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22.5B: Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt - Biology

22.5B: Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt - Biology


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Some of the earliest biotechnology used prokaryotes for the production of food products such as cheese, bread, wine, beer, and yogurt.

Learning Objectives

  • Discuss the origins of food biotechnology as indicated by the production of cheese, bread, wine, beer, and yogurt

Key Points

  • Prokaryotes and other microbes are beneficial to some food production by transforming textures, providing flavors, producing ethanol, and providing protection from unwanted microbes.
  • Bacteria breakdown proteins and fats into a complex mix of amino acids, amines, and fatty acids; this processing alters the food product.
  • Many food production processes rely on the fermentation of prokaryotes and other microbes to produce the desired flavors; in the case of beer and wine, they also affect the desired amount of ethanol.

Key Terms

  • fermentation: an anaerobic biochemical reaction, in yeast, for example, in which enzymes catalyze the conversion of sugars to alcohol or acetic acid with the evolution of carbon dioxide
  • biotechnology: the use of living organisms (especially microorganisms) in industrial, agricultural, medical, and other technological applications

Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt

According to the United Nations Convention on Biological Diversity, biotechnology is “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use. ” The concept of “specific use” involves some sort of commercial application. Genetic engineering, artificial selection, antibiotic production, and cell culture are current topics of study in biotechnology. However, humans have used prokaryotes before the term biotechnology was even coined. Some of the products are as simple as cheese, bread, wine, beer, and yogurt,which employ both bacteria and other microbes, such as yeast.

Cheese production began around 4,000–7,000 years ago when humans began to breed animals and process their milk. Fermentation, in this case, preserves nutrients because milk will spoil relatively quickly, but when processed as cheese, it is more stable. A required step in cheese-making is separating the milk into solid curds and liquid whey. This usually is done by acidifying the milk and adding rennet. The acidification can be accomplished directly by the addition of an acid like vinegar, but usually starter bacteria are employed instead. These starter bacteria convert milk sugars into lactic acid. The same bacteria (and the enzymes they produce) also play a large role in the eventual flavor of aged cheeses. Most cheeses are made with starter bacteria from the Lactococci, Lactobacilli, or Streptococci families. As a cheese ages, microbes and enzymes transform texture and intensify flavor. This transformation is largely a result of the breakdown of casein proteins and milkfat into a complex mix of amino acids, amines, and fatty acids. Some cheeses have additional bacteria or molds intentionally introduced before or during aging. In traditional cheesemaking, these microbes might already be present in the aging room; they are simply allowed to settle and grow on the stored cheeses. More often today, prepared cultures are used, giving more consistent results and putting fewer constraints on the environment where the cheese ages.

Records of brewing beer date back about 6,000 years to the Sumerians. Evidence indicates that the Sumerians discovered fermentation by chance. Wine has been produced for about 4,500 years. The production of beer and wine use microbes, including both yeast and bacteria, to produce ethanol during fermentation as well as provide flavor to the beverage. Similarly, bread is one of the oldest prepared foods. Bread-making also uses the fermentation of yeast and some bacteria for leavening and flavor. Additionally, evidence suggests that cultured milk products, such as yogurt, have existed for at least 4,000 years. These products use prokaryotes (as with cheese) to provide flavor and to protect the food product from other unwanted microbes.


How has biotechnology been used in the past?

1919: The word &ldquobiotechnology&rdquo is first used by a Hungarian agricultural engineer. Pfizer, which had made fortunes using fermenting processes to produce citric acid in the 1920s, turned its attention to penicillin.

Subsequently, question is, how long has biotechnology been used in food production? Biotechnology has a long history of use in food production and processing. For ten thousand years fermentation, a form of biotechnology, has been used to produce wine, beer and bread. Selective breeding of animals such as horses and dogs has been going on for centuries.

Keeping this in consideration, how long have people been using processes that are considered forms of biotechnology?

Biotechnology involves using living organisms in the production of food and medicine. It dates back several thousand years to when people inadvertently discovered the usefulness of one-celled organisms like yeasts and bacteria. The ancient Egyptians, for example, used yeast to brew beer and to bake bread.

What are the products of traditional biotechnology?

TRADITIONAL BIOTECH CUISINES Bread, yogurt, cheese, wine, and beer are produced by fermentation. from carbon dioxide production. The trapped carbon dioxide causes the bread to rise. food products were produced initially by accident.


Biotechnology - Biology bibliographies - in Harvard style

Your Bibliography: Bio.org. 2016. What is Biotechnology? | BIO. [online] Available at: <https://www.bio.org/articles/what-biotechnology> [Accessed 13 May 2016].

Defining Ethics

2015 - Boundless

In-text: (Defining Ethics, 2015)

Your Bibliography: Boundless, 2015. Defining Ethics. [online] 9. Available at: <https://www.boundless.com/management/textbooks/boundless-management-textbook/ethics-in-business-13/ethics-an-overview-95/defining-ethics-446-8310/> [Accessed 16 May 2016].

Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt

2016 - Boundless

In-text: (Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt, 2016)

Your Bibliography: Boundless, 2016. Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt. [online] 6. Available at: <https://www.boundless.com/biology/textbooks/boundless-biology-textbook/prokaryotes-bacteria-and-archaea-22/beneficial-prokaryotes-144/early-biotechnology-cheese-bread-wine-beer-and-yogurt-571-11785/> [Accessed 16 May 2016].

Moore, A.

Antibiotics in biotechnology

In-text: (Moore, 2013)

Your Bibliography: Moore, A., 2013. Antibiotics in biotechnology. [online] prezi.com. Available at: <https://prezi.com/3gc0gy0huoph/antibiotics-in-biotechnology/> [Accessed 16 May 2016].

Antibiotic resistance — what is it and why is it a problem?

In-text: (Antibiotic resistance — what is it and why is it a problem?, 2013)


22.5 Beneficial Prokaryotes

In this section, you will explore the following questions:

  • What is the need for nitrogen fixation and how is it accomplished?
  • What are examples of foods for which prokaryotes are used in processing?
  • What is bioremediation and how do prokaryotes play a role in this process?

Connection for AP ® Courses

We commonly think of pathogens when we think of prokaryotes, focusing on their relationship with disease. However, most prokaryotes do not cause disease and they play a wide range of other roles in ecosystems. Nitrogen needed to synthesize proteins and nucleic acids is often the most limiting element in ecosystems and bacteria are able to “fix” nitrogen into forms that can be used by eukaryotes. Microbes also are used to remove pollutants from environments, a process called bioremediation. Microbes that call us home are necessary for our survival. They help us digest our food, produce crucial nutrients, protect us from pathogenic microbes, and help train our immune system to function correctly. In addition, without prokaryotes we wouldn’t have cheese, bread, wine, beer, and yogurt.

Teacher Support

Emphasize for students that although the best-known prokaryotes tend to be those that cause illness in humans, these pathogens represent only a small fraction of prokaryotic species. Many others have positive interactions with humans, and some play important roles in agriculture and industry. As students work through the chapter material, invite them to identify at least two ways prokaryotes have affected them in the day. You may wish to invite small groups to research additional roles of prokaryotes in the food industry, bioremediation, and the production of vitamins, antibiotics, hormones, and other products. Create a running list of positive effects and beneficial impacts of prokaryotes on human lives, and post it in the classroom for everyone’s reference.

Information presented and the examples highlighted in the section support concepts outlined in Big Idea 4 of the AP ® Biology Curriculum Framework. The AP ® Learning Objectives listed in the Curriculum Framework provide a transparent foundation for the AP ® Biology course, an inquiry-based laboratory experience, instructional activities, and AP ® exam questions. A learning objective merges required content with one or more of the seven science practices.

Big Idea 4 Biological systems interact, and these systems and their interactions possess complex properties.
Enduring Understanding 4.B Competition and cooperation are important aspects of biological systems.
Essential Knowledge 4.B.2 Interactions among prokaryotes and between prokaryotes and other organisms lead to increased efficiency and utilization of energy and matter.
Science Practice 1.4 The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively.
Learning Objective 4.18 The student is able to use representations and models to analyze how cooperative interactions within organisms promote efficiency in the use of energy and matter.

The Science Practice Challenge Questions contain additional test questions for this section that will help you prepare for the AP exam. These questions address the following standards:
[APLO 2.6][APLO 2.28][APLO 2.42][APLO 4.9][APLO 4.1]

Not all prokaryotes are pathogenic. On the contrary, pathogens represent only a very small percentage of the diversity of the microbial world. In fact, our life would not be possible without prokaryotes. Just think about the role of prokaryotes in biogeochemical cycles.

Cooperation between Bacteria and Eukaryotes: Nitrogen Fixation

Nitrogen is a very important element to living things, because it is part of nucleotides and amino acids that are the building blocks of nucleic acids and proteins, respectively. Nitrogen is usually the most limiting element in terrestrial ecosystems, with atmospheric nitrogen, N2, providing the largest pool of available nitrogen. However, eukaryotes cannot use atmospheric, gaseous nitrogen to synthesize macromolecules. Fortunately, nitrogen can be “fixed,” meaning it is converted into ammonia (NH3) either biologically or abiotically. Abiotic nitrogen fixation occurs as a result of lightning or by industrial processes.

Biological nitrogen fixation (BNF) is exclusively carried out by prokaryotes: soil bacteria, cyanobacteria, and Frankia spp. (filamentous bacteria interacting with actinorhizal plants such as alder, bayberry, and sweet fern). After photosynthesis, BNF is the second most important biological process on Earth. The equation representing the process is as follows

where Pi stands for inorganic phosphate. The total fixed nitrogen through BNF is about 100 to 180 million metric tons per year. Biological processes contribute 65 percent of the nitrogen used in agriculture.

Cyanobacteria are the most important nitrogen fixers in aquatic environments. In soil, members of the genus Clostridium are examples of free-living, nitrogen-fixing bacteria. Other bacteria live symbiotically with legume plants, providing the most important source of BNF. Symbionts may fix more nitrogen in soils than free-living organisms by a factor of 10. Soil bacteria, collectively called rhizobia, are able to symbiotically interact with legumes to form nodules, specialized structures where nitrogen fixation occurs (Figure 22.27). Nitrogenase, the enzyme that fixes nitrogen, is inactivated by oxygen, so the nodule provides an oxygen-free area for nitrogen fixation to take place. This process provides a natural and inexpensive plant fertilizer, as it reduces atmospheric nitrogen to ammonia, which is easily usable by plants. The use of legumes is an excellent alternative to chemical fertilization and is of special interest to sustainable agriculture, which seeks to minimize the use of chemicals and conserve natural resources. Through symbiotic nitrogen fixation, the plant benefits from using an endless source of nitrogen: the atmosphere. Bacteria benefit from using photosynthates (carbohydrates produced during photosynthesis) from the plant and having a protected niche. Additionally, the soil benefits from being naturally fertilized. Therefore, the use of rhizobia as biofertilizers is a sustainable practice.

Why are legumes so important? Some, like soybeans, are key sources of agricultural protein. Some of the most important grain legumes are soybean, peanuts, peas, chickpeas, and beans. Other legumes, such as alfalfa, are used to feed cattle.

Early Biotechnology: Cheese, Bread, and Yogurt

According to the United Nations Convention on Biological Diversity, biotechnology is “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use." 5 The concept of “specific use” involves some sort of commercial application. Genetic engineering, artificial selection, antibiotic production, and cell culture are current topics of study in biotechnology. However, humans have used prokaryotes before the term biotechnology was even coined. In addition, some of the goods and services are as simple as cheese, bread, and yogurt, which employ both bacteria and other microbes, such as yeast, a fungus.

Cheese production began around 4,000–7,000 years ago when humans began to breed animals and process their milk. Fermentation in this case preserves nutrients: Milk will spoil relatively quickly, but when processed as cheese, it is more stable Evidence suggests that cultured milk products, like yogurt, have existed for at least 4,000 years.

Using Prokaryotes to Clean up Our Planet: Bioremediation

Microbial bioremediation is the use of prokaryotes (or microbial metabolism) to remove pollutants. Bioremediation has been used to remove agricultural chemicals (pesticides, fertilizers) that leach from soil into groundwater and the subsurface. Certain toxic metals and oxides, such as selenium and arsenic compounds, can also be removed from water by bioremediation. The reduction of SeO4 -2 to SeO3 -2 and to Se 0 (metallic selenium) is a method used to remove selenium ions from water. Mercury is an example of a toxic metal that can be removed from an environment by bioremediation. As an active ingredient of some pesticides, mercury is used in industry and is also a by-product of certain processes, such as battery production. Methyl mercury is usually present in very low concentrations in natural environments, but it is highly toxic because it accumulates in living tissues. Several species of bacteria can carry out the biotransformation of toxic mercury into nontoxic forms. These bacteria, such as Pseudomonas aeruginosa, can convert Hg +2 into Hg 0 , which is nontoxic to humans.

One of the most useful and interesting examples of the use of prokaryotes for bioremediation purposes is the cleanup of oil spills. The importance of prokaryotes to petroleum bioremediation has been demonstrated in several oil spills in recent years, such as the Exxon Valdez spill in Alaska (1989) (Figure 22.28), the Prestige oil spill in Spain (2002), the spill into the Mediterranean from a Lebanon power plant (2006), and more recently, the Deepwater Horizon oil spill in the Gulf of Mexico (2010). To clean up these spills, bioremediation is promoted by the addition of inorganic nutrients that help bacteria to grow. Hydrocarbon-degrading bacteria feed on hydrocarbons in the oil droplet, breaking down the hydrocarbons. Some species, such as Alcanivorax borkumensis, produce surfactants that solubilize the oil, whereas other bacteria degrade the oil into carbon dioxide. In the case of oil spills in the ocean, ongoing, natural bioremediation tends to occur, inasmuch as there are oil-consuming bacteria in the ocean prior to the spill. In addition to naturally occurring oil-degrading bacteria, humans select and engineer bacteria that possess the same capability with increased efficacy and spectrum of hydrocarbon compounds that can be processed. Under ideal conditions, it has been reported that up to 80 percent of the nonvolatile components in oil can be degraded within one year of the spill. Other oil fractions containing aromatic and highly branched hydrocarbon chains are more difficult to remove and remain in the environment for longer periods of time.

Everyday Connection for AP® Courses

A particularly fascinating example of our normal flora relates to our digestive systems. People who take high doses of antibiotics tend to lose many of their normal gut bacteria, allowing a naturally antibiotic-resistant species called Clostridium difficile to overgrow and cause severe gastric problems, especially chronic diarrhea. Obviously, trying to treat this problem with antibiotics only makes it worse. However, it has been successfully treated by giving the patients fecal transplants from healthy donors to reestablish the normal intestinal microbial community. Scientists are also discovering that the absence of certain key microbes from our intestinal tract may set us up for a variety of problems including obesity, insulin resistance, and autoimmune disorders. Pictured here is a scanning electron micrograph of Clostridium difficile, a Gram-positive, rod-shaped bacterium that causes severe diarrhea. Infection commonly occurs after the normal gut fauna is eradicated by antibiotics.


22.5 Beneficial Prokaryotes

By the end of this section, you will be able to do the following:

  • Explain the need for nitrogen fixation and how it is accomplished
  • Describe the beneficial effects of bacteria that colonize our skin and digestive tracts
  • Identify prokaryotes used during the processing of food
  • Describe the use of prokaryotes in bioremediation

Fortunately, only a few species of prokaryotes are pathogenic! Prokaryotes also interact with humans and other organisms in a number of ways that are beneficial. For example, prokaryotes are major participants in the carbon and nitrogen cycles. They produce or process nutrients in the digestive tracts of humans and other animals. Prokaryotes are used in the production of some human foods, and also have been recruited for the degradation of hazardous materials. In fact, our life would not be possible without prokaryotes!

Cooperation between Bacteria and Eukaryotes: Nitrogen Fixation

Nitrogen is a very important element to living things, because it is part of nucleotides and amino acids that are the building blocks of nucleic acids and proteins, respectively. Nitrogen is usually the most limiting element in terrestrial ecosystems, with atmospheric nitrogen, N2, providing the largest pool of available nitrogen. However, eukaryotes cannot use atmospheric, gaseous nitrogen to synthesize macromolecules. Fortunately, nitrogen can be “fixed,” meaning it is converted into a more accessible form—ammonia (NH3)—either biologically or abiotically.

Abiotic nitrogen fixation occurs as a result of physical processes such as lightning or by industrial processes. Biological nitrogen fixation (BNF) is exclusively carried out by prokaryotes: soil bacteria, cyanobacteria, and Frankia spp. (filamentous bacteria interacting with actinorhizal plants such as alder, bayberry, and sweet fern). After photosynthesis, BNF is the most important biological process on Earth. The overall nitrogen fixation equation below represents a series of redox reactions (Pi stands for inorganic phosphate).

The total fixed nitrogen through BNF is about 100 to 180 million metric tons per year, which contributes about 65 percent of the nitrogen used in agriculture.

Cyanobacteria are the most important nitrogen fixers in aquatic environments. In soil, members of the genera Clostridium and Azotobacter are examples of free-living, nitrogen-fixing bacteria. Other bacteria live symbiotically with legume plants, providing the most important source of fixed nitrogen. Symbionts may fix more nitrogen in soils than free-living organisms by a factor of 10. Soil bacteria, collectively called rhizobia, are able to symbiotically interact with legumes to form nodules , specialized structures where nitrogen fixation occurs (Figure 22.27). Nitrogenase, the enzyme that fixes nitrogen, is inactivated by oxygen, so the nodule provides an oxygen-free area for nitrogen fixation to take place. The oxygen is sequestered by a form of plant hemoglobin called leghemoglobin, which protects the nitrogenase, but releases enough oxygen to support respiratory activity.

Symbiotic nitrogen fixation provides a natural and inexpensive plant fertilizer: It reduces atmospheric nitrogen to ammonia, which is easily usable by plants. The use of legumes is an excellent alternative to chemical fertilization and is of special interest to sustainable agriculture, which seeks to minimize the use of chemicals and conserve natural resources. Through symbiotic nitrogen fixation, the plant benefits from using an endless source of nitrogen: the atmosphere. The bacteria benefit from using photosynthates (carbohydrates produced during photosynthesis) from the plant and having a protected niche. In addition, the soil benefits from being naturally fertilized. Therefore, the use of rhizobia as biofertilizers is a sustainable practice.

Why are legumes so important? Some, like soybeans, are key sources of agricultural protein. Some of the most important legumes consumed by humans are soybeans, peanuts, peas, chickpeas, and beans. Other legumes, such as alfalfa, are used to feed cattle.

Everyday Connection

Microbes on the Human Body

The commensal bacteria that inhabit our skin and gastrointestinal tract do a host of good things for us. They protect us from pathogens, help us digest our food, and produce some of our vitamins and other nutrients. These activities have been known for a long time. More recently, scientists have gathered evidence that these bacteria may also help regulate our moods, influence our activity levels, and even help control weight by affecting our food choices and absorption patterns. The Human Microbiome Project has begun the process of cataloging our normal bacteria (and archaea) so we can better understand these functions.

A particularly fascinating example of our normal flora relates to our digestive systems. People who take high doses of antibiotics tend to lose many of their normal gut bacteria, allowing a naturally antibiotic-resistant species called Clostridium difficile to overgrow and cause severe gastric problems, especially chronic diarrhea (Figure 22.28). Obviously, trying to treat this problem with antibiotics only makes it worse. However, it has been successfully treated by giving the patients fecal transplants from healthy donors to reestablish the normal intestinal microbial community. Clinical trials are underway to ensure the safety and effectiveness of this technique.

Scientists are also discovering that the absence of certain key microbes from our intestinal tract may set us up for a variety of problems. This seems to be particularly true regarding the appropriate functioning of the immune system. There are intriguing findings that suggest that the absence of these microbes is an important contributor to the development of allergies and some autoimmune disorders. Research is currently underway to test whether adding certain microbes to our internal ecosystem may help in the treatment of these problems, as well as in treating some forms of autism.

Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt

According to the United Nations Convention on Biological Diversity, biotechnology is “any technological application that uses biological systems, living organisms, or derivatives thereof, to make or modify products or processes for specific use." 5 The concept of “specific use” involves some sort of commercial application. Genetic engineering, artificial selection, antibiotic production, and cell culture are current topics of study in biotechnology and will be described in later chapters. However, humans were using prokaryotes before the term biotechnology was even coined. Some of the products of this early biotechnology are as familiar as cheese, bread, wine, beer, and yogurt, which employ both bacteria and other microbes, such as yeast, a fungus (Figure 22.29).

Cheese production began around 4,000 to 7,000 years ago when humans began to breed animals and process their milk. Fermentation in this case preserves nutrients: Milk will spoil relatively quickly, but when processed as cheese, it is more stable. As for beer, the oldest records of brewing are about 6,000 years old and were an integral part of the Sumerian culture. Evidence indicates that the Sumerians discovered fermentation by chance. Wine has been produced for about 4,500 years, and evidence suggests that cultured milk products, like yogurt, have existed for at least 4,000 years.

Using Prokaryotes to Clean up Our Planet: Bioremediation

Microbial bioremediation is the use of prokaryotes (or microbial metabolism) to remove pollutants. Bioremediation has been used to remove agricultural chemicals (e.g., pesticides, fertilizers) that leach from soil into groundwater and the subsurface. Certain toxic metals and oxides, such as selenium and arsenic compounds, can also be removed from water by bioremediation. The reduction of SeO4 -2 to SeO3 -2 and to Se 0 (metallic selenium) is a method used to remove selenium ions from water. Mercury (Hg) is an example of a toxic metal that can be removed from an environment by bioremediation. As an active ingredient of some pesticides, mercury is used in industry and is also a by-product of certain processes, such as battery production. Methyl mercury is usually present in very low concentrations in natural environments, but it is highly toxic because it accumulates in living tissues. Several species of bacteria can carry out the biotransformation of toxic mercury into nontoxic forms. These bacteria, such as Pseudomonas aeruginosa, can convert Hg +2 into Hg 0 , which is nontoxic to humans.

One of the most useful and interesting examples of the use of prokaryotes for bioremediation purposes is the cleanup of oil spills. The significance of prokaryotes to petroleum bioremediation has been demonstrated in several oil spills in recent years, such as the Exxon Valdez spill in Alaska (1989) (Figure 22.30), the Prestige oil spill in Spain (2002), the spill into the Mediterranean from a Lebanon power plant (2006), and more recently, the BP oil spill in the Gulf of Mexico (2010). In the case of oil spills in the ocean, ongoing natural bioremediation tends to occur, since there are oil-consuming bacteria in the ocean prior to the spill. In addition to these naturally occurring oil-degrading bacteria, humans select and engineer bacteria that possess the same capability with increased efficacy and spectrum of hydrocarbon compounds that can be processed. Bioremediation is enhanced by the addition of inorganic nutrients that help bacteria to grow.

Some hydrocarbon-degrading bacteria feed on hydrocarbons in the oil droplet, breaking down the hydrocarbons into smaller subunits. Some species, such as Alcanivorax borkumensis, produce surfactants that solubilize the oil (making it soluble in water), whereas other bacteria degrade the oil into carbon dioxide. Under ideal conditions, it has been reported that up to 80 percent of the nonvolatile components in oil can be degraded within one year of the spill. Other oil fractions containing aromatic and highly branched hydrocarbon chains are more difficult to remove and remain in the environment for longer periods of time.


Traditional medicines

Some traditional medicines also used organisms or parts of organisms. For example, the ancient Egyptians used honey for respiratory infections and as an ointment for wounds. Honey is a natural antibiotic , killing the germs in wounds.

By about 600BC, the Chinese were using mouldy soybean curds to treat boils. Similarly, Ukrainian peasants were using mouldy cheese to treat infected wounds. The moulds released natural antibiotics that killed bacteria and prevented the spread of infection . Despite these natural treatments, it wasn’t until 1928 that Alexander Fleming first extracted penicillin – the first antibiotic – from mould .


Free Response

Your friend believes that prokaryotes are always detrimental and pathogenic. How would you explain to them that they are wrong?

Remind them of the important roles prokaryotes play in decomposition and freeing up nutrients in biogeochemical cycles remind them of the many prokaryotes that are not human pathogens and that fill very specialized niches. Furthermore, our normal bacterial symbionts are crucial for our digestion and in protecting us from pathogens.


Using Prokaryotes to Clean up Our Planet: Bioremediation

Microbial bioremediation is the use of prokaryotes (or microbial metabolism) to remove pollutants. Bioremediation has been used to remove agricultural chemicals (pesticides, fertilizers) that leach from soil into groundwater and the subsurface. Certain toxic metals and oxides, such as selenium and arsenic compounds, can also be removed from water by bioremediation. The reduction of SeO4 -2 to SeO3 -2 and to Se 0 (metallic selenium) is a method used to remove selenium ions from water. Mercury is an example of a toxic metal that can be removed from an environment by bioremediation. As an active ingredient of some pesticides, mercury is used in industry and is also a by-product of certain processes, such as battery production. Methyl mercury is usually present in very low concentrations in natural environments, but it is highly toxic because it accumulates in living tissues. Several species of bacteria can carry out the biotransformation of toxic mercury into nontoxic forms. These bacteria, such as Pseudomonas aeruginosa, can convert Hg +2 into Hg 0 , which is nontoxic to humans.

One of the most useful and interesting examples of the use of prokaryotes for bioremediation purposes is the cleanup of oil spills. The importance of prokaryotes to petroleum bioremediation has been demonstrated in several oil spills in recent years, such as the Exxon Valdez spill in Alaska (1989) ([Figure 3]), the Prestige oil spill in Spain (2002), the spill into the Mediterranean from a Lebanon power plant (2006), and more recently, the BP oil spill in the Gulf of Mexico (2010). To clean up these spills, bioremediation is promoted by the addition of inorganic nutrients that help bacteria to grow. Hydrocarbon-degrading bacteria feed on hydrocarbons in the oil droplet, breaking down the hydrocarbons. Some species, such as Alcanivorax borkumensis, produce surfactants that solubilize the oil, whereas other bacteria degrade the oil into carbon dioxide. In the case of oil spills in the ocean, ongoing, natural bioremediation tends to occur, inasmuch as there are oil-consuming bacteria in the ocean prior to the spill. In addition to naturally occurring oil-degrading bacteria, humans select and engineer bacteria that possess the same capability with increased efficacy and spectrum of hydrocarbon compounds that can be processed. Under ideal conditions, it has been reported that up to 80 percent of the nonvolatile components in oil can be degraded within one year of the spill. Other oil fractions containing aromatic and highly branched hydrocarbon chains are more difficult to remove and remain in the environment for longer periods of time.

Figure 3: (a) Cleaning up oil after the Valdez spill in Alaska, workers hosed oil from beaches and then used a floating boom to corral the oil, which was finally skimmed from the water surface. Some species of bacteria are able to solubilize and degrade the oil. (b) One of the most catastrophic consequences of oil spills is the damage to fauna. (credit a: modification of work by NOAA credit b: modification of work by GOLUBENKOV, NGO: Saving Taman)

Microbes on the Human Body The commensal bacteria that inhabit our skin and gastrointestinal tract do a host of good things for us. They protect us from pathogens, help us digest our food, and produce some of our vitamins and other nutrients. These activities have been known for a long time. More recently, scientists have gathered evidence that these bacteria may also help regulate our moods, influence our activity levels, and even help control weight by affecting our food choices and absorption patterns. The Human Microbiome Project has begun the process of cataloging our normal bacteria (and archaea) so we can better understand these functions.

A particularly fascinating example of our normal flora relates to our digestive systems. People who take high doses of antibiotics tend to lose many of their normal gut bacteria, allowing a naturally antibiotic-resistant species called Clostridium difficile to overgrow and cause severe gastric problems, especially chronic diarrhea ([Figure 4]). Obviously, trying to treat this problem with antibiotics only makes it worse. However, it has been successfully treated by giving the patients fecal transplants from healthy donors to reestablish the normal intestinal microbial community. Clinical trials are underway to ensure the safety and effectiveness of this technique.

Figure 4: This scanning electron micrograph shows Clostridium difficile, a Gram-positive, rod-shaped bacterium that causes severe diarrhea. Infection commonly occurs after the normal gut fauna is eradicated by antibiotics. (credit: modification of work by CDC, HHS scale-bar data from Matt Russell)

Scientists are also discovering that the absence of certain key microbes from our intestinal tract may set us up for a variety of problems. This seems to be particularly true regarding the appropriate functioning of the immune system. There are intriguing findings that suggest that the absence of these microbes is an important contributor to the development of allergies and some autoimmune disorders. Research is currently underway to test whether adding certain microbes to our internal ecosystem may help in the treatment of these problems as well as in treating some forms of autism.


Examples of Beer's law in the following topics:

Experimental Determination of Reaction Rates

  • If we know the order of the reaction, we can plot the data and apply our integrated rate laws.
  • The absorbance is given by Beer'slaw:
  • By Beer'slaw, the absorbance of the solution is directly proportional to the concentration of the C60O3 in solution, so observing the absorbance as a function of time is essentially the same as observing the concentration as a function of time.
  • In this case, the rate law is given by:
  • As discussed in a previous concept, plots derived from the integrated rate laws for various reaction orders can be used to determine the rate constant k.

US commercial centers, trade intermediaries, and alliances

  • They have commercial law information and trade promotion facilities, including the facilitation of contacts between buyers, sellers, bankers, distributors, agents, and government officials.
  • Heineken, the premium Dutch beer, is consumed by more people in more countries than any other beer.
  • Melcher, "Heineken's Battle to Stay Top Bottle," Business Week, August 1, 1998, pp. 60-62. ) It is also the number-one imported beer in America.
  • Miller and Budweiser, the two largest American beer producers, have entered into global competition with Heineken, partly because the American beer market has been flat.
  • Heineken has also begun developing an alliance with Asia Pacific Breweries, the maker of Tiger Beer.

Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt

Clearing the Market at Equilibrium Price and Quantity

  • A textbook example of a monopoly was the Da Beers family, who owned the vast majority of diamond mines worldwide.
  • Through effectively controlling the diamond market supply (via owning the mines), and warehousing the diamonds in a way to substantially alter the available supply, it became reasonably easy for Da Beers to charge prices in excess of what a reasonable equilibrium would be.
  • This definition requires a variety of assumptions which simplify the complexities of real markets to coincide with a more theoretical framework, most centrally the assumptions of perfect competition and Say's Law:
  • Say's Law hinges on the concept that capital loses value over time, or that money is essentially perishable.
  • The simplest way to view this law is interest rates.

Resource Control

  • A classic example of a monopoly based on resource control is De Beers .
  • De Beers also purchased and stockpiled diamonds produced by other manufacturers in order to control prices through supply.
  • The De Beers model changed at the turn of the 21st century, when diamond producers from Russia, Canada, and Australia started to distribute diamonds outside of the De Beers channel.
  • De Beers' market share fell from as high as 90 percent in the 1980s to less than 40 percent in 2012.
  • For most of the 20th century, De Beers had monopoly power over the world market for diamonds.

Prohibition

  • Effective enforcement of the ban proved to be difficult, however, and led to widespread flouting of the law, as well as a massive escalation of organized crime.
  • A total of 1,520 Prohibition agents from three separate federal agencies – the Coast Guard Office of Law Enforcement, the Treasury Department/Internal Revenue Service Bureau of Prohibition, and the Department of Justice Bureau of Prohibition – were tasked with enforcing the new law.
  • The beer that could be legally consumed was essentially a very weak mixture.
  • Roosevelt signed an amendment to the Volstead Act known as the Cullen-Harrison Act, allowing the manufacture and sale of light wine and "3.2 beer", referring to 3.2% alcohol content.
  • Upon signing the amendment, Roosevelt made his famous remark: "I think this would be a good time for a beer."

The Prohibition Movement

  • Private ownership and consumption of alcohol were not made illegal under federal law however, in many areas, local laws were stricter, with some states banning possession outright.
  • Millions could be made by taxing beer.
  • On March 22, 1933, President Franklin Roosevelt signed an amendment to the Volstead Act, known as the Cullen–Harrison Act, allowing the manufacture and sale of 3.2% beer and light wines.
  • Upon signing the Cullen–Harrison Act, Roosevelt made his famous remark: "I think this would be a good time for a beer."
  • Some researchers contend that its political failure is attributable more to a changing historical context than to characteristics of the law itself.

Other Barriers to Entry

  • For example, De Beers controls the vast majority of the world's diamond reserves, allowing only a certain number of diamonds to be mined each year and keeping the price of diamonds high .
  • There are cases in which a government agency is the sole provider of a particular good or service and competition is prohibited by law.
  • For example, in many countries, the postal system is run by the government with competition forbidden by law in some or all services.
  • De Beers controls the majority of the world's diamond reserves, preventing other players from entering the industry and setting a high price for diamonds.

Wine, Beer, and Alcohol

  • Beer is the most consumed alcoholic beverage in the world.
  • The process of making beer is called brewing.
  • Beer brewing in modern days is performed by added pure cultures of the desired yeast species to the wort.
  • Additional yeasts species that are used in making beer are Dekkera/Brettanomyces.
  • Explain why microorganisms are used for beer, wine, and sake production.

Early Biotechnology: Cheese, Bread, Wine, Beer, and Yogurt

  • Some of the earliest biotechnology used prokaryotes for the production of food products such as cheese, bread, wine, beer, and yogurt.
  • Some of the products are as simple as cheese, bread, wine, beer, and yogurt,which employ both bacteria and other microbes, such as yeast .
  • Records of brewing beer date back about 6,000 years to the Sumerians.
  • Some of the products derived from the use of prokaryotes in early biotechnology include (a) cheese, (b) wine, (c) beer and bread, and (d) yogurt.
  • Discuss the origins of food biotechnology as indicated by the production of cheese, bread, wine, beer, and yogurt
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Ripening the cheese

Cheese is left to ripen, or age, in a temperature and humidity-controlled environment for varying lengths of time depending on the cheese type. As cheese ripens, bacteria break down the proteins, altering the flavour and texture of the final cheese. The proteins first break into medium-sized pieces ( peptides ) and then into smaller pieces ( amino acids ). In turn, these can be broken down into various, highly flavoured molecules called amines. At each stage, more complex flavours are produced.

During ripening, some cheeses are inoculated with a fungus such as Penicillium. Inoculation can be either on the surface (for example, with Camembert and Brie) or internally (for example, with blue vein cheeses). During ripening, the fungi produce digestive enzymes, which break down large protein molecules in the cheese. This makes the cheese softer, runny and even blue.

Cheese comes in many varieties of different styles, textures and flavours, find our more on creating some of these different cheese characteristics.