1. BIOPLASTICS
By:
Mugdha Nigam
ME Biotech

2. Bio-Plastics
 Bio-based Plastics
Major focus is on “origin of life” or where
did Carbon come from..
 Biodegradable Plastics
Focus is on “end of life or disposal”
Defined by EN13432 and ASTM D6400

3. What are Biodegradable
plastics?
 Biodegradable or Compostable plastics are those
that meet all the scientifically recognized
standards of biodegradability of plastics and
plastic products independent of their carbon
origin.
 According to ASDM D6400, biodegradability is measured on
Mineralization, Disintegration and Safety of the material.
- atleast 90% conversion to CO2, water and biomass via
microbial assimilation.
- should occur within a time period of 180 days or less.
- no impacts on plants.
- etc……

4. Drivers for Bioplastics
 Reduced environmental impact.
 Disposal issues – Landfills.
 Concerns about human health.
 Legislative initiatives.

5. Lifecycle of Bioplastics

6. Types of Bioplastics (Kaeb, 2009)

7. Starch and Starch blends
 Virgin starch is brittle and difficult to be
processed. This problem is mainly caused by
the presence of strong inter‐ and intra‐
molecular hydrogen bonds between the
starch macromolecules.
 Thermoplasticized starch
 Cross-linked starch
 Starch esters
 Starch – Biopolymer blends

9.  High density
 Low resistance to oil and solvents
 Easy to process bur vulnerable to
degradation.
 Sensitive to moisture
 High water vapour permeability

10. Cellulose based Bioplastics
 Cellulose-based bioplastics are typically chemically-
modified plant cellulose materials such as cellulose acetate
(CA).
 Common cellulose sources include wood pulp, hemp and
cotton.
 These biodegradable plastics can be processed on
conventional injection molding machines or on extruders
adapted to their specific processing properties.
 The thermal resistance is somewhat lower, but the
permeability to steam and oxygen is relatively high
compared to that of standard plastics. The material is
resistant to oils and fats and, for a short while, even to weak
acids and alkalies.

11. Polylactic Acid (PLA)
 PLA is an aliphatic
polyester.
 The conformational ratio
of L- and D- lactic acid in
the polyester decides
the material properties.
 Degrades within 4 to 6
weeks .
 High stability
 Transparency

13. The biology of
Polyhydroxyalkanaotes (PHA)
 The carbon sources are assimilated, converted into
hydroxyalkanoate (HA) compounds and finally polymerized into
high molecular weight PHAs and stored as water insoluble
granules in the cell cytoplasm.
 PHAs are an excellent storage compound because their
presence in the cytoplasm, even in large quantities does not
disturb the osmotic pressure of the cell.
 These granules may be surrounded by a phospholipid
monolayer that contains specific granule associated proteins.
 PHA granules are intriguingly maintained in an amorphous state
in vivo.

14. A) Transmission Electron micrograph of Ralstonia eutropha H16 containing 70
wt% P(3HB) granules cultured in mineral medium containing palm kernel oil as
the sole carbon source for 48h.
B) Nile Blue stained R. eutropha cells containing P(3HB) granules cultivated for
72h in mineral medium containing palm kernel oil as the sole carbon source.

15. Chemical Composition of
PHAs
 approximately 150 different constituents of
PHAs have been identified as homopolymers
or as copolymers.

16.  Good thermoplastic material.
 Wide temperature range
 Lower crystallinity
 Tendency of shrinkage
 UV resistance

17. • Short chain-length PHAs (SCL-PHA):
contains 3-5 carbon atoms.
Monomer size
• Medium chain-length PHAs (MCL-
PHA): contains 6-14 carbon atoms
• Homopolymer: The polymerization begins with the
linkage of a small molecule or monomer through ester
Number of different bonds to the carboxylic group of the next monomer. A
homopolymer is produced when single monomeric units
are linked together. i.e P(3HB).
monomers in PHAs • Heteropolymer: When two or more different monomeric
units are linked together, a copolymer is formed. i.e
P(3HB-co-4HB).
• Natural PHAs: produced naturally by
microorganisms from general substrates. i.e Poly(3-
hydroxybutyrate) P(3HB)
Biosynthetic origin • Semisynthetic PHAs: requires addition of unusual
precursors such as 3-mercaptopropionic acid to
promote the biosynthesis of poly(3-hydroxybutyrate-
co-3-mercaptopropionic) [P(3HB-co-3MP)]

18. Wild type and recombinant strains used for pilot and large scale production of PHA

19. Strain and Process Development for industrial production of PHA

20. Commercially important
PHAs
 Poly(3-hydroxybutyrate)
[P(3HB)]
 Poly(3-hydroxybutyrate-
co-3-hydroxyvalerate)
[P(3HB-co-3HV)]
 Poly(3-hydroxybutyrate-
co-4-hydroxybutyrate)
[P(3HB-co-4HB)]
 Poly(3-hydroxybutyrate-
co-3-hydroxyhexanoate)
[P(3HB-co-3HHx)]

21. Comparison of mechanical properties of different PHAs with common plastics

22. In general
 SCL PHAs are highly crystalline and have poor
tensile strength.
 MCL PHAs are amorphous and very
elastomeric.
 P(3HB-co-3HHx) is an interesting copolymer.
 3HHx units addition(5 mol%) into the 3HB
sequence reduces the melting point from 180 °C to
less than 155 °C, thus significantly improving the
thermal processability and physical properties.
 Aeromonas caviae and A. hydrophila are the only
found organisms to naturally produce this polymer.

23. Applications of PHA in various fields
All materials for short life packing like
Packaging Industry
food utensils, films, electronic
appliances
Printing and Photography PHA are polyesters that can be easily
stained.
Chemical Industry
Heat sensitive matrices, latex gels.
Nonwoven matrices to remove facial
oil.
Textile Industry
PHA can processed into fibers.
Medical Implants
Medical implant materials, drug
controlled release matrices.
Healthy food additives PHA oligomers used as food
supplements to obtain ketone bodies.
Biofuels & additives
Hydrolysed to form combustible HA
methyl esters.
Protein Purification &
PhaP used to purify recombinant
Specific Drug delivery
proteins and along with specific
ligands, can achieve targeting to
dieseased tissue.

24. Advantages
 Lower fossil fuels consumption.
 Less dependency on non-renewable
resources.
 Lower CO and other green house gas
2
emissions in the atmosphere.
 Decrease in waste generation.
 Water saving.

25. Disadvantages
 Bio-based plastics are made from plant
sources like corn and maize. With already
increasing demand of food supply, Plastic
production from plants could create a steep
cut-short.
 Some bioplastics don’t readily decompose.
They require high temperature in especially
built pilot plants. Thus, they may not be so
economical.
 GMOs are used to increase productivity of
PHA and PLA.

26. Future developments prospects
 High cell density within short period of time.
 Controllable lysis of cells containing PHA
granules.
 Controllable PHA molecular weight.
 Use of PHA monomers as biofuels
additives.
 PHA blending with starch, cellulose.
 PHA as building blocks for new polymers.

27. References
 Lei Pei et al, Biotechnology of
Biopolymers, 2010.
 Guo-Qiang Chen, Chemical Society
Reviews, 2009.
 Ching-Yee Loo and Kumar
Sudesh, Malayasian Polymer Journal, 2007.
 Erwin T.H. Vink et al, Polymer degradation and
stability, 2002.
 Franziska Hempel et al, Microbial Cell
Factories, 2011.
 bioplastics MAGAZINE
www.bioplasticsmagazine.com/