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.

Thank You !Thank You !