years there is going to be a large scale commercial exploitation of these enzymes .