Team:Valencia/Project/Lab work



1.- Construction of a Liquid Culture Calorimeter (LCC).

Method Building your own calorimeter system is easy. You just need to follow the next steps:

Characterization results After trying different combinations of shaking speed, flask tilt and culture volume, we obtained a combination of conditions suitable for the experiment (allowing optimal respiration of yeast culture): 270 rpm, approximately 10 º tilt and 100 ml in a 1L flask, with the thermocouple measuring submerged in the liquid.

In these conditions, the 4 LCCs were characterized with water at the temperature of the future experiments, in order to establish the range of heat losses to the environment of the system. The results are shown in the following figures:



To show how room temperature can affect temperature inside the LCCs, we repeated the experiment producing a variation in room temperature. The result was:



Troubleshooting

We have encountered some adversities regarding Armaflex©. This material is sensitive to mechanical damage and especially to water. No matter how careful we were, we found the insulation capacity of our system had drastically decreased after a few weeks.

The solution to this problem appeared, as usual, when we were not looking for it. In order to provide more oxygen to the culture, we increased the shaking speed and the flask tilt in an experiment with water. Surprisingly, the periodic oscillations disappeared and the temperature not only did not fall so much, but slightly increased. We found we could regulate the temperature with these two factors; therefore, we adjusted them so as to obtain almost stable temperature with a high shaking speed suitable for culture growth.

Another condition we changed was the position of the thermocouple inside the flask. They had been always placed in the upper part, having no contact with the liquid because of contamination reasons. However, our engineer team members suggested it would be better for the thermocouples to be submerged in the liquid. After carrying out an experiment, we saw there was not significant difference between both positions and none of them resulted in contamination either. Since the data obtained is more exact with the thermocouple submerged, we decided to keep them that way.

Click below to watch our system working during one of our experiments!

  

 Objectives  << 1.LCC Construction  >>  2.Hot Yeast Experiments