biodegradation of nylon 6 by NCIM psudonomas aerigosa

1. A Review on:
Studies on Bio-degradation of synthetic polymer Nylon 6 by Pseudomonas aeruginosa NCIM

2. Introduction
 From last three decades uncontrolled use of the plastics for
packaging (e.g. fast food), transportation, industry and agriculture
in rural as well as urban areas, has elevated serious issue of plastic
waste disposal and its pollution.
 Light-weight, inertness, durability, strongness and low cost are the
main advantages of plastic while it has disadvantages such as, it is
recalcitrant to biodegradation and difficult to degrade naturally.
 The global use of plastic is growing at a rate of 12% per year and
around 0.15 billion tones of synthetic polymers are produced
worldwide every year.
 Accumulation rate of plastic waste in the environment is 25
million tons/year

3. Use of plastics

4. Plastic’s adverse effects on our environment
1}Plastic pollute beaches &oceans
 Since the 1940s, plastic use has increased dramatically, resulting
in a huge quantity of nearly indestructible, lightweight material
floating in the oceans and eventually deposited on
beaches worldwide
2} Plastic bags litter the landscape
Once they are used, most plastic bags go into landfill, or rubbish
tips. Each year more and more plastic bags are ending up littering
the environment. if they are burned, they infuse the air with toxic
fumes.
3} Plastic bags kill animals
 About 100,000 animals such as dolphins, turtles whales,
penguins are killed every year due to plastic bags. Many animals
ingest plastic bags, mistaking them for food, and therefore die.
4}Plastic’s effect on human life
 Some of the constituents of plastic such as benzene are known
to cause cancer. Plastic resins themselves are flammable and
have contributed considerably to several accidents worldwide.

5. Methods for available for degradation
 Any physical or chemical change in polymer are due to environmental factors such
as light, heat, moisture, chemical conditions and biological activity is termed as
degradation of plastic.
Degradation of plastic
1. 2. 3.(Bio-degradation)
PROCESS A.Burying plastics samples in
soil or placin g it in a lake or
river
Burying plastic sample in
acompost or sea water
placed in a controlled
condition(pH,humidity,Te-
mperature)
Defined media inoculated with
mixed microbial population
(e.g. from waste water) or
individual microbial strains or
enzymes which may have been
especially screened for a
particular polymer
Advantages Most easy&Widely used Practically most suitable
Better analytical tools
available than would be
used for field test.
1.Faster rate of degradation
than natural condition
2.Preferred for many
systematic many investigation.
Disadv. A)Environment conditions can
not be well controlled.
B)Analytical oppurtunities to
monitor the degradation
process are limited
Lacks reproducibility due
to variable microbial
population
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6. Bio-degradation of Nylon -6
 Nylon 6 is a polymer obtained by ring – opening polymerization of ε caprolactam
Formation of Nylon 6 from ε caprolactam
 Due to its strong intermolecular cohesive force caused by hydrogen bonds
between molecular chains of nylon, the rate of degradation is less compared to
polyesters.
 Biodegradation of polymers is seen as one of the solution for current plastic
waste management problems.
 Nylon 6 monomer is metabolized by numerous microorganisms, including the
bacterial general pseudomonas aeruginosa , Trametes versicolor and many
other
N2

7. Objective
To Measure the thickness of nylon sheet
To Reduce the thickness of nylon sheet
To Measure adequate method for degradation of polymer
To Increase flexibility and elasticity

8. Methodology….
Step 1. Materials
 Commercial grade Nylon 6 was provided by Sigma Aldrich(American
multinational company). The material is in the form of pellet. All chemicals
and solvents used in all experiment were AR grade. A thin sheet of nylon 6
was prepared from nylon 6 pellets by melting and pressing the pellets of
Nylon 6.
Step 2. Selection of Microorganism
 The bacterium selected in the study was a Pseudomonas aeruginosa NCIM
2242, Trametes versicolor NCIM 1086 that is well known for its
biodegradation activity. The bacterial strain of above bacteria was obtained
from the National Collection of Industrial Microorganisms (NCIM) NCL, pune,
Maharashtra, India.
Pseudomonas aeruginosa NCIM 2242 Trametes versicolor NCIM 1086

9. Methodology….
Step 3: Sterilization of the sample
The nylon sheets were dipped in absolute alcohol for a few hours.
 Washed with distilled water and later dried.
 No physical or chemical changes were observed in the sample sterilization
treatment.
Step 4: Submerged cultivation procedure
 A nylon sheet was exposed to submerged cultivation process Microbial
degradation was performed in Erlenmeyer flasks in shaker condition.
 Flask containing small sheet of nylon 6 and 100 ml of the liquid glucose –
salt medium at a pH 6.25. The medium contained per liter of deionised water,
10 gm of glucose, 1 g KH2PO4, 0.5 gm of MgSO4 7H2O and 0.5 gm of (NH4)2
SO4 and 0.1 gm of CaCl2.

10.  Aliquots (100 ml) of medium were poured into 500 ml Erlenmeyer flask and
sterilized in an autoclave for 20 min at 121 oC and 1.2 atm, after cooling the medium
was inoculated with 5 ml of the fungi spore suspension obtained by suspending
spores from one agar slant tube in 20 ml sterile water. The fermentation broth was
incubated on a rotary shaker at 30 oC and 90 rpm. Nylon 6 was the sole source of
nitrogen in the medium. Degradation was left to proceed for a period up to 90 days.

11. Results &discussion ….
 Degradation of Nylon 6 sheets in submerged cultivation using Trametes
versicolor NCIM 1086 and psedonomas aerigunossa was carried out for 15,
30, 45, 60 ,75 and 90 days. Parallel to samples inoculated with the fungus
(biotic sample) blank experiment was carried out with Nylon 6 sheets placed
equally composed media without the fungus (a biotic sample).
1)Morphological Study:
 Degradation of sheets of Nylon 6 was observed my measuring thickness of
sheets and weight reduction of sheets as it is treated with selected fungi. The
color of sheets becomes brownish and surface morphology become rough
when sheets are exposed to fungi.

12. Day Control
condition
Trametes
versicolor
condition
Pseudomonas
aeruginosa
condition
0 day 0.013 0.013 0.013
15 day 0.013 0.012 0.011
30 day 0.012 0.012 0.009
45 day 0.01 0.011 0.008
60 day 0.009 0.008 0.008
75 day 0.008 0.007 0.006
2)Decrease in weight
Table 1. decrease in weight of nylon(gm) sheet under different condition

13.  The amount of degradation was determined by studying weight loss of
sheets. Weight of sample nylon sheets maximum reduced from 0.013 gm
to 0.006 gm in under the Pseudomonas aeruginosa compare to the
another condition.

14. Table 2. decrease in Thickness (mm) of nylon sheet under different
condition
Day Control
condition
Trametes
versicolor
condition
pseudomonas
aeruginosa
condition
0 day 0.117 0.117 0.117
15 day 0.116 0.111 0.111
30 day 0.114 0.099 0.094
45 day 0.114 0.092 0.089
60 day 0.107 0.081 0.075
75 day 0.105 0.074 0.035
4)Decrease in Thickness

15.  The amount of degradation was determined by studying weight loss of
sheets. thickness of sample nylon sheets maximum reduced from 0.017mm
to 0.035 mm in under the Pseudomonas aeruginosa compare to the
another condition

16. 4)FTIR Study
A FTIR Spectra of Nylon 6 Untreated

17. FTIR Spectra of Nylon 6 pseudomonas aeruginosa NCIM 1086
 The functional groups of Nylon 6 mediated with selected bacteria
Pseudomonas aeruginosa NCIM 2242 was determined by using FT-IR
spectroscopy (at Room Temp.) The strength of characteristic bands of C (O) NH
occurring around 3300, 1640, 1550 and 1018 cm-1 decreased after six months.
Formation of new groups like CH3, CONH2, CHO and COOH, may be formed
due to hydrolysis and oxidation

18. FTIR Spectra of Nylon 6 Trametes versicolor NCIM 1086 treated 90 days
samples (the strength of Characteristic bands of C (O) NH occurring around
3300, 1640 and 1550 cm-1 decreased after 90 days)Also shows formation of
new groups as CH3(2022), CHO(2700)).

19. Conclusion
 Fungus Trametes versicolor NCIM 1086, Pseudomonas aeruginosa NCIM
2242 mediated biodegradation of nylon 6. FTIR spectra for the polymer
nylon 6 indicate formation of new groups such as CH3, CHO and COOH.
This group may be formed due to process of hydrolysis and oxidation. This
may be caused due to cleavage of C-C bond in CH2-CH2 adjacent to
Nitrogen atom. Also the C=N stretching get weaker here. Degradation of
polymer was also confirmed by weight loss of nylon sheets and decrease in
thickness of nylon sheet. Therefore, the data indicates the maximum
potential for degrading recalcitrant polymer such as nylon 6 by
Pseudomonas aeruginosa aeruginosa NCIM 2242.

20. References
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