Tag: biotechnology

Questions Related to biotechnology

Single cell protein refers to

  1. Specific protein extracted from pure culture of single type of cells.

  2. Sources of mixed proteins extracted from pure or mixed culture of organisms or cells.

  3. Proteins extracted from a single cell.

  4. A specific protein extracted from a single cell.


Correct Option: B
Explanation:

Single-cell protein refers to sources of mixed protein extracted from pure or mixed cultures of algae, yeasts, fungi or bacteria (grown on agricultural wastes) used as a substitute for protein-rich foods, in human and animal feeds.

Stirred-tank bioreactors have been designed for

  1. Availability of oxygen throughout the process

  2. Addition of preservation to the product

  3. Purification of the product

  4. Ensuring anaerobic conditions in the culture vessel


Correct Option: A
Explanation:

In stirred tank bioreactors, the oxygen mass transfer is a function of many variables, such as the physical properties of the liquid (viscosity, surface tension, etc.), the geometry of the vessel and stirrer and the operational conditions. In the stirred-tank bioreactor, the stirrer facilitates even mixing and oxygen availability throughout the bioreactor. 

Monascus purpureus is a yeast used commercially in the production of 

  1. Ethanol

  2. Streptokinase for removing clots from the blood vessels

  3. Citric acid

  4. Blood cholesterol lowering statins


Correct Option: D
Explanation:

Red yeast is used for maintaining desirable cholesterol levels in healthy people. The active ingredient in red yeast is the same as the active ingredient in prescription drugs called statins used for high cholesterol. Thats why, red yeast has all the possible side effects, drug interactions, and precautions associated with this type of drug.

Which one of the following is a wrong matching of a microbe and its industrial product?

  1. Clostridium butylicum - lactic acid

  2. Aspergillus niger - citric acid

  3. Yeast - statins

  4. Acetobacter aceti - acetic acid


Correct Option: A
Explanation:

The bacterium Clostridium acetylbutylicum, easliy converts any fermentable sugar to butanol and additionally produces hydrogen gas, acetone, isopropyl alcohol. Isopropanol is a product of the organism formerly known as Clostridium butylicum, which is now included in the species Clostridium beijerinckii

The most common substrate used in distilleries for the production of ethanol is

  1. Molasses

  2. Corn meal

  3. Soya meal

  4. Ground gram


Correct Option: A
Explanation:

Molasses are used commonly in distilleries for ethanol production. Saccharomyces cerevisiae is an industrial yeast possessing most of the desirable fermentation characteristics like fast growth and fermentation rate, osmo-tolerance, high ethanol tolerance, ability to ferment molasses, and to ferment at elevated temperatures etc.

The fruit juices turn bitter in taste if they are kept in open place for sometime, because of

  1. Bacteria of the atmosphere react with the juice.

  2. Fermentation of the juice by yeast.

  3. Some internal factors.

  4. All the above three statements are correct.


Correct Option: B
Explanation:

Raw fruit juice is usually a strongly acidic solution, containing from 10 to 25 percent soluble sugars. Its acidity and high sugar concentration make it an unfavourable medium for the growth of bacteria but highly suitable for yeasts and moulds. Raw fruit juice naturally contains many yeasts, moulds, and bacteria, derived from the surface of the fruit. Normally, the yeast used in alcoholic fermentation is a strain of the species Saccharomyces cerevisiae

The bread is soft and porous when the yeast cells are mixed in the lump of wheat flour because

  1. Yeast produce benzoic acid.

  2. Evolution of $CO _{2}$makes the bread spongy.

  3. Yeast is soft and flour also becomes soft.

  4. Yeast produces acetic acid and alcohol which give softness to the bread.


Correct Option: B
Explanation:

When yeast is added to a mixture of dough, a fermentation process begins as the yeast eats the sugars and releases carbon dioxide gas. The yeast absorbs the oxygen in the dough as it begins a reproduction of cells, dividing the single yeast cell into two cells, which then become four, and redividing continuously into increasingly larger numbers of cells. Trapped in the dough, the yeast cells produce carbon dioxide resulting in the rising of the dough until it reaches a point in size to be burst, reducing it back into its original shape to begin the rising process again. This second rising is faster due to the abundance of cells now present from multiplying continuously.

The method of producing proteins for food or feed through microbial biomass is called as:

  1. PCR (Polymerase Chain Reaction)

  2. SCP (Single Cell Protein)

  3. Nanotechnology

  4. None of the above


Correct Option: B
Explanation:
  • Single-cell proteins refer to edible unicellular microorganisms. 
  • The biomass or protein extract from pure or mixed cultures of algae, yeasts, fungi or bacteria may be used as an ingredient or a substitute for protein-rich foods and is suitable for human consumption or as animal feeds. 
  • Hence, The method of producing proteins for food or feed-through microbial biomass is called as SCP (Single Cell Protein).
  • So, the correct answer is 'SCP (Single Cell Protein)'.

Which of the following statement regarding SCP is incorrect?

  1. Contains carbohydrates and fats.

  2. SCP obtained from algae and fungi.

  3. Commercial SCP is based on mainly yeast and fungi.

  4. Substrate for SCP is saw dust, paddy and straw.


Correct Option: A
Explanation:

Single-cell protein (SCP) refers to sources of mixed protein extracted from pure or mixed cultures of algae, yeasts, fungi or bacteria (grown on agricultural wastes) used as a substitute for protein-rich foods, in human and animal feeds. Single-cell proteins develop when microbes ferment waste materials including wood, straw, cannery and food-processing wastes, residues from alcohol production, hydrocarbons, or human and animal excreta.

Vitamin $B _{12}$ is produced directly during the course of fermentation by

  1. Ashbya gossypii

  2. Rhizopus stolonifer

  3. Saccharomyces cerevisiae

  4. Propionibacteria


Correct Option: D
Explanation:

It has been demonstrated that Propionibacteria species has the highest potential to accumulate vitamin B$ _{12}$ intracellularly. Propionibacterium shermanii and Propionibacterium freudenreichii are most widely used. Propionibacteria produce vitamin B$ _{12}$ intracellularly and excrete mainly propionic acid and acetic acid extracellularly. All Propionibacterium strains employed for vitamin B$ _{12}$ production are microaerophilic and produce vitamin B$ _{12}$ in high yields only under very low oxygen concentrations.

Thus, the correct answer is option D.