Commercial uses of Enzymes

The use of enzymes to modify foods has increased vastly and these fermentations are continuing to be important, however, a new type of enzyme industry has evolved which involves the use of harvesting enzymes from microorganisms. The production of enzymes from bacteria and fungi can be isolated from the growth media and cleansed and purified as necessary. Generally in industrial processes the enzyme is immobilised which allows t h enzyme to be re-used and also enable the products to be separated easily. The production of textiles, paper, leather fruit juices and biological detergents are produced from Microbial enzymes.

Enzymes work by breaking down a substrate into simpler molecules. They increase the rate at which a reaction occurs. They lower the activation energy, which results in a quicker rate.

Once the substrate leaves the active site of the enzyme the enzyme is free to combine with another free substrate molecule as long as it will fit into the active site of the enzyme as each enzyme has a specific active site which results in enzymes being specific in what they break down.

The following equation represents the reaction occurring between an enzyme and a substrate:

ENZYME + SUBSTRATE → ENZYME – SUBSTRATE complex → ENZYME + PRODUCTS

Proteases

Proteases hydrolyse peptide bonds in peptides and proteins. They act wither within the peptide chain or by removing amino acid residues in sequence from one or other end of the chain. Proteases can also be known as proteinases and peptidases. Proteases account for about 50% of the commercially used microbial enzymes,

Various fungal enzymes are used in cheese making as an alternative to rennet as they help to clot ...

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The following equation represents the reaction occurring between an enzyme and a substrate:

ENZYME + SUBSTRATE → ENZYME – SUBSTRATE complex → ENZYME + PRODUCTS

Proteases

Various fungal enzymes are used in cheese making as an alternative to rennet as they help to clot milk. Microbial proteases can also be used in clarifying fruit juices and also in beer by terminating the protein haze. They can also be used in the digestion of fish livers to permit improved withdrawal of fish oil, tenderisation of meat and alteration of proteins in flour used for bread making.

Pectinases

The job of pectinases is to degrade pectins, which are polysaccharides, found within plant cell wall structure into shorter molecules, which are known as galacturonic acid. Pectin can turn into jelly that comes in use for products such as jams however not adequate in fruit juices and other liquids. Pectinases are obtained from fungi like Aspergillus’s and Penicillium. Other bacterial and fungal pectinases are used in destroying and rotting of fruits and vegetables. The biggest uses of pectinases are probably in the purification of fruit juices. They are added to fruit that has been crushed like grapes. This increases the yield of the juice extracted and also improves the colour derived from the fruit skins.

Cellulases

These break down cellulose into smaller chains and then into disaccharides cellobiose and to β-glucose. Cellulases currently have little use in the food industry however can be used in improving the release of colour form fruit skins and removing the haze from beer and to tenderise green beans. When cellulases are used in conjunction with ligases, cellulases have a great use in processing waste materials such as sawdust and straw to produce sugars from the cellulose contained in these materials.

Amylases

Glycosidic bonds are hydrolysed by amylases in polysaccharides converting them to dextrins or to maltose. Fungal amylases are used in purifying fruit juices, wines and beers by removing suspended starch.

It can also be used in bread making and brewing because the addition of amylase can yield more sugars from starch in the barley grains and starch in flour. One of the most important uses of amylases is in the conversion of starch to sweet glucose syrup. This can then be used as sweeteners in the food industry as well as in brewing and bread making.

Lactase

Lactases are involved in the breaking own of lactose, which is found in milk. Microbial lactases produced for profits are obtained from Aspergillus. Lactase is extremely important in producing milk for people who are lactose intolerant. The lactose hydrolyses lactose in milk to make it suitable for these people. Lactase is also used to increase sweetness in ice creams as lactose is broken down it turns to galactose and glucose, which are sweeter than lactose. In ice cream manufacturing lactase also removes lactose, which crystallises at low temperatures that would results in a sandy gritty texture.

Biological detergents

Bacterial proteases have an important use in biological detergents which break down protein stains when washing clothes. The proteases present in biological powders include Savinase and Alcalase. They are produce by microorganisms. Proteins help to remove stains like blood, grass and various foods by breaking the proteins down present in these substances. The products produced dissolve in the water.

Enzyme immobilisation

Enzymes used commercially are often immobilised. This is when the enzyme molecules are attached to an insoluble material however this does not affect the enzymes activity. This is good as the products are easy to separate from the enzyme so the enzyme can then be re-used which also reduces costs.

Enzyme immobilisation is used a lot in the production of milk for lactose intolerant people. Immobilised lactase hydrolyses the milk sugar lactose to produce glucose and galactose.