The Economic Impact of the Use of Enzymes in Industry.

The significance of these properties is that enzymes will only react in a specific way with a specific reactant. This is beneficial as only the desired reaction will be catalysed, with no side-reactions occurring. Therefore there are fewer by-products, so the process is more efficient as material costs are reduced. Additionally, the resulting products of the reaction are more refined and do not require purification which reduces costs and possible environmental impact. The fact that enzymes are stereospecific means that they can catalyse reactions that would be very difficult with a chemical catalyst; for example the conversion of glucose to fructose.

Enzymes occur naturally in microorganisms, so they can be fermented and produced in huge numbers.  Enzymes also have moderate requirements; a warm temperature and a neutral pH which negates the need to maintain harsh environments needed for chemically catalysed reactions. Chemical reactions often require high temperatures and/or high pressures to increase the number of collisions. Enzymes do not typically need these criteria, so costs are reduced as energy costs are lessened and also capital costs are reduced as there is less corrosion and unwanted side reactions from the use of enzymes as opposed to chemical catalysts. For example, the Haber Process produces ammonia by combining hydrogen and nitrogen. However, it requires pressure of around 200 atmospheres, and a temperature of around 500 degrees Celsius. In comparison, nitrogen fixing bacteria can produce ammonia by combining the two gases from the surrounding air using ATP, at room temperature and normal pressure.

For example, in the pulp and paper industry enzymes can be used to separate cellulose fibres and make bleaching unnecessary. To make paper, cellulose fibres must be separated from a wood fibre called lignin. Normally this requires the use of mechanical processing or adding strong chemicals. However, lignin-degrading fungi produces cellulase and xylanase enzymes can be used to break down the lignin instead, saving energy and money. Lignin fibres are usually coloured, which is why paper needs to be bleached, normally using chlorine compounds under high pressure. Enzymes can be used to remove the fine surface fibres which cause discolouration, which means that the bleaching process can be reduced or completely avoided.

Another useful application of enzymes in industry is in textiles. To start with, bacterial enzymes can be used to separate flax fibres from flax plants in a process called retting. Traditionally, retting requires a large volume of water and a high level of energy, which would both increase costs. Enzymes are also used to remove hydrogen peroxide from fabrics. Hydrogen Peroxide is left on the surface of cotton after it has been bleached. Catalase can be used to break down hydrogen peroxide to prevent it reacting with other dyes that are applied to the cotton.  Detergents provide another use for enzymes in the textile industry. Enzymes such as protease and amylase are used to remove stains caused by organic matter from clothing; for example blood, sweat, food etc. They are more effective than non biological detergents, as these require high temperatures and vigorous shaking to remove dirt. Both of these require more energy for the washing machine, which equates to a higher cost.

Enzymes may also be used in the fuel industry. Cellulases are used to convert cellulose fibres into sugars. The sugars are then fermented into ethanol by microorganisms. This provides a renewable source of fuel, and as most current fuels are non renewable, their price will rise making bio fuels produced from enzymes a more economic choice.  This is made more efficient by a new process called Simultaneous Saccharification and Fermentation. Cellulase enzymes and fermentation microorganisms are combined in a single reaction mixture to produce ethanol more quickly.

The disadvantages of enzymes include the high cost of their isolation and purification discourages their use, especially if there are alternatives in place. Furthermore, enzymes are relatively unstable when removed from their natural environment (i.e. prone to denaturing at high temperatures or extreme pH levels.) Denaturing from heat occurs when high temperatures cause the weak bonds that stabilize a protein’s secondary and tertiary structure to break, causing the enzyme to change shape and become unable to bind with its substrate. Denaturing from pH change happens because the change in pH alters the ionization of the constituent amino acids. Again, this causes bonds to break and the shape to change.  

 Enzymes often need to be isolated and purified from their microorganism, as fermenting whole cells has several disadvantages. Aeration and mixing is energy consuming, and fermenters are expensive to build and maintain. Additionally, the products are more impure and there are more waste products which need to be disposed of, both of which require energy (and therefore higher costs) to rectify as opposed to purified enzymes. Enzymes are isolated to make them more stable and easily recoverable. This is done by fermenting the respective microorganism, and then excreting and purifying the enzyme. However purification and isolation are still both expensive processes.

However once the initial costs of converting an industry to enzymes from previously using chemical catalysts are paid, enzymes can provide a much cheaper and efficient alternative. The economy has the potential to benefit hugely in the long term, as higher yields can be produced in industry, and at home energy costs can be greatly reduced.