1. Procedure of PLA-Production and Degradation

2. 2. Separation of Cells by Centrifugation
2.1 Fill 40 ml of fermenter medium in two 50 mL Falcon Tubes.
2.2 Centrifuge the Falcon-Tubes at 5000 rpm for 10 minutes.
Supernatant
Pellet

3. 3. Concentration of Lactic acid by destillation
mL of supernatant will be destilled.
Heating system
Distillation flask with supernatant
Reflux condenser
Flask with distilled water
Water suply
Thermometer

4. 3. Distillation
3.2 Distill app. 50 mL H2O.
3.3 Cool down the lactic acid solution.

5. 4. Polymerization of Lactate
4.1 The following lab items you need for the polymerization:
Test tube rack
Funnel
Petri dish
Test glass holder
Test glass
SnCL2
Burner
Lighter
Probe
Protection googles
Spatula

6. 4.2 Pipette 5 mL of lactate-solution in a test glass.
4.3 Add the catalyzer SnCl2.

7. 4.4 Heat the solution for 5 – 10 minutes in a fume cupboard by steady shaking to avoid boiling retardation.

8. 4.5 When an intensive white smoke is coming up poor the liquid in a 40 mL beaker.
 By cooling down in the beaker PLA gets solid.

9. 5. PLA-Degradation by Hydrolyses
5.1 Add 10 mL dist. water into the beaker and stirr.
 PLA gets slowly soluble.
10 mL H2Odist.

10. 6. PLA-Degradation
PLA-Foil
PE-Foil
7 d d d d
Source:
BASF