Biotechnology involves applying biological processes for practical purposes, often using genetic manipulation. It spans diverse applications such as medicine, agriculture, and industry with a particular focus on genetically manipulating microorganisms to produce antibiotics, hormones, and other substances.
Biofuels
Yeast, a unicellular fungus, metabolizes sugar as its primary energy source. During respiration, it generates ethanol and carbon dioxide, releasing energy in the process. The ethanol produced has gained prominence as a biofuel, a renewable alternative to traditional fossil fuels like oil, coal, and gas. Notably, in countries such as Brazil, biofuels are increasingly integrated into the energy mix, gradually displacing petrol in vehicles and other applications.
The production of ethanol involves utilizing plant material as a substrate, providing glucose for fermentation. This material is typically broken down into small particles and combined with yeast, which undergoes anaerobic respiration to produce ethanol. Following fermentation, the liquid is separated from the remaining solids, and any water is extracted, resulting in a concentrated ethanol solution.
In some instances, agricultural waste such as stalks or outer leaves of crops is utilized for ethanol production. However, in other regions, specific crops are cultivated solely for ethanol production purposes. This practice has raised concerns in certain areas where it competes with land resources needed for food crop cultivation, potentially impacting local food security.
Bread Making – Process of Biotechnology
In bread making, biotechnology involves the use of yeast, a single-celled fungus, to ferment sugars and produce carbon dioxide gas, which causes the dough to rise. This fermentation process also generates flavorful compounds, enhancing the taste and aroma of the bread. Biotechnological methods optimize yeast strains and fermentation conditions to improve bread quality, texture, and shelf life.
Ingredients
Flour: Provides the main structure of the bread and contains starch.
Water: Activates the amylases in the flour and facilitates the fermentation process.
Salt: Enhances flavor and regulates yeast activity.
Oil: Adds moisture and can contribute to the bread’s texture.
Yeast: Microorganism responsible for fermentation and carbon dioxide production.
Dough Formation
The flour, water, salt, oil, and yeast are combined to form a dough.
Yeast does not have enzymes for digesting starch, but water activates amylases in the flour, breaking down some starch into sugar.
Water activates amylase to break down the starch into sugar
Fermentation
Yeast ferments the sugar produced by amylases, generating carbon dioxide.
The carbon dioxide creates bubbles in the dough, contributing to its light texture.
The sugar is fermented by the yeast through anaerobic respiration, generating carbon dioxide.
Carbon dioxide leads to the formation of bubbles in the dough, making the break light and airy.
Kneading
The dough is repeatedly folded and stretched (kneaded), either by hand or mechanically.
Kneading develops gluten further and ensures an even distribution of gas bubbles.
Kneading helps the dough to evenly distribute the gas bubbles formed by carbon dioxide production.
Rising
The dough is left to rise at a temperature of about 27°C.
Carbon dioxide bubbles accumulate, causing the dough to double in volume.
Gluten Formation
Gluten, a protein in the flour, gives the dough its sticky and plastic texture.
The gluten helps trap and hold the bubbles of gas produced during fermentation.
Baking
The dough is placed in baking tins or directly on a baking surface.
It goes into an oven at around 200°C.
The heat causes the bubbles to expand more, giving the bread its final light texture.
The yeast is killed, and any remaining alcohol evaporates during baking.
The result is fully risen and baked bread.
During baking, the yeast is killed due to the high temperature of the oven
The ethanol produced during anaerobic respiration is also evaporated
Enzymes
An enzyme is a biological catalyst, typically a protein, that speeds up chemical reactions by lowering the activation energy required for the reaction to occur, without being consumed in the process.
They play a crucial role in various industrial processes, often produced through commercial fermentation using easily available feedstocks like corn-steep liquor or molasses. Fungi, such as Aspergillus, or bacteria, like Bacillus, are commonly employed for enzyme production due to their non-pathogenic nature and lack of antibiotic production.
The fermentation process is similar to that used for penicillin production. If the enzymes are extracellular, they can be filtered from the liquid feedstock, and the enzyme is then extracted. In the case of intracellular enzymes, microorganisms are filtered, crushed, and the enzymes are extracted using water or other solvents. Genetic engineering techniques enable the introduction of new genes into microbes to enhance enzyme properties, such as increased heat stability.
One effective method of enzyme application is immobilization, where enzymes or enzyme-producing microorganisms are held in or on beads or membranes of an insoluble, inert substance like plastic. These immobilized enzymes can be used continuously in columns, avoiding loss during extraction and allowing for continuous processing.
Simple graphic of enzyme immobilisation
Commercial applications of Enzymes
Proteases: Used in washing powders for stain removal (e.g., egg, milk, blood), hair removal from animal hides, cheese manufacturing, and meat tenderization.
Lipases: Serve as flavor enhancers in cheese and are employed in washing powders for removing fatty stains.
Pectinases: Applied in the clarification of fruit juices and to maximize juice extraction.
Amylases: Utilized in the production of glucose from starch.
For instance, Pectinases extracted from fungi like Aspergillus niger find applications in separating juices from fruits like apples. These enzymes break down pectin, the jelly-like substance binding plant cell walls, facilitating the clarification of fruit juice and wine. This breakdown process eliminates cloudy polysaccharides, resulting in clearer juice, and produces sugars, enhancing the sweetness of the juice.
Biological Washing Powders
Stains on clothes often consist of organic molecules like oil from the skin, proteins from blood, and fats and proteins from food. Traditional detergents containing only soap can help remove some of these stains when combined with hot water, but the process may require considerable time and effort, and very high temperatures may be necessary to completely eliminate the stains.
Biological washing powders offer a more efficient solution by incorporating enzymes that resemble digestive enzymes found in the alimentary canal. These enzymes play a key role in breaking down large organic molecules, such as fats and proteins, into smaller, soluble components. This breakdown occurs through enzymatic reactions that mimic the natural digestive processes.
The advantages of using biological washing powders
Lactose-free Milk
Lactose is the sugar naturally present in milk, and it requires the enzyme lactase for proper digestion. Human infants are born with the ability to produce lactase, facilitating the digestion of lactose in their mother’s milk. However, in some populations and regions, many individuals experience a decline in lactase production as they age. This phenomenon is known as lactase non-persistence or lactase deficiency, and it can lead to lactose intolerance.
Lactose intolerance occurs when individuals lack sufficient levels of lactase to effectively break down lactose in the digestive system.
When lactose-intolerant individuals consume dairy products containing lactose, such as milk, cheese, or yogurt, they may experience symptoms like nausea, flatulence, and diarrhea. These symptoms arise because undigested lactose in the digestive tract can cause discomfort and an osmotic imbalance, leading to the characteristic gastrointestinal disturbances.
To make milk lactose-free and suitable for individuals with lactose intolerance, lactase can be added to the milk. Lactase is the enzyme needed to break down lactose into its component sugars, glucose, and galactose, which are easily digestible. This process is often referred to as lactase treatment or lactose hydrolysis.
Addition of Lactase: Lactase enzyme is added to the milk. This can be done in various forms, such as liquid or powder.
Incubation Period: The lactase-treated milk is then allowed to stand or undergo an incubation period. During this time, the added lactase works to hydrolyze or break down the lactose into its simpler sugars.
Lactose Breakdown: The enzymatic action of lactase cleaves the lactose molecule into glucose and galactose. These are monosaccharides that are easily absorbed by the digestive system, even in individuals with lactose intolerance.
Lactose-Free Milk: After the incubation period, the milk is now considered lactose-free, as the lactose has been converted into more easily digestible sugars.
By pre-treating milk with lactase, the resulting lactose-free milk provides a suitable alternative for those who are lactose intolerant, allowing them to enjoy dairy products without experiencing the typical digestive symptoms associated with lactose intolerance.
Formation of Yogurt
An illustrative example of bacterial capabilities in biotechnology is the addition of specific bacteria to milk to produce yogurt. Lactic acid bacteria, such as Lactobacillus species, play a key role in this process by producing lactic acid, which leads to the coagulation of milk proteins and the formation of yogurt.
Graphic of bacteria to produce yogurt
Antibiotics
In the production of antibiotics using microorganisms, the focus is on the complex organic compounds they synthesize rather than their fermentation byproducts. Many of the antibiotics we rely on originate from bacteria or fungi found in soil environments. Actinomycetes, particularly Streptomyces, emerge as significant sources, with Streptomyces producing antibiotics like streptomycin, showcasing their importance in pharmaceuticals.
Role and Origin of Antibiotics
Penicillin, discovered by Sir Alexander Fleming in 1928, remains one of the most renowned antibiotics, sourced from the mould fungus Penicillium. However, modern production involves mutant forms of Penicillium species distinct from those studied by Fleming. These mutants yield various types of penicillin, which undergo chemical modifications in laboratories to enhance efficacy and customize treatment for different diseases. Examples include ‘Ampicillin’, ‘methicillin’, and ‘oxacillin’, illustrating the versatility of this essential antibiotic.
Antibiotic Mechanisms and Types
Antibiotics exhibit diverse mechanisms of action against bacteria, targeting vital cellular processes. Some antibiotics disrupt cell wall synthesis, inhibiting bacterial reproduction and potentially leading to cell lysis. Others interfere with protein synthesis, halting bacterial growth.
Antibiotics that prevent bacterial reproduction are termed bacteriostatic, while those that directly kill bacteria are bactericidal, collectively playing a crucial role in combating bacterial infections with their varied modes of action.
Effects on Human Cells
Antibiotics pose minimal risk to human cells due to the absence of cell walls and distinct protein synthesis machinery in animal cells. This fundamental difference ensures that antibiotics specifically target bacterial cells without harming human cells. However, some individuals may experience side effects like allergic reactions, emphasizing the importance of careful monitoring and consideration of individual responses to antibiotic treatment.
Production of Penicillin
The discovery of penicillin by Alexander Fleming in 1928 marked a pivotal moment in medical history. Fleming observed that certain bacteria in a Petri dish had been killed by a naturally occurring mould called Penicillium. Further investigation revealed that Penicillium secretes a chemical compound that inhibits the growth of certain bacteria, acting as a natural defense mechanism against microbial infections.
In the industrial production of antibiotics like penicillin, giant fermenting tanks with capacities of up to 100,000 liters are utilized. These tanks are filled with a nutrient solution comprising a carbohydrate source, typically sugar such as lactose or corn-steep liquor, which contains amino acids and sugars derived from the manufacture of cornflour and maize starch. Additionally, mineral salts are added to the solution, and the pH is adjusted to a range between 5 and 6, while the temperature is maintained at approximately 26°C. To ensure optimal growth conditions, air is blown through the liquid, and it is continuously stirred.
The use of fermenters offers several advantages in penicillin production.
Fermenters enable the growth of microorganisms in large quantities, ensuring a steady supply of penicillin.
Conditions within the fermenter can be precisely controlled, including temperature, pH, oxygen levels, and nutrient availability.
Precise control of these factors ensures optimal growth and productivity of the microorganisms.
Higher yields of penicillin are achieved due to the optimized growth conditions provided by fermenters.
The process begins by seeding the nutrient liquid with a culture of the appropriate microorganism, such as Penicillium fungus, which is then allowed to grow for a day or two. It is crucial to maintain sterile conditions throughout this process to prevent contamination by foreign bacteria or fungi, which could disrupt the production process. As the microorganisms consume the nutrients in the solution, they begin to secrete antibiotics into the medium.
Once the antibiotic production reaches an optimal level, the nutrient fluid containing the antibiotic is filtered off from the fermenting tank. The antibiotic is then extracted from the solution using methods such as crystallization or other purification techniques. This extraction process ensures that the antibiotic is isolated and purified, ready for formulation into various dosage forms for medical use. Overall, industrial fermentation plays a crucial role in the large-scale production of antibiotics, providing an efficient and controlled environment for microbial growth and antibiotic synthesis.
In Simpler Terms:
Imagine penicillin as a superhero protecting us from harmful bacteria like villains. Just like how superheroes need a special place to train and grow stronger, penicillin is made in a special place called a fermenter. This fermenter is like a high-tech gym where tiny living organisms, like bacteria and fungi, are trained to make penicillin. Scientists are like trainers, carefully controlling everything in the fermenter, like temperature and food, to help these tiny superheroes grow and produce lots of penicillin. So, just like how a superhero saves the day, penicillin fights off bad bacteria and helps keep us healthy!
