Solutions-Class 10-Science & Technology-2-Chapter-7-Introduction to Microbiology-Maharashtra Board

(i). Process of coagulation of milk proteins occurs due to lactic acid.

(ii). Harmful bacteria in like Clostridium in the intestine are destroyed due to probiotics.

(iii). Chemically, vinegar is acetic acid.

(iv). Salts which can be used as supplement of calcium and iron are obtained from gluconic acid.

There are different kinds of fuel which can be produced with the help of microbes. Some of the examples of such fuels are:

• Ethanol- It is a byproduct which is produced during fermentation of molasses by treating with Saccharomyces-yeast. It is a type of alcohol and is a clean (smokeless) fuel. It is mixed with petrol and diesel to prevent vehicular emission.
• Methane- Methane is a gaseous fuel which is obtained by microbial anaerobic decomposition of urban agricultural and industrial waste.
• Hydrogen fuel: By photoreduction of water with the help of Bacteria, Hydrogen gas is released in the bio-photolysis of water process. It is considered as the fuel of future as it is non polluting and an efficient fuel.

Fuels which are obtained from fossil fuels are exhaustible, and also polluting. These fuels like hydrogen, ethanol, methane are the future fuels as they burn cleaner with more less same efficiency and are renewable. Thus, their use needs to be promoted further.

• Oil spills are a form of pollution in which liquid fuels, like petroleum are spilled on water, land or air.
• Oil spills usually occur in oceans where there is accidental leakage of oil.
• Oil is toxic and harmful to the aquatic life as it reduces the availability of oxygen and would eventually result in their death.
• It is difficult to clear out oil spills by mechanical means, this methods are not much efficient and take a lot of time.
• To overcome this issue, a new approach has been developed which uses bacteria known as hydrocarbonoclastic bacteria (HCB) to remove this pollution.
• These group of bacteria are capable of degrading pyrimidines and other chemicals.
• They convert hydrocarbons to CO₂ and oxygen. Pseudomonas sp. and Alcanovorax borkumensis are used for this purpose.

• The sulphuric acid which is a part of acid rain and is released from various industries is a common pollutant of soil.
• Soil which has been polluted by sulphuric acid cannot be used for cultivation of plants.
• However, there is a way of treating this soil to make it fertile again.
• The polluted Soil is made fertile again by using bacteria.
• Microorganisms like Acidophillium sp. and Acidobacillus ferroxidens can be used in the treatment of soil polluted with sulphuric acid.

By using bio pesticides, the problem of soil pollution does not exist. 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.

Biopesticide is a term used for bacterial and fungal toxins which can be used to destroy pests/pathogens/insects and can be directly integrated into the plants.

Examples of biopesticides are-

• Bacillus thuringiensis(Bt) is used to control butterfly caterpillars. This bacterium is available in sachets as dried spores, which are sprayed on the crops. The spores get into the gut of the larvae and kill it while the other insects remain unperturbed.
• The fungus Trichodermaliving in roots of plants acts as a biocontrol agent against several plant pathogens.

• Baculoviruses, particularly genus Nucleopolyhedrovirus are also used as narrow spectrum insecticidal agents.  
• A by-product of fermentation called Spinosad is a biopesticide.

• Probiotics are such edible preparations which contain useful active bacteria, like Lactobacillus, Acidophilus, Lactobacillus casei, Bifidobacterium bifidum, etc.
• Probiotic substances are mostly milk products containing live bacteria. These probiotics are very good for health.
• These bacteria are beneficial for the intestine as they help in the process of metabolism.
• Probiotics decreases the population of harmful microbes like clostridium from our digestive track.
• 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 alimentary canal and thus aid in the digestion process.

• Baker's yeast is commonly used in food production.
• It's major application is in the food industry where it is used in various baking procedures as well as for fermentation purposes.
• Fermentation of fruit juices, maple syrup, sugar molasses etc. with the help of yeast yields ethanol.
• It is used in baking breads and other products as it provides them with a fluffy and spongy characteristic.
• The flour prepared by using commercial yeast contains various useful contents, like carbohydrates, fats, proteins
• Apart from this, yeast is also a rich source of  various vitamins, and minerals.

Due to this bread and other products produced using baker’s yeast are nutritious?

• 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.
• The non-biodegradable things such as plastic articles, glass pieces, metal objects, unused medicines, e-waste should never be thrown in wet wastes
• Use 3R method for non-biodegradable waste.
  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.
• The toxic substances and the insecticides if added to wet waste, will never allow the natural decomposition process.

Therefore, only after taking proper precautions we can aim at proper decomposition of domestic wastes.

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.

• Mutant microorganisms have characteristics which are not present in the original strain and thus make them useful for various purposes.
• By using industrial microbiology, the commercial use of microbes is done. In such
  experiments, various economic, social and environment related processes and products are
• Various processes using different microbes are done. 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 also biotechnology is used to produce BT crops.

Enzymes obtained by microbial process are mixed with detergents because it makes the cleaning process efficient. Addition of enzymes to detergents makes them efficient in removing dirt with an added advantage of efficiently work at lower temperatures.

Microbial catalysts are also known as biocatalysts. Microbial catalysts are preferred over chemical catalysts for various reasons like:

• No unnecessary byproducts are  formed in case of microbial enzymes which means the expenses on purification is minimized.
• Microbial enzymes can function at low temperatures, pH and pressure, thus saving the energy.
• Enzymes which are used in these processes can be reused as they do not decompose during these processes.
• Use of enzymes also reduces the amount of environmental pollution.

Microbes play an important role in various aspects of our lifes.

• One such important role is the formation of compost.
• Microbes can do natural decomposition of the organic compounds.
• The biodegradable waste which is collected from all around the cities are placed in landfill sites. The conversion of this waste is then carried out by various kinds of microorganisms, specially aerobic bacteria and some kind of fungi.
• It brings decomposition and release the inorganic constituents back into the nature.
• It takes time for formation of compost and then the landfill site is again ready to use while the compost can be used in agricultural fields, parks etc.

• If only petrol or diesel use as a fuel, there is increased air pollution.
• Nowadays, many countries are practicing mixing of ethanol with petrol and diesel.
• Ethanol is a clean burning fuel and reduces the vehicle exhaust emissions.
• Ethanol burns more efficiently
• it is an easily available and cheap source therefore cost of fuel is also less.

• Biofuels can be obtained from cultivating plants like corn, sugarcane, palm oil, jatropha, soybean, switchgrass and rapeseed.
• Ethanol obtained from wheat, maze, beet, and molasses of sugarcane.
• Biodiesel obtained from soybean, palm, jute and some types of algae.

• Fuels which are obtained from biomass are called bio fuels and they are an important and renewable source of energy.
• Mainly Biogas and bio diesel obtained from biomass.
• Biofuels can be in the form of either solid, liquid or gases.
  Solid biofuels- coal, dung, crop residue
  Liquid- vegetable oils, alcohol
  Gaseous- gobar gas, coal gas

Breads become spongy due to the addition of yeast in their dough. Yeast reproduces rapidly and produces carbon dioxide gas while respiring. This gas fills the dough and increases its volume making it to rise, thus making the bread appear spongy and fluffy.