In the ocean many organisms produce light. There are also many diffent colors. In this practical we will isolate these bacteria from fresh fish.


  • 1 Fresh fish, make sure it is really fresh from the sea. Ask for it at a fish shop.
  • 4 Artificial Seawater plates, simply add 10% agar before autoclaving
  • 100 mL Artificial Seawater
  • 2 50 mL Erlenmeyer flasks
  • Glass spatula
  • Inoculation loop
  • 100 mL beaker glass with some 95% ethanol
  • Gas burner
  • Air pump, tube and diffuser


  1. Sterilize a inoculation loop in a flame
  2. When it is cooled down, scrape the loop along the skin of the fish
  3. Streak the loop onto the plate
  4. Repeat this procedure onto a second plate
  5. Incubate one plate at RT(24° C) and one in the fridge (8° C)
  6. Take a look at your plates in total darkness after 2 days or more
  7. As soon as you can observe colonies, restreak these on fresh plates
  8. As soon as all colonies look the same, you may assume you have a pure culture
  9. Sub culture a colony in a 25 mL ASW liquid medium in a Erlenmeyer flask. Incubate at 24° C.
  10. Put the tube with diffuser in the flask and turn on the air pump

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