Milk was a baaaad choice..

Last Friday we had to come in to check on the nutrient requirement experiments for our unknown bacteria.

This is what the starch agar plate looked like after we added the Gram's iodine. There is no halo around the growth which means that the experiment is negative for amylase production. There was no blue/black precipitate which would mean that there was starch present but it was negative for amylase production. Teresa and Lisa's half shows a positive result.

The skim milk agar plate showed a small halo around the growth which means it is positive for casein protease production. There could also have been an opaque white area which would mean there was casein present but it was negative for casein protease production.

The blue tributyrin plate showed a halo around the streak but it looks the opposite of the halo which would show a complete hydrolysis of triglycerides and a positive reaction for lipase production. Our unknown was negative. The other options could be that there could be a dark blue precipitate which would mean there was a partial hydrolysis of triglycerides and that it is positive for lipase production. Also the agar could be pale blue agar and no halo that would mean there was tributyrin present and it was negative for lipase production.