TOPIC 5 Flashcards
Biotechnology
Technological application that uses biological systems, living organisms for modifying human health and environment
Recent Developments in Biotechnology
Medicine (antibiotics), Agriculture (plant tissue culture), Chemicals (organic acids), Environment (replacement of chemical insecticides), Food (single cell protein), and Industry (enzymes in detergent industry)
Screening of Microorganisms: Amylase
Starch-Agar method
Screening of Microorganisms: Protease
Precipitation test
Screening of Microorganisms: Antibiotics
Primary: crowded plate technique
Secondary: Specialized tests
Screening of Microorganisms: Amino Acids
Auxanography
Primary Screening of Antibiotics include:
the crowded plate method; the direct-soil-inoculation method; the cross-streak method; the agar plug method; and the replica plating method
General techniques for the selection of microorganisms
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
Upstream process
all the operations before starting the fermenter
the upstream process includes:
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
Downstream process
all the operations after the fermentation
the operations of the downstream process include:
cell harvesting; cell disruption; and product purification from cell extracts or the growth medium
methods commonly used in downstream process
distillation; centrifugation; filtration; solvent extraction
What is meant by Fermentor (bioreactor)?
a vessel for the growth of microorganisms; not permitting contamination; enabling the provision of conditions necessary for max production of products
What is scale-up?
the transfer of small scale laboratory fermentation to an industrial large scale; without loss of characteristics
Classifications of Bioreactors
Configuration: open, closed
Biomass retention mode: Suspended, immobilized
Flow within the bioreactor: well mixed, plug flow
Mode of operation: batch, fed-batch, continuous
Batch fermentation
nothing is added to the fermenter during fermentation process except air, an antifoam agent, acid or alkali to control the pH
Fed-Batch process
Sterile nutrients are added at intervals as the fermentation progresses
Continuous fermentation
sterile nutrients are added continuously to the fermenter and equivalent amount of products with microorganisms are simultaneously harvested out of the fermenter
Bacterial growth curve dynamics;
- Lag phase
- log phase
- stationary phase
- death phase
Lag phase
population initially doesn’t grow; cells are getting ready for division
Exponential (log) phase
population doubles according to generation time; most experiments are done during this time; cells are active
stationary phase
population remains constant; nutrients are depleted from; cells are less active
Death phase
population decreases exponentially (but slower); nutrients are almost gone, waste products are high
Application of fermentation
production of microbial cells as the products; production of microbial metabolites; production of microbial enzymes; modification of a compound; those the produced recombinant products
Single Cell Protein (SCP)
SCP are dried cells of microorganisms; can be used as dietary protein supplement
Production of SCP
Selection of suitable strain; fermentation; harvesting; post harvest treatment; processing of SCP for food
Advantages of SCP
rapid growth rate and high productivity; high protein of dry mass; consistent quality; utilization of solar energy
Disadvantages of SCP
high nucleic acids lead to elevated levels of uric acid
