BT402 Final Term Solved Past Papers

Q4. Soil treatment?

• All the bio fertilizers along with the compost fertilizers are mixed together.
• They are kept for one night. Then the next day the mixture is spread on the soil where

seeds have to be sown.

Q5. role of microbes in petroleum industry?

Petroleum-based products are the major source of energy for industry and daily life. Leaks and accidental spills occur regularly during the exploration, production, refining, transport, and storage of petroleum and petroleum products. • Release of hydrocarbons into the environment whether accidentally or due to human activities is a main cause of water and soil pollution

• Soil contamination with hydrocarbons causes extensive damage of local system since accumulation of pollutants in animals and plant tissue may cause death or mutations
• Microbial processes play an important role in industry, the protection of the natural environment
• Several practical applications of microbial processes are listed as follows

Bioremediation • Bioremediation is a natural process that involves the use of biological entities to neutralize the contaminated site

• Microbial biodegradation is the use of bioremediation and biotransformation methods to harness the naturally occurring ability of microbial xenobiotic metabolism to degrade, transform or accumulate environmental pollutants, including hydrocarbons (e.g. oil), polychlorinated biphenyls (PCBs), polyaromatic hydrocarbons

Biosurfactants • These are microbial-synthesized surface-active substances that allow for more efficient microbial biodegradation of hydrocarbons in bioremediation processes.

• There are two ways by which biosurfactants are involved in bioremediation
• 1) Increase the surface area of hydrophobic water-insoluble substrates. Growth of microbes on hydrocarbons can be limited by available surface area of the water-oil interface. Emulsifiers produced by microbes can break up oil into smaller droplets, effectively increasing the available surface area.
• 2) Increase the bioavailability of hydrophobic water-insoluble substrates. Biosurfactants can enhance the availability of bound substrates by desorbing them from surfaces (e.g. soil) or by increasing their apparent solubility. Some biosurfactants have low critical micelle concentrations (CMCs), a property which increases the apparent solubility of hydrocarbons by sequestering hydrophobic molecules into the centres of micelles.
• Microbial Enhanced Oil Recovery (MEOR) • One of the major concerns facing the oil industry today is the recovery of the large percentage of oil remaining unrecovered in mature and in nearly depleted oil fields.

Q6. Live attnuated vaccine?example? (3)

Q7. Steps of vacine production?

The production of a vaccine can be divided in the following steps:

1. Generation of the antigen

The first step in order to produce a vaccine is generating the antigen that will trigger the immune response. For this purpose the pathogen’s proteins or DNA need to be grown and harvested using the following mechanisms:

Viruses are grown on primary cells such as cells from chicken embryos or using fertilised eggs (e.g. influenza vaccine) or cell lines that reproduce repeatedly (e.g. hepatitis A)

Bacteria are grown in bioreactors which are devices that use a particular growth medium that optimises the production of the antigens

Recombinant proteins derived from the pathogen can be generated either in yeast, bacteria or cell cultures.

2. Release and isolation of the antigen

The aim of this second step is to release as much virus or bacteria as possible. To achieve this, the antigen will be separated from the cells and isolated from the proteins and other parts of the growth medium that are still present.

3. Purification

In a third step the antigen will need to be purified in order to produce a high purity/quality product.