Microbes In Human Welfare

Step 1: Understanding the Concept:
Antibiotics are biological products used in medicine to treat bacterial infections.
Step 2: Detailed Explanation:
The term 'Antibiotic' (Greek: anti = against; bios = life) refers to substances that act against life (pathogenic bacteria).
They are naturally produced by certain microbes (like Penicillium mold or Streptomyces bacteria) to inhibit the growth of competing microorganisms.
They are effective against bacteria but not against viruses.
Step 3: Final Answer:
True.

Step 1: Discharging untreated sewage increases the organic matter in the water, which leads to a sharp increase in the Biochemical Oxygen Demand (BOD).
Step 2: Microorganisms consume the dissolved oxygen to decompose the organic waste, leading to a decline in Dissolved Oxygen (DO).
Step 3: This lack of oxygen results in the mass mortality of fish and other aquatic organisms, and the water becomes a source of waterborne diseases like Cholera.

Step 1: Cyclosporin A is a bioactive molecule that inhibits the T-cell mediated immune response.
Step 2: It is used to prevent the patient's body from rejecting a newly transplanted organ.
Step 3: It is extracted commercially from the fungus Trichoderma polysporum.

Step 1: *Aspergillus niger* is a fungus (specifically a black mold).
Step 2: It is widely used in the food and beverage industry for the large-scale production of Citric acid.
Step 3: For comparison: *Acetobacter aceti* produces Acetic acid, *Lactobacillus* produces Lactic acid, and *Clostridium butylicum* produces Butyric acid.

Step 1: Understanding the Concept:
Lactic Acid Bacteria (LAB), such as Lactobacillus, are responsible for the fermentation of milk into curd.
Step 2: Detailed Explanation:
During growth, LAB produce acids that coagulate and partially digest the milk proteins (casein).
This process not only changes the texture and taste but also significantly enhances the nutritional value of the milk.
The most notable nutritional improvement is the increase in the concentration of Vitamin .
Additionally, LAB in the human stomach play a beneficial role in checking disease-causing microbes.
Step 3: Final Answer:
The conversion of milk to curd increases the content of Vitamin .

In this process, anaerobic bacteria digest the bacteria and fungi present in the activated sludge. This is important because it significantly reduces the sludge volume and produces biogas (a mixture of methane, hydrogen sulfide, and ), which can be used as fuel.

Step 1: Curd formation - Microorganisms like Lactobacillus and others commonly called Lactic Acid Bacteria (LAB) grow in milk and convert it into curd by producing acids that coagulate and partially digest milk proteins.
Step 2: Fermentation in Dough - The dough used for making foods like dosa and idli is fermented by bacteria. Similarly, Saccharomyces cerevisiae (Baker’s yeast) is used to ferment dough for making bread, giving it a puffed-up appearance due to production.
Step 3: Other uses - Microbes are used to ferment fish, soybean, and bamboo shoots to make tasty foods. Different varieties of cheese, like Swiss cheese, are formed due to the production of large amounts of by bacteria like Propionibacterium sharmanii.

Step 1: Understanding the Concept:
Methanogens are anaerobic bacteria commonly found in anaerobic sludge during sewage treatment and in the rumen of cattle.
Step 2: Detailed Explanation:
1. Anaerobic Digestion: These bacteria grow anaerobically on cellulosic materials present in organic waste (like cow dung/gobar).
2. Production of Gases: During their metabolic activity, they produce large amounts of methane ( ) along with carbon dioxide ( ) and hydrogen ( ).
3. Biogas Generation: This mixture of gases is highly inflammable and is collectively called biogas.
4. Example: Methanobacterium is a common genus involved in this process.
Step 3: Final Answer:
Methanogens decompose organic matter in the absence of oxygen to release methane-rich biogas, used as a renewable energy source.