Degradation of Bioplastic by Micro Organism Seminar Neha
Short Description
Download Degradation of Bioplastic by Micro Organism Seminar Neha...
Description
DEGRADATION OF BIOPLASTIC BY MICRO ORGANISM
PRESENTED BY:-
NEHA SAHOO
09-PE-12
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
INTRODUCTION PLASTICS
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”
BIOPOLYMERS: CLASSIFICATION
Renewable Resource-based
Petro-Bio (Mixed) Sources Petro-based synthetic
Microbial synthesized
•
•
•
•
•
PLA Polymer (From Corn) Cellulosic plastics Soy-based plastics Starch plastics
•
•
Polyhydroxy alkanoates (PHAs) Polyhydoxybutyrate co-valerate (PHBV)
•
•
Sorona
Aliphatic polyester Aliphatic-aromatic polyesters
•
Polyesteramides
•
Polyvinyl alcohols
•
•
•
Biobased Polyurethane Biobased epoxy Blends etc
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-ORGANISM
SYNTHETHIC PLASTIC Brevibacillus borstelensis
1) Polyethylene
Rhodococcus rubber Fusarium solani
2) Polyurethane
Cladosporium sp. Aspergillus niger
3) Polyvinyl chloride
Ochrobactrum TD Thermomonspora fusca
4)BTA –copolyester
NATURAL PLASTIC 1) Poly(3-hydroxybutyrate)
Pseudomonas lemoignei Clostridium botulinum
2) Polycaprolactone
Fusarium solani Bacillus brevis
3) Polylactic acid
POLYMER BLENDS 1) Starch/polyethylene 2) Starch/polyester
Aspergillus niger Streptomyces
DEGRADATION OF BIOPLASTIC
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.
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 Photosynthesis
H2O
Biodegradation
Recycle
Plants
Carbohydrates
Fermentation
Plastic Products
PHA Polymer
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-HisAsp).Serine part of lipase box pentapeptide(Gly-X-SerX-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 & DRAWBACKS BENEFITS Synthesis
process is eco-friendly.
Bio-degradable. Transparency.
DRAWBACKS Unsatisfactory Brittleness.
mechanical properties.
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 TECHNOLOGY Eco-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.
CONCLUSION To 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.
REFERENCES Bacon, 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 !
View more...
Comments
