PAPER PRESENTATION

CHOKING POLYETHYLENE TEREPHTHALATE USING SPHINGOMONAS PAUCIMOBILIS BY ADAPTING CALCIUM

ALGINATE ENTRAPMENT TECHNIQUE

ABSTRACT

Plastics is the name given to different type of polymers with high molecular

weight that are used for varied applications in day to day life and can be

degraded by various processes. Considering their abundance in environment

and the need for degradation, microbial process seems to be the most effective

one. This study deals with the degradation of Polyethylene Terephthalate using

Sphingomonas paucimobilis through immobilization technique. Polyethylene

terephthalate (sometimes written poly(ethylene terephthalate)), commonly

abbreviated PET, PETE, or the obsolete PETP or PET-P, is a thermoplastic

polymer resin of the polyester family and is used in synthetic fibers; beverage,

food and other liquid containers; thermoforming applications; and engineering

resins often in combination with glass fiber.

The accumulation of this plastic causes threat to the environment. S.paucimobilis is a gram negative, aerobic, rod shaped bacterium that can be easily isolated from contaminated soil or water and can be grown in thioglycollate and brain-heart infusion broths and in blood culture systems. The degradation of PET is entertained by using Spingomonas paucimobilisbiomass. The bacterial biomass was immobilized on the microporous hollow fibres using calcium alginate entrapement technique.The experimental result show that the PET ‘s rate of degradation is higher and efficient.

POLYETHYLENE TEREPHTHALATE

PET was discovered and patented in England in 1941.

Polyethylene terephthalate is a thermoplastic polymer resin of the

polyester family.

Polyethylene terephthalate may exist both as an amorphous

(transparent) and as a semi-crystalline polymer which might appear

transparent or opaque and white depending upon the crystal

structure and particle size.

.

Two monomers viz Ethylene glycol and Terephthalic acid on esterification synthesize a monomer ,bis -β-hydroxyterephthalate which on polymerization (polycondensation) produce PET with water as the byproduct

STRUCTURE OF PET

THE PLASTIC EATER

Sphingomonas paucimobilis is a non sporing, non fermentative,

aerobic Gram-negative soil bacillus that has a single

polar flagellum with slow motility.

It exists in environmental niches such as water, including hospital

waste systems. Not part of human flora. Mode of transmission is

uncertain, probably involves patient exposure to contaminated medical

devices or equipments.

Due to their biodegradative and biosynthetic capabilities,

sphingomonads have been utilized for bioremediation of environment

for its ability to degrade aromatic compounds.

ISOLATION AND CULTIVATION :

Sphingomonas paucimobilis isolated from contaminated soil or

water is grown in thyoglycollate and brain and heart infusion broths

and in broths used in blood culture systems.

INCUBATION CONDITIONS AND DURATION:

Within 24 hours of inoculation these organisms produce

detectable growth on media incubated at 35°C in carbon dioxide or

in ambient air.

COLONIAL APPEARANCE:

After the incubation colonies of sphingomonas appear as

yellow spots due to its yellow pigment production.

CALCIUM ALGINATE CELL IMMOBILIZATION

Calcium alginate cell immobilization is employed in entrapment of

microbial cells like Bacteria ,Yeast ,etc

PREPARATION OF ALGINATE SOLUTION:

Dissolve 20g of sodium alginate in 500ml of

deionised water at 100 C for 30 min and mixed with 500 ml of sterile ⁰water and cooled at room temperature(22± 1 C)⁰

PROTOCOLCells were cultured in 750 ml of nutrient broth at 30 º C and harvested at the middle of the exponential phase by high speed centrifugation

↓

The cell pellet was washed with 200mM Phosphate buffer and

resuspended in 20ml of 0.1 % peptone water

↓To achieve homogeneous suspension,cell suspension was introduced

into alginate solution

CELL ENTRAPMENT IN CALCIUM ALGINATE

Polyethylene microporous ,hollow fibre of 0.7 mm diameter were dipped

in 2% Calcium chloride solution was drained onto a paper towel

↓

An alginate -cell film was formed of dipping the fibre into the sodium

alginate cell suspension for 3 min ,thus resulting a thin film around the

fibre surface

↓

The gelatin fim was formed by dipping the fibre in 2% Calcium chloride

solution and allowing the fibre to stay in solution for 30 min to form a

firm gel ,thus resulting gel with the thickness of 300-400 micrometer

↓

The fibre biocatalyst was activated by incubating it at 30º C overnight

to allow most of the cell to grow and occupy the entire gel pore

volume

↓

The PET fibre with the immobilized cells were placed in a glass column

which was connected to a reservoir with tubing through a peristaltic

pump to allow circulation of PET, repeated circulation results in

effective degradation

ADVANTAGE OF APADTING IMMOBILIZATION TECHINQUE

Immobilized cells grow better than free cells even under

environmental stress

Economic advantage over traditional method by saving more time

Effective degradation compared to free cells.

12

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Kingsoft Officepublished by www.Kingsoftstore.com

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PAPER PRESENTATION

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