TOPIC 5

Question 1

Biotechnology

Answer 1

Technological application that uses biological systems, living organisms for modifying human health and environment

Question 2

Recent Developments in Biotechnology

Answer 2

Medicine (antibiotics), Agriculture (plant tissue culture), Chemicals (organic acids), Environment (replacement of chemical insecticides), Food (single cell protein), and Industry (enzymes in detergent industry)

Question 3

Screening of Microorganisms: Amylase

Answer 3

Starch-Agar method

Question 4

Screening of Microorganisms: Protease

Answer 4

Precipitation test

Question 5

Screening of Microorganisms: Antibiotics

Answer 5

Primary: crowded plate technique
Secondary: Specialized tests

Question 6

Screening of Microorganisms: Amino Acids

Answer 6

Auxanography

Question 7

Primary Screening of Antibiotics include:

Answer 7

the crowded plate method; the direct-soil-inoculation method; the cross-streak method; the agar plug method; and the replica plating method

Question 8

General techniques for the selection of microorganisms

Answer 8

Chemical: the use of special nitrogen or carbon source; the use of toxic or inhibitory substances

Physical: Heat treatments (80*C for 10 mins); incubation temperature; pH of the medium (useful for yeasts and molds); and cell size and motility

Question 9

Upstream process

Answer 9

all the operations before starting the fermenter

Question 10

the upstream process includes:

Answer 10

A) Producer microorganism; suitable, strain improvement to increase productivity, maintenance of strain purity, prep for inoculum

B) fermentation media and fermenter; prep and sterilization of culture medium and sterilization of fermenter

Question 11

Downstream process

Answer 11

all the operations after the fermentation

Question 12

the operations of the downstream process include:

Answer 12

cell harvesting; cell disruption; and product purification from cell extracts or the growth medium

Question 13

methods commonly used in downstream process

Answer 13

distillation; centrifugation; filtration; solvent extraction

Question 14

What is meant by Fermentor (bioreactor)?

Answer 14

a vessel for the growth of microorganisms; not permitting contamination; enabling the provision of conditions necessary for max production of products

Question 15

What is scale-up?

Answer 15

the transfer of small scale laboratory fermentation to an industrial large scale; without loss of characteristics

Question 16

Classifications of Bioreactors

Answer 16

Configuration: open, closed

Biomass retention mode: Suspended, immobilized

Flow within the bioreactor: well mixed, plug flow

Mode of operation: batch, fed-batch, continuous

Question 17

Batch fermentation

Answer 17

nothing is added to the fermenter during fermentation process except air, an antifoam agent, acid or alkali to control the pH

Question 18

Fed-Batch process

Answer 18

Sterile nutrients are added at intervals as the fermentation progresses

Question 19

Continuous fermentation

Answer 19

sterile nutrients are added continuously to the fermenter and equivalent amount of products with microorganisms are simultaneously harvested out of the fermenter

Question 20

Bacterial growth curve dynamics;

Answer 20

1. Lag phase
2. log phase
3. stationary phase
4. death phase

Question 21

Lag phase

Answer 21

population initially doesn’t grow; cells are getting ready for division

Question 22

Exponential (log) phase

Answer 22

population doubles according to generation time; most experiments are done during this time; cells are active

Question 23

stationary phase

Answer 23

population remains constant; nutrients are depleted from; cells are less active

Question 24

Death phase

Answer 24

population decreases exponentially (but slower); nutrients are almost gone, waste products are high

Question 25

Application of fermentation

Answer 25

production of microbial cells as the products; production of microbial metabolites; production of microbial enzymes; modification of a compound; those the produced recombinant products

Question 26

Single Cell Protein (SCP)

Answer 26

SCP are dried cells of microorganisms; can be used as dietary protein supplement

Question 27

Production of SCP

Answer 27

Selection of suitable strain; fermentation; harvesting; post harvest treatment; processing of SCP for food

Question 28

Advantages of SCP

Answer 28

rapid growth rate and high productivity; high protein of dry mass; consistent quality; utilization of solar energy

Question 29

Disadvantages of SCP

Answer 29

high nucleic acids lead to elevated levels of uric acid