Fungal Lactase
The predictable improver

Lactase is an enzyme in the small intestine that digests lactose (the naturally occurring sugar in milk). Normally lactase breaks lactose down into a form that can be easily absorbed by the blood. Milk, ice cream, yogurt and other dairy products have varying levels of lactose, which affect how much lactase is required for proper digestion.

Lactase (LCT), a member of the ß-galactosidase family of enzyme, is involved in the hydrolysis of the disaccharide lactose into constituent galactose and glucose monomers. In humans, lactase is present predominantly along the brush border membrane of the differentiated enterocytes lining the villi of the small intestine. Lactase is essential for digestive hydrolysis of lactose in milk. Deficiency of the enzyme causes lactose intolerance; most humans become lactose intolerant as adults. Lactase is the enzyme in the small intestine that digests lactose (the naturally occurring sugar in milk).

Lactase has an optimum temperature of about 48 °C for its activity and an optimum pH of 6.5. In humans, the gene is localised on the second chromosome (2q21). Bacterial and Archaea lactase lack a membrane binding domain and free float around the cell, these also tend to be more general ß-galactosidase that will cleave more then just lactose.

A few children and many people after childhood do not produce sufficient lactase, resulting in impaired ability to digest milk. These people are lactose intolerant and often suffer from symptoms including cramps, gas, and diarrhea. Lactose intolerance is best diagnosed by a doctor, However, a reasonably reliable home test for lactose intolerance is to drink two 8-ounce glasses of milk on an empty stomach and note any gastrointestinal symptoms that develop over the next four hours; repeat the test on another day using several ounces of cheese (which does not contain much lactose). If symptoms result from milk but not cheese, then the person probably has lactose intolerance. If symptoms occur with both milk and cheese, the person may be allergic to dairy. In case of lactose intolerance there is not enough lactase to digest the amount of lactose consumed, water is retained in the bowel, which, results in bloating and diarrhea. Bacteria ferment lactose that passes into the large intestine. This produces carbon dioxide, hydrogen and methane. This may lead to bloating, cramping and gas.

Mode of Action:

Fungal lactase is an enzyme manufactured by the controlled fermentation of Aspergillus oryzae followed by sophisticated recovery steps to yield enzyme fit to be used in pharmaceutical applications.

Fungal Lactase is characterized by its ability to hydrolyze lactose over a wide range of temperature and pH. The lactase catalyses the hydrolysis of the lactose beta-D-galactoside linkage liberating one mole of D-glucose and one mole of D-galactose. The average duration of time between oral dosing and germination is four hours. After germination, Lactic Acid Bacillus is metabolically active in the intestines, producing lactic acid.

Industrial Uses of Lactase:

Lactase produced commercially can be extracted both from yeasts such as Kluyveromyces fragilis and Kluyveromyces lactis and from fungi, such as Aspergillus niger and Aspergillus oryzae. Its primary commercial use is to break down lactose in milk to make it suitable for people with lactose intolerance. Lactase is also used in the manufacture of ice cream. Because glucose and galactose are sweeter than lactose, lactase produces a more pleasant taste. Lactose also crystallises at the low temperatures of ice cream; however, its constituent products stay liquid and contribute to a smoother texture. Lactase is used in the conversion of whey into syrup.

Lactose may be hydrolysed by lactase, a b-galactosidase.

Lactases are now used in the production of ice cream and sweetened flavoured and condensed milks. When added to milk or liquid whey (2000 U kg-1) and left for about a day at 5°C about 50% of the lactose is hydrolysed, giving a sweeter product which will not crystallise if condensed or frozen. This method enables otherwise-wasted whey to replace some or all of the skim milk powder used in traditional ice cream recipes. It also improves the 'scoopability' and creaminess of the product. Smaller amounts of lactase may be added to long-life sterilised milk to produce a relatively inexpensive lactose-reduced product (e.g. 20 U kg-1, 20°C, 1 month of storage). Generally, however, lactase usage has not reached its full potential, as present enzymes are relatively expensive and can only be used at low temperatures.