Isolation of luminescent Bacteria from Squid

My first project in the lab was isolation of luminescent bacteria from squid, I’m going to share my experiment and observation. But before doing the experiment I had a question that “what is Bioluminescent Bacteria?” I found out they are the bacteria that produce light and they are found in seawater, in marine animal’s guts and on the surface of decomposing fish, and in the specialized organs of squid fish that provide bioluminescent bacteria as a safe place to live and a source of food.

In order to isolate the bacteria from squid I used two different sources. The first method required a 3.0% NaCl solution, by mixing 30 gr NaCl into 1 Liter distilled water. Then I placed the squid in a container and add enough 3.0% NaCl solution to the container to almost cover the squid. i then place the container in a refrigerator 16 degrees C for 24 hours. After 24 hours I checked the squid for luminescent bacteria by gently agitating the water in a dark room.

The second method was the dissect the squid and collect the ink directly from the squid. I needed to collect the ink from behind the eyes and from the sack in the body. First I cut the gut without cutting the ink sack inside the body, and separate the sack carefully from the body and collected the ink on the palate. Then I cut the tentacles away from the eyes and harvest the ink from behind the eyes. Then after collecting all the ink just added enough 3.0% NaCl solution to a container and incubated it at 18-20 degrees C.

Here is the link that shows clearly how to harvest the squid ink: