Team:Groningen/Template/MODULE/project/MBD/experiments

The hydrogel in the bandage should have nutrient source for the bacteria to grow. Using rich media like M17 in the bandage for growing Lactococcus lactis is not a good idea. Rich media might support the growth of other bacteria’s present on the wound which might cause adverse problems. To avoid this kind of complications we decided to use chemically defined media. Chemically defined media is a buffered media containing all the aminoacid, vitamins and other metal suppliments.

1. Glucose Concentration optimization for Nisin production

To increase the lifetime of the bandage we decided to increase the amount of carbon source. Lactococcus lactis is lactic acid producing bacteria, increasing the amount of carbon source in the media results in faster production of lactic acid. Lactic acid present in the media represses the growth of bacteria. The presence of phosphate buffer in the chemically defined media solves this problem to some extent. It has been reported that Nisin is produced only in exponential growth phase. In order to evaluate the glucose concentration at which Nisin production is higher we grew Nisin producing strain in CDM media and every two hours sample was collected to perform Nisin activity test.

Based on the nisin activity assay we got similar diameter of halo for 20 g/l and 40 g/l of glucose concentration. We analyzed the supernatants using HPLC to find the exact concentrations of nisin. HPLC analysis showed that at 20 g/l of glucose concentration we get higher nisin yield.