Biotechnology
Author : Daniella Green | Published On : 07 Dec 2023
17.2.3 Describe methods of production of different fermentation products (yogurt, bread, cheese and alcohol);
Fermentation is a natural process that can be used in a number of ways for wide variety of food products. As a fermented food, yogurt is the result of the bacterial transformation of milk.
Fermented foods are those in which microorganisms have transformed relatively complex substances into simpler ones. This simple process can change the food characteristics completely, turning grape juice into wine or milk into yogurt.
Yogurt
Yogurt is a popular fermented dairy product produced by lactic acid bacteria, including Lactobacillus delbruekii sp. bulgaricus and Streptococcus thermophiles. They do not compete for the same nutrients. Both help each other grow until they reach a stable balance. Together, they transform the lactose naturally present in milk into lactic acid, creating yogurt.
Bread
Bread is the commonest type of fermented cereal product. Wheat dough is fermented by yeast along with some lactic acid bacteria.
Yeast, typically Saccharomyces cerevisiae, is used in bread production.
Process
Mix flour, water, yeast, and other ingredients to form a dough.
Allow the dough to rise, which is called fermentation, as the yeast consumes sugars and produces carbon dioxide gas.
Shape the dough into the desired form.
Bake the bread, during which the carbon dioxide expands the dough, causing it to rise and form air pockets.
Bread recipes can vary based on the type of flour, fermentation time, and additional ingredients, resulting in a wide range of bread types.
Cheese
The cheese production is carried out from lactic acid fermentation of milk. By the enzymatic activity of rennin the coagulation of milk protein and formation of curd will take place. After the curd is formed it is heated and pressed to remove the watery part of the milk, salted and then ripened.
The organisms responsible for the manufacturing of cheese are Lactobacillus lactis, Propionibacterium sps. and Penicillium sps.
Casein- the protein in milk which forms curds when coagulated with rennet.
Chymosin or rennin is a protease found in rennet.
Rennin or chymosin, is a protein digesting enzymes that digest milk protein cassein.
Process
- Curdle milk using acid (for fresh cheeses) or enzymes (rennet) for coagulation.
- Cut the curd into small pieces and drain off the whey.
- Press the curd into molds to remove excess whey and shape the cheese.
There are numerous cheese types, each with its unique production methods and microorganisms, leading to distinct textures and flavors.
4. Alcohol (Beer and Wine):
Yeast, primarily Saccharomyces cerevisiae, is used for alcohol fermentation in both beer and wine production.
Process
Beer is produced from cereal grains which have been malted, dried and ground into fine powder. Fermentation of the powder is done by yeast. This process breaks the glucose present in powder into pyruvic acid and then into ethanol. Grapes can be directly fermented by yeasts to wine.
Genetic Engineering
Genetic engineering or recombinant DNA technology involves the artificial synthesis, modification, removal, addition and repair of the genetic material (DNA).
Genetic engineering developed in the mid-1970s when it became possible to cut DNA and to transfer particular pieces of DNA from one type of organism into another. As a result, the characteristics of the host organism could be changed.
If host organism is a microorganism, such as a bacterium, the transferred DNA is multiplied many times as the microorganism multiplies. Consequently, it is possible to obtain millions of copies of a specific DNA inside a bacterial cell.
Genetically modified organism (GMO)
In practice, DNA contains the genes to build certain proteins, by changing the DNA sequence, attempts are on to design a new gene for a cell/organism resulting in a different protein and also making a cell capable of performing the desired functions. The resultant organism is broadly referred as genetically modified organism (GMO).
History of GMO Development
Paul Berg in 1972 produced the first recombinant DNA molecules. With advancement, it is nowpossible to manipulate, remove, and add genes to a variety of different organisms to induce a range ofdifferent traits.
Herbert Boyer and Stanley Cohen in 1973 created the first genetically modified bacteria followed by a number of remarkable achievements in this field. Some of the major achievements of genetic engineering are:
1974: GM mice was created
1976: Commercialization of the technology after which producing and selling genetically modified foods and medicines began.
1982: The first commercial development of GMOs (insulin-producing bacteria
1994: began to sell genetically modified food
1997: The first successfully cloned large mammal (sheep) named Dolly was developed
2003: began to sell GMOs as pets (Glofish )
17.3.1 Describe objectives of genetic engineering (for high yield of products, for production of organisms with desired characteristics, for gene therapy);
Genetic engineering is a powerful and versatile field of biotechnology that encompasses a wide range of objectives, all of which involve manipulating the genetic material of organisms.
High yield:
Genetic engineering can be used to enhance the production of valuable products, such as food, pharmaceuticals, and industrial chemicals. Some specific objectives within this category include:
1. Crop Improvement: Genetic engineering is employed to develop genetically modified (GM) crops with traits like increased yield, resistance to pests, tolerance to adverse environmental conditions, and improved nutritional content. This helps ensure a stable and sufficient food supply for a growing global population.
Genetic modification of crops has substantially focused on improving traits for desirable outcomes. It has resulted in the development of crops with enhanced yields, quality, and tolerance to biotic and abiotic stresses.
2. Biopharmaceuticals: Genetic engineering is used to produce therapeutic proteins, vaccines, and other pharmaceuticals in genetically modified organisms, such as bacteria, yeast, and mammalian cells, for the efficient and cost-effective production of medicines.
3. Industrial Fermentation: Microorganisms can be genetically modified to produce valuable industrial chemicals, biofuels, and enzymes. This is essential for sustainable and eco-friendly manufacturing processes.
Production of organisms with desired characteristics:
Genetic engineering can be employed to create organisms with specific traits, whether for scientific research, agriculture, or other purposes.
Transgenic organisms are those with genes from other species. Genetic engineering is used to create transgenic animals and plants with characteristics not naturally found in the species. This can include traits like disease resistance, herbicide tolerance, and faster growth rates. Genetically modified foods are obtained from genetically modified organisms, or transgenic crops. Genetic engineering has resulted in a number of improved traits in transgenic plants by genetic alteration. Some of these traits are:
( Production of extra nutrients in the food ( Increased growth rate ( Disease resistance and herbicide resistance ( Better taste ( Increased shelf life etc. ( lesser requirement for water
The first genetically modified whole food crop was tomato (called Flavr Savr), which was made more rot-resistant.
Gene Therapy:
Gene therapy aims to treat or prevent genetic disorders by introducing, repairing, or replacing faulty genes in human patients. The main objectives of gene therapy include:
Treating Genetic Disorders: Gene therapy can be used to correct genetic mutations responsible for inherited diseases. Genetic engineering may help alleviate the symptoms of genetic disorders, improve the quality of life for affected individuals, and potentially extend their lifespan.
Enhancing Immunity: In some cases, gene therapy can be used to bolster the immune system's ability to fight cancer or infectious diseases by modifying the patient's own immune cells.
17.3.2 Describe how a gene is transplanted;
Following are the basic steps in genetic engineering for gene transplantation
Isolation of the gene of interest
Insertion of the gene into a vector
Transfer of recombinant DNA into host organism
Growth of the GMO
Expression of the gene
17.3.3 # describe major achievements of genetic engineering with reference to improvement in agricultural crops (herbicide resistance, virus resistance and insect resistance);
Genetic engineering has achieved significant advancements in improving agricultural crops, particularly in enhancing resistance to herbicides, viruses, and insects. These achievements have had a profound impact on agriculture, increasing crop yields, reducing the use of chemical pesticides, and contributing to global food security.
Herbicide Resistance:
Genetic engineering has enabled the development of crops resistant to specific herbicides. The most prominent example is glyphosate-resistant crops, often referred to as Roundup Ready crops. These crops have been engineered to tolerate the herbicide glyphosate, which is a broad-spectrum herbicide. Major achievements in herbicide resistance include:
Glyphosate-Resistant Crops: Crops like soybeans, corn, cotton, and canola have been modified to withstand glyphosate, allowing farmers to apply the herbicide to eliminate weeds without harming the crop. This technology simplifies weed control, reduces labor and the need for alternative herbicides, and increases crop yields.
Examples of GMO herbicide-tolerant crops include canola and soybean varieties or corn hybrids tolerant to glyphosate and glufosinate herbicides.
Virus Resistance:
Genetic engineering has been used to develop crops that are resistant to devastating plant viruses, protecting them from infection and reducing crop losses. Some notable achievements include:
Papaya Ringspot Virus-Resistant Papaya: In the 1990s, the papaya industry in Hawaii was threatened by the Papaya Ringspot Virus (PRSV). Genetic engineering was used to develop PRSV-resistant papaya varieties, which saved the papaya industry from collapse.
Plum Pox Virus-Resistant Plum and Tomato: Genetic engineering has been used to create plum and tomato varieties resistant to the Plum Pox Virus (PPV), a highly destructive pathogen. This technology has the potential to protect fruit crops from significant economic losses.
Examples: papayas resistant to ringspot virus and squash resistant to zucchini yellow mosaic and watermelon mosaic viruses.
Insect Resistance:
Genetic engineering has enabled the development of crops that produce insecticidal proteins, reducing the need for chemical insecticides and enhancing crop protection. Major achievements in insect resistance include:
Bt (Bacillus thuringiensis) Crops: Bt crops, such as Bt cotton and Bt corn, produce a protein derived from the bacterium Bacillus thuringiensis. This protein is toxic to certain insect pests, including caterpillars and beetles. By incorporating Bt genes into crops, farmers can reduce the damage caused by these pests while minimizing the use of chemical pesticides.
Pink Bollworm Control in Bt Cotton: Bt cotton has been particularly successful in reducing pink bollworm infestations in cotton crops, leading to increased yields and reduced pesticide use.
17.3.4 Describe major achievements of genetic engineering in health and medicine, e.g. production of insulin, human growth hormone, thymosin, beta-endorphin, vaccine against foot-and-mouth disease, interferon and urokinase and cloning
