2. 1869 Celluloid John Wesley Hyatt
1912
(1838 erstmals
erzeugt)
PVC (Polyvinylchlorid) Fritz Klatte
1920-28 Theorien über den Aufbau von
Kunststoffen (Nobelpreis 1953)
Hermann Staudinger
1930 Neopren DuPont / USA
1930 Polystyrol (Styropor) BASF, IG Farben
1931 Polyethylen ICI / UK
1935 Polyamid (Nylon) DuPont / USA
1937 Polyamid (Perlon) BASF, IG Farben
1937 Polyurethan BASF, IG Farben
1938 Polytetrafluorethylen (Teflon) DuPont / USA
1941 Polyethylenterephthalat (PET) Calico Printers / UK
1951 Polypropylen Philipps Petroleum /
USA
1953 Polycarbonat Bayer
3.
4. Importance
„ 2003- North America
„ 107 billion pounds of
synthetic plastics
produced from
petroleum
„ Take >50 years to
degrade
„ Improper disposal and
failure to recycle Æ
overflowing landfills
5.
6. „ Degradable polymers that are naturally degraded
by the action of microorganisms such as bacteria,
fungi and algae
„ What are Bioplastics?
„ Benefits Include:
„ 100 % biodegradable
„ Produced from natural, renewable resources
„ Able to be recycled, composted or burned without
producing toxic byproducts
7. Carbon Cycle of Bioplastics
CO2
H2O
Biodegradation
Carbohydrates
Plastic Products
Plants
Fermentation PHA Polymer
Photosynthesis
Recycle
8. Polyhydroxyalkanoates (PHAs)
„ Polyesters accumulated inside microbial
cells as carbon & energy source storage
Ojumu et al., 2004
Polyhydroxyalkanoates, or PHAs, are homo- or
heteropolyesters synthesized and intracellularly stored by
numerous prokaryotes.
9.
10. Polyhydroxyalkanoates (PHAs)
„ Produced under conditions of:
„ Low limiting nutrients (P, S, N, O)
„ Excess carbon
„ 2 different types:
„ Short-chain-length 3-5 Carbons
„ Medium-chain-length 6-14 Carbons
13. Polyhydroxybutyrate (PHB)
„ Example of short-chain-
length PHA
„ Produced in activated
sludge
„ Found in Alcaligenes
eutrophus
„ Accumulated
intracellularly as
granules (>80% cell dry
weight) Lee et al., 1996
15. phbC-A-B Operon in A. eutrophus
„ Structural genes encoded in single operon
„ PHA synthase
„ β-ketothiolase
„ NADPH-dependent acetoacetyl-CoA reductase
Lee et al 1996
Ralstonia eutropha (Alcaligenes
eutrophus)
23. PHA-Synthesis in Bakteri vs Transgenic Plants
Production PHA Purification
Of PHA
Production
of starch
Isolation
of starch
Hydrolysis Fermentation Purification of
PHA
90% 90% 90%
30%
90%
Plant
Trangenic
Plants
Bacteria
30. Recovery of PHAs from Cells
„ PHA producing microorganisms stained
with Sudan black or Nile blue
„ Cells separated out by centrifugation or
filtration
„ PHA is recovered using solvents
(chloroform) to break cell wall & extract
polymer
„ Purification of polymer
31. Bioplastic Properties
„ Some are stiff and brittle
„ Crystalline structure Æ rigidity
„ Some are rubbery and moldable
„ Properties may be manipulated by blending
polymers or genetic modifications
„ Degrades at 185°C
„ Moisture resistant, water insoluble, optically
pure, impermeable to oxygen
„ Must maintain stability during manufacture and
use but degrade rapidly when disposed of or
recycled
32. Biodegradation
„ Fastest in anaerobic sewage and slowest in
seawater
„ Depends on temperature, light, moisture,
exposed surface area, pH and microbial activity
„ Degrading microbes colonize polymer surface &
secrete PHA depolymerases
„ PHA Æ CO2 + H2O (aerobically)
„ PHA Æ CO2 + H2O + CH4 (anaerobically)
