Lyophilization, also known as freeze drying, is a process that removes water from a material through sublimation while preserving its structure and composition. It works by first freezing the material and then reducing the pressure and increasing the temperature to allow the frozen water to change directly from solid to gas without passing through the liquid phase. A simple lyophilizer freezes materials on heated shelves, lowers the chamber pressure to 0.06 atmospheres using a vacuum pump, causing the frozen water to sublimate into a gas and condense on a freezing coil outside the chamber. Lyophilization is used to preserve bacterial and viral cultures, dry numerous products, and store water-damaged materials like manuscripts.

1. PRINCIPLES AND
APPLICATIONS
YEAR: 2016-2017
LYOPHILIZATION: FREEZE DRYING
SUDHIR KUMAR
M.Sc.
MICROBIOLOGY
3RD SEMESTER
DSMNRU, LUCKNOW

2. What is Lyophilization?
• Process of completely removing water(dehydration)
from some material such as food while leaving the
basic structure and composition of material in tact.
• Lock the composition and structure of the material
by drying on molecular level.
• Freeze drying process converts ice into water
vapour skipping the liquid phase entirely.

3. PRINCIPLE OF
LYOPHLIZATION
• MAIN PRINCIPLE:
SUBLIMATION.
• TRIPLE POINT: EQUILIBRIUM
PHASE OF WATER.
• SUBLIMATION TAKES PLACE
WHEN TEMPRATURE IS
RAISED ABOVE 32 DEG. F
KEEPING THE PRESSURE
BELOW 1 ATM.
• SOLID PHASE WATER IS WARM
ENOUGH BUT THERE IS NO
ENOUGH PRESSURE FOR
LIQUID TO FORM. IT BECOMES
A GAS.

4. A SIMPLE
LYOPHILIZER
1) MATERIAL IS KEPT IN HEATED
SHELVES. DOOR CLOSED.
2) START THE TEMPRATURE TO
LOWER THE CHAMBER
TEMPRATURE TO MAKE MATERIAL
FROZEN SOLID.
3) VACCUM PUMP FORCES AIR OUT OF
THE CHAMBER LOWERING
ATMOSPHERIC PRESSURE UPTO
0.06.
4) PRESSURE IS LOW SO FROZEN
SOLID CHANGES TO WATER
VAPOUR.
5) WATER VAPOUR FLOW FROM THE
SHELF IN FREEZE DRY CHAMBER
AND CONDENSES ON FREEZING
COIL IN SOLID ICE FORM.

5. APPLICATION OF
LYOPHLIZATION
1) DRYING NUMBER OF PRODUCTS.
2) BACTERIAL AND VIRAL CULTURE IS PRESERVED.
3) ANTIBIOTICS AND PLANT EXTRACTS.
4) FREEZE DRIED ROSES ARE USED IN WEDDING DECORATIONS.
5) TO STORE WATER DAMAGED MATERIALS SUCH AS RARE AND
VALUABLE MANUSCRIPTS.