1. Scaling up of batch sterialisation

2. Batch culture: Growth Kinetics
During log phase growth reaches maximum (max)
After depletion of substrate, growth rate decreases and finally ceases
m = m max s
(Ks +s)
m= specific growth rate m
m max
1/2 m max
Ks = substrate concentration
Residual substrate conc. [s]

3. As growth increases biomass increases: during log phase
dx = mx dt
dx. 1 = m
dt x 1
x = cell conc (biomass) (mg/m3)
t = incubation time (h)
m = specific growth rate (h-1) dx dt
m =slope x

4. Beginning of log phase t=0 biomass X0
On integration of equation 1
∫dx = ∫ mx x
Loge X = mt + K (integration constant)
when t=0
Log X0 = K put this value in equation 2
loge X = mt + loge X0
Loge X –loge X0 = mt
ln X = mt X0
ln X . 1 = td
X0 m 2 3

5. When t = td
X = 2X0
Then ln X . 1 = td
X0 m
ln 2X = td
X m
ln 2 = td m
0.693 = td
m is inversely proportional to td
If td is high m is low and vice versa m
= 0.693 td

6. X0 cells inoculated at time t0
X cells at time t
dx = mx Can be written as equation 3 dt
ln X = mt X0
ln X –ln X0 = mt
Converting natural log
(log10 X –log10 X0) = mt
(log10 X –log10 X0) = tt-t0 m
(log10 X –log10 X0) = m
tt-t0

7. m max = m max s (Ks +s) m= specific growth rate m
Ks = substrate concentration
Residual substrate conc. [s]

8. Disadvantages of batch cultures
Temperature of batch culture cannot be increased beyond 121oC
In case increased
Heating & cooling periods will increase
Degradation of nutrients
Problem overcomed by switching to continious sterialisation because
Media to be sterialised is dealth in small increments
Shorter heating & cooling period
Lesser nutrient degradation

9. Development of industrial fermentation processes
Money making
Competition
Economically feasible on large scale basis
Recovery of product ready for open market
Competitive advantage

10. What are the R&D approaches for finding of a MO of economic value, and large scale fermentation process?
Micro-organism
Source
Stock culture collections
Environment (soil)
Screening
Primary screening
Secondary screening

11. Preservation of Industrially important MO
Viable and Free from contamination
Stored in such a way so as to eliminate genetic change and retain viability
Viable by repeated sub-culture (avoid mutations by keeping stocks and strain degeneration and contaminations)

12. Preservation of Industrially important MO
Storage at reduced temperature
Agar slopes at 50C or in -200C freezer: viable for 6 months
Liquid nitrogen (-1960C): problems of refilling, advantages
Storage at dehydrated form
Dried cultures
Lyophillization
Quality control of preserved stock: batch system, single colony, typical pattern, large number, purity, viability and productity
If sample fails entire batch is destroyed

13. Types of Low molecular weight compounds by MO
SUBSTRATE
Primary
metabolites
Secondary
metabolites
Bioconversions
Steroids
Amino acids
Ascorbic acid
Antibiotics
Alkaloids
Gibberlins
Pigments
Essential metabolites
Amino acids
Nucleosides
vitamins
Metabolic end products
Ethanol, acetone, lactic acid, butanol