J/13 July 2012

From 2012.igem.org


July
MTWTFSS
            1
2 3 4 5 6 7 8
9 10 11 12 13 14 15
16 17 18 19 20 21 22
23 24 25 26 27 28 29
30 31


Day Thirteen

(10:00 am) The polystyrene test dish is ready and has solidified so it can be plated up when there is some bacteria to see if it works as a medium.

(12:00 pm) On further analysis the original plan of a agar and layer of polystyrene covering it has proved ineffective as the polystyrene just formed a thick solid in the centre. However, the team had another idea yesterday. The idea is to attempt to crush the Polystyrene 'sugar' (unexpanded polystyrene beads) using either a pestle and mortar or crushing them with toughened glass beads. Then the crushed 'sugar' can be suspended in minimal medium, thus creating cloudy media, where hopefully halos around specific colonies will form when polystyrene degrading bacteria are present. Its important to only use a low concentration of the the crushed 'sugar' as too much will mean that the halos won't form due to the slow degradation by these bacteria.

(15:00 pm) The grinding of polystyrene begins, but the process is very slow. The pestle and mortar was producing minimal results so the team switched to the grinder machine mixing our 'sugar' with glass beads to, by sheer force, crush the polystyrene down to an even finer grain.

(4:45) The grinding machine couldn't grind the polystyrene 'sugar' down, so the group has been seeing whether just adding the 'sugar' into agar may work on its own. Through experimenting with varying amounts of 'sugar' to agar (2.5% and 5% polystyrene), and varying the amount of agar used, the amount decided on is between 10 and 15 grams of agar/'sugar' mix at 5% 'sugar'. 20g of agar/'sugar' mix was just too deep as the 'sugar' just settled at the bottom or sides. At 10g agar/'sugar' mix, the 'sugar' is just below the agar's surface making it easier for bacterial colonies to access the polystyrene as a carbon source.