GROWTH CONDITIONS AND EXPERIMENTAL SETUP FOR BACTERIAL GROWTH AND THE FADING OF PHENOLPHTHALEIN IN ALKALINE SOLUTION

• Main Author: Backlöf, Kalle
• Format: Others
• Language: English
• Published: Högskolan i Skövde, Institutionen för vård och natur 2011
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-5473

The whole project consisted of two different parts. The first subproject were running optical density measurements to assist in finding optimal growth conditions and experimental setup for use of E.coli BL21 (DE3) bacteria with the PYCARD gene transformed into them. The transformed bacteria will be used for generating data for modeling. Previous laboratory attempts had problems with timing of the exponential phase when several tests were performed simultaneously. The optimizations of a method for displaying growth include trying out using different medium but also different inoculation ratios between culture and medium to see the effects on growth rate. Results have shown that lysogeny broth together with an inoculation ratio of 1:25 results in rapid absorbance increase in the bacterial growth curves.The second part of the thesis project was to study the kinetics of fading of phenolphthalein in sodium hydroxide solution in order to provide a basis for experiments illustrating this in laboratory environment. Phenolphthalein is used in many different applications such as an active ingredient in some laxatives but the perhaps most common use is as an acid-base indicator of pH. The experiments were performed by mixing alkaline solutions of varying sodium hydroxide concentration together with sodium chloride, then after addition of phenolphthalein to study absorbance variations over time to illustrate the rate law which correlates the rate of color fade to sodium hydroxide concentration. The results have proven that they correspond directly so that increasing the concentration of sodium hydroxide raised the color fading rate just as much in percent.