Pratyush Harsh and Sourav Nayak 3
• It grows anaerobically if nitrate is available.
• Growth occurs at wide range of
temperatures 6-420C the optimum being
• Growth on ordinary media producing large
opaque irregular colonies with distinctive
musty mawkish or earthy smell.
• Take 100ml of water in a beaker.
• Add -Agar powder (1.3g per 100ml),
Peptone (4g per 100ml),
Beef Extract (4g per 100ml)
• Maintain the ph of the mixture to be
7.5 with NaOH.
• Cover the flask with a piece of cotton
plug and aluminium foil.
• Keep the medium and petriplates in the
autoclave with some water at constant
Pressure of 15 lbs and temperature
121 0C for 20 minutes.
• Take the conical flask and pour out the
liquified medium in a sterile petri plate
immediately to avoid solidification of
• Cover the medium plate with another
petri dish. Care should be taken that
excess medium should not be poured in
the plate which may cause the
• If the Petri Dish is completely cooled
then place it in the refrigerator for
about 24 hours.
• Take it out from refrigerator and allow it
to come to room temperature. Take the
bacteria from subculture and make
marks as shown in the picture with
Inoculation loop. Take care that the
inoculation loop is sterilized. The streaks
can be done 3 to 4 times regularly as
shown in figure. The complete process
should be done in a laminar air flow.
• On streaking the bacteria are added to
the culture. Now allow it to multiply in
the dish ,keep this plate in the
incubator to prevent the infections
from other species.
• We see a growth of the bacteria on the
plate after 2 to 3 days. Now carefully
collect the bacteria in a test tube add
water to it .Now we have a pure
• Prepare the soil sample ready along
with the plastics and add the bacteria
mixture directly to the soil or in a
polythene cover. Add some amount of
sodium acetate that would enhance the
process of degradation of plastics.
• Keep another soil sample with same
amount of plastics but without the
bacterium added to it. Observe the
mixtures after every week and record
the observations .The weight of the
plastics in both the soil samples are
collected. Observe it for about 3-4
weeks. We observe that the plastics in
the soil sample containing the bacteria
are degraded more than the other.
• This shows that the bacteria has the
ability to decompose plastics .This is
only a small example to show that the
process happens ,but on a large scale
the effect would be much beneficial to