General information about enzymes
What is an enzyme?
An enzyme is not a chemical but a BIOCATALYST.
This is not a chemical but a NATURAL PROTEIN composed of one or
more chains of amino acids in a specific order.
Amino-acid sequence is determined by the base sequence of
nucleotides in the DNA coding for the protein.
Enzymes are present in all cells of living organisms and catalyse
They are produced at large scale starting from micro-organisms such as
bacterial, moulds or yeasts grown in culture medium.
Enzymes have specificity for one substrate that they change in products
with modified properties.
After the reaction, the enzyme is not modified and can catalyse again.
Enzymes have specific biochemical properties such as optimal pH and
Industrial production of enzymes
Origin of industrial enzymes:
Enzymes can be produced starting from various sources:
plants (ex: Carica papaya for papaïn for beer chill proofing)
bacteria (ex: Bacillus amyloliquefaciens for protease in baking)
moulds (ex: Aspergillus niger for pectinases for fruit processing)
yeasts (ex: Saccharomyces cerevisiae for invertase in confectionary)
Industrial production of enzymes is made in submerged or solid state culture in large vessel containing the pure strain of selected micro-organism, nutrients and a substrate inducing the production by the micro-organism of enzymes necessary for its own metabolism.
At the end of the culture, exocellular enzymes are recovered, concentrated and stabilised with a carrier such as glycerol (for liquid products) or maltodextrins (for micro-granulate products), decreasing water activity for better enzyme stability and less microbiological contamination.
Main applications of enzymes are in biological detergent, starch, paper industry, baking, brewing, fruit juices and dairy.
Biochemical properties of enzymes
Main enzymatic reactions are hydrolysis, beta-elimination, oxidation, or isomerisation.
Examples of hydrolysis:
sucrose ————–> fructose + glucose starch ————–> dextrins
-Optimal and stability of enzyme activity are pH and temperature dependent.
-If the pH in application is very far from enzyme optimal, it must be adjusted.
-Fortunately, optimal pH of pectinases from Aspergillus niger must not be adjusted
for processing fruit.
Temperature of the process must be controlled during all stages for being close to take advantage of optimal enzyme activity and to avoid the destruction of the enzyme above its optimal temperature.
Dosage of pectinases is very low (ex. 100 g of pectinases per ton of fruit). Dilution of enzyme in water is required to enlarge the volume for a good mixing with the fruit pulp.
-Reaction time is proportional to enzyme dosage (ex: reaction time is half if the dosage is doubled).
-Temperature increase activates the enzyme activity (ex: an increase of 10°C doubles the enzyme activity, or dosage can be reduced by 2 for the same effect).
Legislation concerning micro-organisms used for enzyme production is country dependent
Electrophoresis of self-cloned enzyme Electrophoresis of classical enzyme