For many thousands of years, man has used naturally occurring micro-organisms - bacteria, yeasts and moulds - and the enzymes they produce to make foods such as bread, cheese, beer and wine. For example in bread-making the enzyme, amylase, is used to break down flour into soluble sugars, which are transformed by yeast into alcohol and carbon dioxide. This makes the bread rise.
Today, enzymes are used for an increasing range of applications: bakery, cheese making, starch processing and production of fruit juices and other drinks. Here, they can improve texture, appearance and nutritional value, and may generate desirable flavours and aromas. Currently-used food enzymes sometimes originate in animals and plants (for example, a starch-digesting enzyme, amylase, can be obtained from germinating barley seeds) but most come from a range of beneficial micro-organisms.
In food production, enzymes have a number of advantages:
They are welcomed as alternatives to traditional chemical-based technology, and can replace synthetic chemicals in many processes. This can allow real advances in the environmental performance of production processes, through lower energy consumption and biodegradability.
They are more specific in their action than synthetic chemicals. Processes which use enzymes therefore have fewer side reactions and waste by-products, giving higher quality products and reducing the likelihood of pollution.
They allow some processes to be carried out which would otherwise be impossible. An example is the production of clear apple juice concentrate, which relies on the use of the enzyme, pectinase.
Where enzymes are produced from micro-organisms (the main types include species of Bacillus, Aspergillus, Streptomyces and Kluyveromyces), these are grown by fermentation in large vats or fermenters with capacities of up to 150,000 litres; here, temperature, nutrients and air supplies are adjusted to suit their optimal development. As in other parts of the food chain, strict rules of hygiene are followed. When the process is complete, the fermenter contains a broth which includes enzymes, nutrients and microbes. This is purified by passing it through a series of filters to remove impurities and extract the enzyme.
Making improved products
Since the early 1980s, companies which produce enzymes have been using genetic engineering techniques to improve production efficiency and quality and to develop new products. There are clear advantages here for both industry and consumers, with major improvements in enzyme production giving better products and processes. However, progress is being slowed down because the debate on some other, more controversial applications of biotechnology - such as genetic engineering in animals - is continuing throughout Europe.
At present, modern biotechnology can be used to give a range of advances in enzymatic production technology: the improved productivity and cost-effectiveness in existing processes. By producing enzymes more efficiently, the amount of raw materials, energy and water needed to make a product can be reduced by as much as one-half by changing from a traditional strain of microbe to a genetically modified one. Companies can tailor their enzymes more precisely to customer demands for products with specific properties. Manufacturers can supply enzymes which otherwise could not be produced in large enough quantities, giving the consumer access to a wider variety of products. An example is the amylase-based product which makes bread stay fresh for longer.
The discovery that genes are made up of DNA and can be isolated, copied and manipulated has led to a new era of modern biotechnology. New Zealand has many applications for modern biotechnologies.
Humans have been manipulating living things for thousands of years. Examples of early biotechnologies include domesticating plants and animals and then selectively breeding them for specific characteristics.
Modern biotechnologies involve making useful products from whole organisms or parts of organisms, such as molecules, cells, tissues and organs. Recent developments in biotechnology include genetically modified plants and animals, cell therapies and nanotechnology. These products are not in everyday use but may be of benefit to us in the future.
Applications in biotechnology
Key applications of biotechnology include:
DNA profiling – Get information sheet: DNA profiling
DNA cloning – Get information sheet: DNA cloning transgenesis genome analysis stem cells and tissue engineering
Meeting human needs and demands
Biotechnologies have an important role in meeting human needs and demands in medicine, agriculture, forensics,bioremediation, biocontrol and biosecurity.
Gene modification or transgenesis are used to produce therapeutic human proteins in cells or whole organisms. The cell or organism used depends upon how large and complex the protein is. For example, human insulin, a small protein used to treat diabetes, is made in genetically engineered bacteria, whereas large, more complex proteins like hormones or antibodies are made in mammalian cells or transgenic animals.
Antibiotics and vaccines are products of microorganisms that are used to treat disease. Modern biotechnologies involve manipulating vaccines so they are more effective or can be delivered by different routes.
Gene therapy technologies are being developed to treat diseases like cancer, Parkinson’s disease and cystic fibrosis. Gene therapy is being used as a way to target and kill cancer cells with fewer side effects.
Plants and animals can be improved by selectively breeding for particular traits or by genetic modification. Beneficial traits can be identified visually or by DNA profiling. For example, farmers may want plants with herbicide or insect resistance, tolerance to different growing environments or improved storage, or they may want livestock with better meat and wool or resistance to disease.
DNA profiling is used in forensic analysis to identify DNA samples at a crime scene or to determine parentage.
Organisms or parts of organisms can be used to clean up pollution in soil, water or air. Bioremediation has been suggested as an effective way of removing the toxin DDT from the soil. Biocontrol is when one organism is used to control the levels of another.