BioMatsuri 2021

# Cultivating Bacteria

GOALS

  • Learn how to make plates
  • Learn how to swab bacteria
  • Learn how to use Parafilm
  • Learn about different growth media

# Kit Content

  • Petri Dishes
  • Inoculation Loops
  • Agar 2g
  • Sugar 3g
  • Chicken Stock 2g
  • Parafilm
  • Water Bottle
  • Zip loc bags

# Preparation

Please prepare the following:

COLLECT SOIL & LEAVES

Collect different kinds of soils.

  • From a river
  • From a pond
  • From a park or garden

Use the zip-loc bags to collect different kinds of soils. Also use one bag to collect dry leaves. Please collect enough soil so that we can fill the bottle during the workshop.

🍃 🍃 🍃

COLLECT WATER

  • Collect water from pond or river Use a 500ml PET bottle to collect water.

ONE COOKED EGG

  • Please prepare a cooked egg. Onsem tamago is also ok. 🥚

Please prepare the following 1 DAY BEFORE the workshop:

PREPARE PETRI DISHES

  • Mix the following ingredients: 150ml Water, 2mg Agar, Sugar Stick, 2mg Chicken Stock

  • Use a Cooking Pot and cook it for 2min. Stir well.

  • Take 5 Petri Dishes

  • Pour ca. 20ml into each Petri Dish, enough to cover the bottom of the dish.

  • Let the Agar in the Petri Dishes settle, it takes ca. 1 hour.

  • Once the agar is solid, turn then petri dishes around, so that the bottom of the dish is on top. This avoids condensation.

# Background

# Protocol: Plating Bacteria

The goal is to cultivate specific bacteria on top of the agar inside the petri dish. In previous on-site workshops we used natural color and glowing bacteria to paint pictures. Unfortunately it was not possible to send these bacteria - let's go bacteria hunting instead!

# How to plate

  • Don't keep the petri dish open too long. Dust and other bacteria will get inside.
  • Don't flip the lid of the dish.
  • Don't poke inside the agar. Gently drag the loop on top of the agar.

# Finding Bacteria

Where are interesting bacteria?

On your skin? Inside your nose or mouth? On your dog or cat? Toilet? Kitchen Sponge? On your phone or keyboard?

  1. Use the inoculation loop to get some bacteria. If it is too dry, use some drops of water to make it moist.
  2. Open the Petri Dish
  3. Gently spread across the Agar.
  4. Draw a picture - if you like.
  5. Close the Petri Dish with Parafilm.
  6. Write on the bottom the date, name and content.
  7. Incubate!

What are good places to incubate?

Different bacteria like different temperatures. Incubate your petri dishes at different places and find out the difference. Some need light, some don't.

Petri Dishes are usually used to grow pure cultures - that is only one type of bacteria.

# Protocol: Making a Winogradsky Column

Winogradsky columns are self-enclosed eco-systems that support of society of bacteria. By creating an aerobic/anaerobic gradient and sulfur gradient, a variety of ecological niches for a variety of bacteria are created.

  • Water Bottle
  • Soil
  • Pond Water
  • Egg
  • Leaves or paper
  1. Fill bottom of water bottle with ca. 1cm soil.
  2. Peel and thoroughly mash the egg, add to bottle.
  3. Cover with a layer of soil.
  4. Tear leaves or paper, add to bottle.
  5. Add more layers of different soil, until bottle is full.
  6. Fill remaining space with pond water.
  7. Close lid.
  8. Incubate in sunlight

It will take some days and weeks to establish the ecosystem.

Do not mix or shake the finished bottle.