Introduction to Microbiology
Question 1.
Rewrite the following statements using correct of the options and explain the completed statements.
(gluconic acid, coagulation, amino acid, 4% acetic acid, clostridium, lactobacilli)
a. Process of ……. of milk proteins occurs due to lactic acid.
Answer: Coagulation
Explanation: The lactobacilli are the bacteria carrying out fermentation of the milk. In this process, the lactose sugar in the milk is converted into lactic acid. This lactic acid causes coagulation of the proteins present in the milk.
b. Harmful bacteria like ………. in the intestine are destroyed due to probiotics.
Answer: Clostridium
Explanation: In probiotics, there are lactobacilli which are useful. They control other bacteria present in the alimentary canal and also their metabolism. These bacteria thus stop the action of Clostridium which is a harmful bacteria.
c. Chemically, vinegar is …………
Answer: 4% Acetic acid
Explanation: Chemically vinegar is 4% acetic acid. It is a good preservative of the food and thus while using it as additive to the food, it is called vinegar.
d. Salts which can be used as supplement of calcium and iron are obtained from ……………. acid.
Answer: Gluconic
Explanation: The microbe Aspergillus niger is used on the source material of glucose and corn steep liquor to produce amino acid called Gluconic acid. Gluconic acid is used for the production of minerals used as supplement for calcium and iron.
Question 2.
Match the pairs.
| ‘A’ group | ‘B’ group |
| (1) Xylitol | (a) Pigment |
| (2) Citric acid | (b) To impart sweetness |
| (3) Lycopene | (c) Microbial restrictor |
| (4) Nycin | (d) Protein binding emulsifier |
| (e) To impart acidity |
Answer:
(1) Xylitol – To impart sweetness
(2) Citric acid – To impart acidity
(3) Lycopene – Pigment
(4) Nycin – Microbial restrictor.
Question 3.
Answer the following:
a. Which fuels can be obtained by microbial processes? Why is it necessary to increase the use of such fuels?
Answer:
There are different kinds of fuel that can be produced with the help of microbes. Some of the examples of such fuels are:
- Ethanol: It is a byproduct that is produced during fermentation of molasses by Saccharomyces. It is a type of alcohol and is a clean (smokeless) fuel. It is mixed with petrol and diesel to prevent vehicular emissions.
- Methane: Methane is a gaseous fuel that is obtained by microbial anaerobic decomposition of urban, agricultural, and industrial waste.
- Hydrogen fuel: Hydrogen is released during the bio-photolysis of water, in which bacteria perform photoreduction. It is considered the fuel of the future as it is non-polluting and an efficient fuel.
Fuels obtained from fossil sources are non-renewable and polluting. In contrast, fuels such as hydrogen, ethanol, and methane represent the future of energy because they burn cleaner, offer comparable efficiency, and are renewable. Therefore, their use should be further promoted.
b. How can the oil spills of rivers and oceans be cleaned?
Answer:
i. Spilling of petroleum oil occurs in ocean due to various reasons.
ii. This oil may prove fatal and toxic to aquatic organisms.
iii. It is not easy to remove the oil layer from surface of water by mechanical method. However, bacteria like Pseudomonas spp. and Alcanovorax borkumensis have the ability to destroy the pyridines and other chemicals.
iv. Hence, these bacteria are used to clear the oil spills. These are called as hydrocarbon clastic bacteria (HCB). HCB decompose the hydrocarbons and bring about the reaction of carbon with oxygen. CO2 and water is formed in this process.
c. How can the soil polluted by acid rain be made fertile again?
Answer:
- The soil polluted by the acid rain is made fertile again by using bacteria.
- Acidophillium spp. and Acidobacillus ferroxidens are the bacteria which have the capacity to use sulphuric acid as their energy source.
- Since this sulphuric acid present in the acid rain, can be controlled by these bacteria.
- In this way, bacteria can control the soil pollution occurring due to acid rain, making the soil fertile again.
d. Explain the importance of bio pesticides in organic farming.
Answer:
- By using bio pesticides, soil pollution is minimized. Otherwise by using chemical pesticides and fertilizers there is large scale soil pollution.
- When chemical pesticides are used in agriculture, there is contamination of soil by fluoroacetamide – like chemicals.
- These are harmful to other plants, animals as well as for-human beings. They may cause skin diseases in humans.
- By using bacterial and fungal toxins the pests and pathogens can be destroyed. Such toxins are directly incorporated in the plant materials.
E.g. Spinosad is a biopesticide produced as a by-product of fermentation.
e. What are the reasons for increasing the popularity of probiotic products?
Answer:
Probiotics are such edible preparations which contain useful active bacteria, like Lactobacillus, Acidophilus, Lactobacillus casei, Bifidobacterium bifidum, etc. There are various reasons for which probiotics are being promoted nowadays. These bacteria are beneficial for the intestine as they help in the process of metabolism. They are usually given when a person is suffering from diarrhoea or is under antibiotic treatment. Antibiotics kill both beneficial and harmful bacteria present in our body, thus affecting the metabolic process. These probiotics form the colonies of useful microbes in the alimentary canal and thus aid in the digestion process.
f. How the bread and other products produced using baker’s yeast are nutritious?
Answer:
- In order to make the bread the baker’s yeast – Saccharomyces cerevisiae is added to the flour for the fermentation process.
- In commercial bakery, compressed yeast is used while in domestic settings dry, granular form of yeast is used.
- The flour prepared by using commercial yeast contains various useful contents like carbohydrates, fats, proteins, various vitamins, and minerals.
- The anaerobic fermentation also increases the nutritive content of the flour.
- Due to this, bread and other products produced with the help of yeast become nutritive.
g. Which precautions are necessary for proper decomposition of domestic waste?
Answer:
Domestic waste refers to the waste which is generated in our houses due to our daily activities. Domestic waste can be either biodegradable or non-biodegradable for example, vegetable and fruit peels are biodegradable whereas batteries, computers, etc are non-biodegradable. biodegardable products can be used for making composts which can be used in parks, plant pots etc. For non-biodegradable products, we need to practice the 3R’s, and only after that, they should be discarded as waste. The 3R’s are –
- Reduce- Reduce the amount of waste produced.
- Reuse- Reusing a resource in a new way before throwing it.
- Recycle- Making something new from a material rather than throwing it away.
h. Why is it necessary to ban the use of plastic bags?
Answer:
Plastic bags are non biodegradable products which pose a serious threat to the environment. Non biodegradable products do not decompose easily and thus keep on accumulating in the environment. There are various other reasons for which plastic bags should be banned, for example:
- plastic bags, on getting into drains and sewer system, choke them up resulting in spilling of dirty water on the roads
- burning of plastic bags produces harmful gases, which can cause health problems
- street animals may consume these plastic bags, which may even result in their deaths.
Complete the following conceptual picture.
Give scientific reasons.
Answer:
- By using industrial microbiology, the commercial use of microbes is done.
- In such experiments, various economic, social and environment related processes and products are included.
- In this, fermentation processes are used to make bread, cheese, wines, enzymes, nutrients, etc.
- Different types of antibiotics are also made by using processes of industrial microbiology.
- In pollution control and solid waste management, the industrial microbiology becomes helpful.
- In farming too biotechnology is used to produce BT crops.
b. Enzymes obtained by microbial process are mixed with detergents.
Answer:
- When detergents are mixed with microbial enzymes, they start working more efficiently.
- The cleaning process takes place at lesser temperatures.
- Therefore, for better results, enzymes obtained by microbial process are mixed with detergents.
c. Microbial enzymes are used instead of chemical catalysts in chemical industry.
Answer:
- These enzymes are active at low temperature, pH and pressure; due to which energy is saved and erosion-proof instruments are also not necessary.
- Enzymes carry out specific processes; hence unnecessary byproducts are not formed due to which expenses on purification are minimized.
- In the case of microbial enzymatic reactions, elimination and decomposition of waste material are avoided and enzymes can be reused. Hence, such enzymes are eco-friendly.
Question 6.
Complete the following conceptual picture with respect to its uses.
Answer:
Question 7.
Complete the following conceptual picture related to environmental management.
Answer:
Question 8.
Answer the following questions.
a. What is the role of microbes in compost production?
Answer:
- Microbes can bring about natural decomposition of the organic compounds.
- During the biodegradation, some bacteria andmfungi bring about such decomposition and release the inorganic constituents back into the nature.
- Compost is formed in such a way by recycling process.
b. What are the benefits of mixing ethanol with petrol and diesel?
Answer:
Whenever ethanol is mixed with petrol and diesel, CO2 emission from automobiles reduces by 30%. As a result, pollution decreases. Ethanol, when mixed with petrol and diesel, serves as a great cleaning agent for car engines over a long run. It also helps to increase and improve the quantity of fuel.
c. Which plants are cultivated to obtain the fuel?
Answer:
- The ethanol is obtained from wheat, maize, beet, sugarcane and molasses of sugarcane.
- For biodiesel, the soybean, rapeseed, jatropa, mahua, flaxseed, mustard, sunflower, palm, jute and some types of algae are cultivated.
d. Which fuels are obtained from biomass?
Answer:
From biomass, the biogas and biodiesel are mainly obtained. The biogas is obtained from dung of cattle. The fermentation of cattle dung gives rise to methane. From methane, methanol is obtained. Ethanol is obtained from molasses of sugarcane and some other crops. In some countries, special crops are cultivated for the biodiesel.
e. How does the bread become spongy?
Answer:
- When the dough for bread is prepared, the baker’s yeast – Saccharomyces cerevisiae is added to it.
- This yeast carries out anaerobic fermentation.
- This results in formation of CO2 and ethanol.
- The CO2 formed tries to escape out of the flour and thus the dough rise. When such dough is baked, it produces spongy bread.
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