Culture of bacteria

BY: PRATYUSH HARSH & SOURAV NAYAK

A

WEAPON TO ERADICATE

PLASTIC

• Plastics act as a foe and friend to environment. The project describes about a method to degrade plastics from our surrounding. We have used a very common bacteria, pseudomonas that helped in the process. The process is little slow but very effective.

Gist of the project

Cultural Characters of Pseudomonas

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 370C.

• Growth on ordinary media producing large opaque irregular colonies with distinctive musty mawkish or earthy smell.

Petri dish

Beaker

Conical Flask

Incubator

Autoclave

Laminar air flow

Beef extract

Peptone

Agar Powder

REFRIGERATOR

Inoculation loop

Step 1:-• Take 100ml of water in a beaker.• Add -Agar powder (1.3g per 100ml),

Peptone (4g per 100ml), Beef Extract (4g per 100ml)

Step 2:-• Maintain the ph of the mixture to be

7.5 with NaOH.• Cover the flask with a piece of cotton

plug and aluminium foil.

Step 3:-• Keep the medium and petriplates in the

autoclave with some water at constant Pressure of 15 lbs and temperature 121 0C for 20 minutes.

Step 4:-

• Take the conical flask and pour out the liquified medium in a sterile petri plate immediately to avoid solidification of medium.

Step 5:-

• 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 contamination.

Step 6:-

• If the Petri Dish is completely cooled then place it in the refrigerator for about 24 hours.

Step 7:-

• 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.

Step 8:-

• 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 bacterial solution.

• 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 the environment.

Thank you