Fermentation converts glucose into pyruvic acid and ethanol. The ethanol is the alcohol part in the process. Fermentation as a type of reaction occurring inside cells is anaerobic in nature, yeast are used during the fermentation process as well as other bacteria like halophilic microbes of class Streptococcus. Biotechnology have evolved through centuries, with yeast being the first to be used in the process of making beer. Biotechnology scientist like Pasteur, Koch, and Buchner are accredited for the evolution of theories of fermentation on various products (Klaus & John, 2013). The research contributions by theses scientist formed the basis for making citric acids, penicillin, and explosives that were used in the Second World War. There are two major types of fermentation that is alcoholic and lactic; in alcohol fermentation ethanol and carbon (IV) oxide is produced. In lactic fermentation, sugar molecules are converted into lactic acid without the release of carbon (IV) oxide. Beer, bread, and wines are some of the products from the process of fermentation. The paper will discuss alcohol fermentation as the basis of its emphasis since fermentation is applied mostly in the production of the alcoholic product.
With humanitarian and environmental activist accompanied by declining availability of sources of energy especially oil, the idea of renewable sources of energy have been given attention globally. Alcohol can be used in place of petrol to produce the energy required to drive locomotives and industrial machinery. Starch is readily available for production of alcohol needed for energy production. The study finds the challenge of managing components like fibers in the starch that blocks the bioreactor making the production of energy unsustainable hence unreliable. Alcohol fermentation results in the manufacture of beer, wines, and energy.
The fermentation process is dated back to 6,000 years ago, Sumerians are the first human beings to experience civilization and are also the first one to have documented the process of fermentation. In Mesopotamia, it was used to generate income since it was used to make beers and wines that were sold or trade for other goods. The fermentation process was so practical, and its importance in making bread and alcoholic drinks gained technical and scholarly interest (Klaus & John, Intro para, 2013). Various scholars with different rationales concerning the mechanism of fermentation resulted in different theories and ideas about materialism and vitalism that contributed to the current biochemical reactions understanding.
Fermentation in The early period- till 1850
By 1680, there was no exact explanation concerning fermentation although the process had been used from centuries ago. For instance, Leeuwenhoek with the aid of his microscope observed various forms of liquids and noticed microscopic organisms but he did not associate them with the process of fermentation. However, some scientists like Gay-Lusacc and Lavoisier had conducted studies on the process of fermentation and linked it with the process of making alcohol but could not explain how fermentation could result in the production of alcohol. In mid of 17th century by efforts of a scientist like Schwann, a biological knowledge behind fermentation had started to accumulate. The fermentation process was linked to the reactions of yeast cells, which were assumed to be alive. Schwann and Cagniard – Latour experimented and concluded that the body of yeast cells were globular in shape that could reproduce asexually. The two scientist conducted their research separately, and the likeness of their idea about fermentation drew credibility to the explanation they gave concerning alcohol fermentation. Their research findings were used years later by scientist like Louis Pasteur as the basis of their further studies and discoveries concerning fermentation. Some scientists like Kutzing proposed that living organisms can regenerate themselves by spontaneous reactions between organizing a living force and chemical components. Some nations like the United Kingdom were already brewing in large fermenters in industries on large scales, while, in German, it was done manually by 1837. Fermentation of beer was first, followed by wine and soya later in years (Klaus & John, 2013).
About Louis Pasteur
Pasteur is reckoned as one of the great scientists due to his massive scientific discoveries ranging from crystals of life, the process of fermentation and the science of vaccination in the field of medicine. Louis gave a credible explanation concerning fermentation and the putrefaction process linked to microorganism’s actions (Berche, 2012). Fermentation was explained on the basis of spontaneous generation of living organisms, but Pasteur replaced the account as caused by microbes from the yeast catalyzing the fermentation process. With evolved explanation, the naturalist explained that fermentation of sugar to produce alcohol was as a result of catalytic reaction by enzymes in the yeast. Louise in his study life was presented with a case by a beer company on alcohol contamination by other products during fermentation. He conducted studies and noticed globule shaped bodies that were not yeast and later discovered it was bacteria. The bacteria were linked to the contamination of the beer during fermentation. He conducted the test using ferment juice and noticed that the juice had moving microorganisms, the moving component was discovered to be amyl alcohol. Pasteur concluded that the globules were the one responsible for causing fermentation by the process of organizing themselves, developing and replication (Berche, 2012). With his advanced knowledge he conducted studies of fermentation of wine, vinegar, and sour milk; this contributed the knowledge behind all fermentation process is caused by a ferment. The ferment is a living organism that could be bacteria or yeast. Previously before the study of Louis on the alcohol contamination, it was noticed that the contaminants were not impurities but were factors that enhanced the fermentation process (Berche, 2012). His studies on lactic acid fermentation formed the basis of the germ theory that is used to explain the causative of diseases today.
Pasteur suggested that when sugar is nurtured with yeast, it breaks down, and this process is fermentation. In this medium, he suggested that yeast cells develop, and multiply and the process occur when yeast cells feed on the sugar. The feeding process leads to fermentation and alcohol alongside other products are produced. With the feeding property of the yeast cells, Pasteur concluded that fermentation is a result of living cells action. Pasteur found that the feeding aspect is the vital phenomenon that forms the theory of vitalism (Klaus & John 2013). With his research findings, he refuted the Liebig’s ideas about fermentation and affirmed that yeast grows and ferments sugar, and the medium have to be acidic in the absence of protein elements.
Process of Fermentation
In the process of fermentation the enzymatic action of the yeast, converts sugars like maltose into alcohol, two molecules of the three-carbon organic acid, and energy. During the process before ethyl (alcohol) is obtained, there are various intermediate products formed. For enzymatic reaction fascinated to occur, an acidic medium is required for fermentation products to be fermented introduced (Fermentation, 2015). Acid content may not be sufficient, and material with acidic nature are added before adding the prepared yeast. Sugars are added, and the sugar content is adjusted to ensure the total percentage of alcohol formed is between 7 and 9 percent (Alan Thomas & Frank , 2015)
Types of Fermentation
The following are the types of fermentation as discussed.
Alcohol fermentation can be achieved by using various forms of starch of products that has sugar content. In a given research study conducted by Zhejiang University, a mash of dried sweet potatoes was used together with yeast cells to demonstrate the process of fermentation. They used immobilized yeast cells since they facilitate a faster rate of fermentation, and they have a high density. The density was enhanced by placing the yeast cells in a medium that promotes their multiplication. The medium for multiplication contained a mash of sweet potatoes and calcium alginate- entrapped Saccharomyces cerevisiae k (Bingjun, Fuming, Yugao & Pu, 1996). The population of yeast cells of the immobilized yeast cell beads was checked after and before multiplication of yeast cells. New cells were noticed on the surface of the beads that was explained by the fact that on the surface of the beads, there are high chances of getting nutrients and getting rid of metabolites. In a different control experiment, fermentation was conducted using gel beads that are not sliced. The process of fermentation was faster when thin gel slices (immobilized yeast cells). The slices gel created a large surface area for the reaction between the enzymes (catalyst) to occur, which facilitated fermentation process.
Glycolysis is the process by which sugar is broken into lactate. In glycolysis a six carbon sugar is broken down into an organic acid with three carbon structure made up of two molecules. The acid is called pyruvic, and it is unionized, during the reaction there is the production of energy during the process. The organic acid in aerobic or anaerobic reaction and be converted to alcohol, lactic acid, and other products. The process for conversion of glucose to pyruvate acid is named after two German scientists Embden-Meyerhof. The two scientists were the one who hypothesized and performed experiments to explain the sequence of steps that are involved in the glycolysis pathway (Fermentation, 2015). In cells, a similar process as fermentation occur that leads to the breakdown of glucose and production of energy. In situations where oxygen is inadequate especially in muscles during intense exercise, less energy and pyruvic acid is produced and undergoes oxidation to avoid muscle cramping. The sequence is catalyzed by enzymes found in the cytoplasm that takes the place of yeast in the fermentation process.
In a research study to confirm that fermentation utilizes sugars, the University of Kansas in the department of chemical engineering tested the presence of glycerol in a media. Glycerol is used to provide the carbon required during fermentation. High-performance liquid chromatography (HPLC) is applied in determining the presence of glycerol in a fermentation media. HPLC method is expensive since various samples from the fermentation process, and different kits to detect glycerol process are required (Jennifer, Hagen, Denise & Peter, 2015). To accomplish the study in a cost-effective way, they used a combination of malaparade reaction and the Hantzsch reactions. Since the reactions are also used to detect the process of glycerol and 1, 2-diol. In the reaction, glycerol is converted into formaldehyde, by the use of periodate. Hantzsch reaction is initiated to help detect the presence of Formaldehyde.
The process is initiated once the required conditions have been checked and confirmed. The conditions include the creation of acidic medium and ensuring the levels of nutrients needed for fermentation are proportionate to some enzymes. During the process, biofuel is produced that is ethyl alcohol. In industries, the process is intentional, and catalyst like fungi and bacteria are used to make food products. The rate of production of desired fermented products depends on the amount of microorganism, enzymes, temperature and level of acidity. In industrial ferments enzymes are produced rennet and lipase (Fermentation, 2015). Four steps are involved which include the production of biomass that is a viable material from a cell. The second step is the production of metabolites that are components outside the cells that contain acids to provide necessary Ph. The third stage is the production of intracellular components which includes the enzymes that catalyze the reaction. The last one is the conversion of substrates into required products.
Role of yeast enzymes
In the production of alcoholic drinks like wine and beer processed and natural enzymes are used to catalyze fermentation reaction. Currently barley in beer brewing is used as enzymes to ferment sugars. For instance, in the production of wine grapes are used. Grapes have sugars that are fermented by yeast in winemaking. Bechamp over the year’s studied the contribution of micro enzymes in fermentation (Manchester, 2007). Germinated barley or other cereal like millet, once they are germinated for about six days, the germinated product is used as the enzyme for fermentation. Some enzymes like b- amylase is already in the barley with a water content of not more than 5%. The germination process is vital for it’s the one responsible for multiplication of enzymes for fermentation. The germination aims to increase the concentration of a-amylase that is required together with proteases for the fermentation process. Enzymes from malt can only work if subjected to right temperatures and Ph.
Role of oxygen
Saccharomyces cerevisiae and Saccharomyces avaram are species of yeast that is used by beer brewer and other alcoholic drinks. Yeast cell requires oxygen for respiration and growth before they can be ready to ferment sugars (Contreras, Hidalgo, Schmidt, Henschke, Curtin & Verela, 2015). Pasteur state from his studies that yeast contains living microorganism responsible for fermentation and the use of oxygen for respiration confirm the rationale.
Role of pH
In fermentation, lower pH is suitable for the process. Enzymes handle the reactions involved in the fermentation process. Enzymes are protein in nature, and pH affects their shape (Contreras, et al. 2015). The form of enzymes and a substrate that are the sugars required for fermentation have to be complementary in nature, and this can only be enhanced with a low PH.
In conclusion, fermentation is a process that have been used for centuries to create social and commercial products. Fermentation is not only applied in the manufacturing of drinks but also in the production of foods like bread and sour milk. The process of fermentation was widespread in the ancient world, but there was no explanation of the involved mechanism. Scientist like Louis Pasteur dedicated their studies on the mechanism to make sense. Once the mechanism were understood in current day enzymes are manufactured in the laboratories to facilitate fermentation rather than relying primarily of natural enzymes like barley and yeast.
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