The biological molecules that regulate various metabolic activities inside the living body are termed as enzymes. They are proteinaceous in nature. Several enzymes produced by microbes are used in food industry and are of great concern. They include; amylase, Invertase, glucose oxidase, protease, pectinase, etc.
Amylases are enzymes that hydrolyze starch. The amylases include alpha-amylase, beta- amylase and amyloglucosidase. Most of the amyloglucosidase are provided by the grain malt and are used for industrial purpose. Bacteria and molds are mainly responsible for the production of most of the amylases.
Rhizopus delemar, Mucor rouxii are some of the molds commonly involved in amylase production. A starchy grain mash is prepared and the molds are made to grow on it. These acts upon them molds and saccharify the starch in them. This is termed as the amyloid process. This process is mainly employed for the production of mash in the alcohol fermentation process.
Soy sauce which is rich in amylase uses Aspergillus oryzae as a starter. Aspergillus oryzae is also used for amylase production from wheat or rice bran. The amylase is extracted from the mycelium and purified by precipitation and washing.
Bacillus subtilis is one of the major bacteria involved in amylase production. The mash used for amylase by Bacillus subtilis contains soluble or hydrolyzed starch, ammonium salts and buffers. Some others contain peanut cake, soybean cake, or casein as a source of nitrogen and various mineral salts. Bacterial amylase can be purified and concentrated by dialysis, condensation and fractional precipitation.
The industrial use of fungal amylase includes the removal of starch from fruit extracts, to clarify Turbidity in wine, convert acid-modified starches to sweet syrups, etc. Bacterial amylases are used to clarify beer, used to prevent thickening of chocolate syrups, etc.
Invertases are also microbial enzymes that are used for the hydrolysis of sucrose to glucose and fructose. Saccharomycyes cerevisiae are the special strains that are used for the industrial production of Invertase. The Invertase extracted from yeast cells may be dried with sugar or the enzyme may be purified by dialysis, ultra filtration, adsorption and elution. Invertase finds uses mostly in confectionery to make invert sugars for ice cream preparation. It is also employed in the production of soft- centered chocolate coated candies. It is also used in the preparation of artificial honey.
Proteolytic enzymes are those which are commonly used in jellies. Pectin is an important enzyme which helps in jelly formation along with sugar and acid. A mixture of proteolytic enzymes is called pectinase. Bacteria such as Clostridia species, molds like Aspergillus, Penicillium, etc helps in pectinase production. Pectinase are also used in clarification of wines, syrups, vinegar, etc.
Proteases are enzymes which are of two kinds. Proteinases and peptidases are two of them. Microbes mostly produce proteases. Bacillus subtilis are main protease producers. The medium used for production contain carbohydrates, proteins and mineral salts. The enzyme mixture also contains small amounts of amylases. Aspergillus oryzae are the main molds that produce protease. The proteases from bacteria are used for the liberation of fish oil from fish liver, tenderization of meat, improving the dough consistency, etc.
Aspergillus oryzae produces glucose oxidase and used for removing glucose from egg white, extending the shelf life of canned soft drinks, etc.
Cellulase, lipase, dextransucrase, lactase, catalase, etc are also microbial enzymes that are used in various industries like baking, corn milling industry, etc.