degradation of bioplastic by micro organism seminar neha
TRANSCRIPT
PRESENTED BY:-
NEHA SAHOO 09-PE-12
DEGRADATION OF BIOPLASTIC BY MICRO ORGANISM
OVERVIEW INTRODUCTION HISTORY TYPES OF BIOPLASTIC MICRO-ORGANISMS DEGRADING BIOPLASTIC DEGRADATION OF BIOPLASTIC BIODEGRADATION OF PHA DEGRADATION OF PHA BY ENZYME BENEFITS , DRAWBACKS ,APPLICATIONS OF PHA RECENT TECHNOLOGY ADVANTAGES OF BIOPLASTIC CONCLUSION
INTRODUCTIONPLASTICS
Defined as polymers which on heating become mobile. Non metallic moldable compounds. Pure plastics have low toxicity. Plasticizers like adipates and phthalates are added to brittle plastics.
TYPES OF PLASTICS Thermoplastics Thermosetting
BIOPLASTIC Plastic made partially or wholly from polymers derived from biological
sources. Polymer are lipid in nature. Degraded by fungi, bacteria ,enzyme and also in open air. Size, number of granules, monomer composition etc vary depending on
producer organism.
History Early History:
Natural resin like amber was used during Roman times.
In 1800s:John Wesley Hyatt discovered celluloid. This was the
first widely used plastic.
In 1900s:Plastic made from synthetic polymer was used.
Cellulose came into existence.
In 2000s and beyond: Demand for plastic is continually
growing.
Now a days, bioplastic used are cellulose based, starch
based and used as” BIODEGRADABLE POLY BAG”
RenewableRenewableResource-basedResource-based
MicrobialMicrobialsynthesizedsynthesized
• Aliphatic polyesterAliphatic polyester
• Aliphatic-aromatic Aliphatic-aromatic polyesterspolyesters
• PolyesteramidesPolyesteramides
• Polyvinyl alcoholsPolyvinyl alcohols
• Polyhydroxy Polyhydroxy alkanoates (PHAs)alkanoates (PHAs)• Polyhydoxybutyrate Polyhydoxybutyrate
co-valerate (PHBV)co-valerate (PHBV)
• PLA PolymerPLA Polymer (From Corn)(From Corn)• Cellulosic plasticsCellulosic plastics• Soy-based plasticsSoy-based plastics• Starch plasticsStarch plastics
Petro-Bio Petro-Bio (Mixed) Sources(Mixed) Sources
• SoronaSorona
• BiobasedBiobased PolyurethanePolyurethane
• Biobased Biobased epoxyepoxy
• Blends etcBlends etc
BIOPOLYMERS: CLASSIFICATIONBIOPOLYMERS: CLASSIFICATION
Petro-basedPetro-basedsyntheticsynthetic
TYPES OF BIOPLASTICS
Starch based plastics
Cellulose based plastics
Aliphatic polyesters
Polyhydroxy butyrate(PHB)
Polyhydroxyhexanoate(PHH)
Polyhydroxyvalerate(PHV)
Polylactic acid(PLA)
Polyhydroxyalkanoates(PHA)
Polyamide 11(PA 11)
PLASTIC MICRO-ORGANISMSYNTHETHIC PLASTIC
1) Polyethylene Brevibacillus borstelensisRhodococcus rubber
2) Polyurethane Fusarium solaniCladosporium sp.
3) Polyvinyl chloride Aspergillus nigerOchrobactrum TD
4)BTA –copolyester Thermomonspora fusca
NATURAL PLASTIC1) Poly(3-hydroxybutyrate) Pseudomonas lemoignei
2) Polycaprolactone Clostridium botulinumFusarium solani
3) Polylactic acid Bacillus brevis
POLYMER BLENDS1) Starch/polyethylene Aspergillus niger2) Starch/polyester Streptomyces
The most important reaction for initiating the environmental degradation of synthetic polymers is the abiotic hydrolysis.
Bacteria and fungi degrade both natural and synthetic plastic..
Polymer first converted to monomer, then it is mineralized and the large polymer passes through the cellular membrane, so it is depolymerized to small monomer and then it is absorbed and biodegraded within microbial cell.
Degradation is called mineralization when end product is CO2,H2O and methane.
When O2 is available, microbial biomass ,CO2 ,methane and water is primary product.
Generally ,an increase in molecular weight decreases polymer degradation.
DEGRADATION OF BIOPLASTIC
BIODEGRADATION OF NATURAL PLASTIC
Widely produced microbial bioplastics are PHB, PHA and their derivatives.
STRUCTURE OF PHA:
PROPERTIES OF PHA: Natural polyester of bacteria. Substitute for petrochemical plastic. Molecular mass of PHA is between 2×105 to 3×106 Daltons. Analogous material properties to thermoplastics to elastomers
ranging from C3 to C14..
SOURCES
Anaerobic and aerobic micro-organism degrading
PHA isolated from ecosystem.
Soil:Pseudomonas lemoignei
Fresh water:Comamonas testosterone
Produced from plastids of transgenic plants like
Arabidopsis thaliana,Brassica napus.
Nicotiana tabacum,Medica sativa are plants
that produce PHA by transgenic method.
Carbon Cycle of Bioplastics
CO2
H2O Biodegradation
CarbohydratesPlastic
Products
Plants
Fermentation PHA Polymer
Photosynthesis
Recycle
DEGRADATION OF PHA BY ENZYME Microbial(enzymatic) action degrade PHA by secreting PHA
depolymerase
Two different PHA depolymerase exist:
Extracellular(e-PHA depolymerase)
Intracellular(i-PHA depolymerase)
i- PHA depolymerase are released when nutrients are supplied
back to medium and actively degrade stored native PHA.
e-PHA depolymerase are carboxyesterases ,and can hydrolyse
water soluble PHA to water soluble monomer. Enzyme compose of two domain:
substrate-binding domain catalytic domain and linker region which connect two
domain.
DEGRADATION OF PHA BY ENZYME(CONTD.)
The catalytic domain composed of triad(Ser-His-
Asp).Serine part of lipase box pentapeptide(Gly-X-Ser-X-
Gly) and found in hydrolases (lipases,esterases etc).
Most PHA depolymerase donot bind to anion exchanger
and have strong affinity for hydrophobic materials.
Best PHA degrading bacteria is P.lemoignei that
produces 7 different extracellular PHA –depolymerase.
Biodegradation by PHA Depolymerases
BENEFITS & DRAWBACKSBENEFITS
Synthesis process is eco-friendly.
Bio-degradable.
Transparency.
DRAWBACKSUnsatisfactory mechanical properties.
Brittleness.
Applications of PHA
Medical applications Development of cardiovascular products
Drug delivery
Cell implants
Packaging films, cosmetic products
Agricultural applications Plastic film for crop protection, Seed encapsulation
Mobile phone casings,CD etc
RECENT TECHNOLOGYEco-One
Organic additive that biodegrade plastic when disposed in
microbe rich environment.
Allows plastic to be consumed by microbes.
MECHANISM
Formation of BioFilm
Expansion of the Polymer Matrix
Initial Breakdown of Polymer Chain
Breakdown Continues
Final Stages of Breakdown
Advantages of Bioplastic
Take less time to break down.
Are renewable.
Good for environment.
Require less energy to produce.
Are easier to recycle.
Are not toxic.
Reduce dependence on foreign oil.
CONCLUSIONTo date, more than 160 different polyesters with plastic
properties have been described and this number is growing
exponentially by means of genetic and metabolic
engineering techniques.
It could be expected that many other bioplastics with
different structures, properties and applications could be
obtained if the appropriate organism were selected and
genetically manipulated.
In conclusion, because of their special characteristics and
broad biotechnological applications, bioplastics are
compounds with an extremely promising future.
REFERENCESBacon, C., and J. White. 2000. Microbial endophytes. Marcel Dekker,
NewYork,NY.
Cosgrove, L., P. L. McGeechan, G. D. Robson, and P. S. Handley.
2007.Fungal communities associated with degradation of polyester
polyurethanein soil. Appl. Environ. Microbiol. 73:5817–5824.
Crabbe, J. R., J. R. Campbell, L. Thompson, S. L. Walz, and W. W.
Schultz.1994. Biodegradation of a colloidal ester-based
polyurethane by soil fungi. Int. Biodeterior. Biodegrad. 33:103–113.
Darby, R. T., and A. T. Kaplan. 1968. Fungal susceptibility of
polyurethanes.Appl. Microbiol. 16:900–905.
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