Lab Book

20/06/16

After the interlab study, we made streak plates from the colonies we had grown. We regrew all the samples on LB agar with 1 in 1000 dilution of Chloramphenicol. We did this to isolate a pure strain of the transformed interlab E. coli, therefore allowing us to grow up a new, genetically-identical plate. Our lab supervisor, Matthew Peake, showed us the correct streaking technique as the Computer Science students had not learnt this technique before.

22/06/16

After analysing the trial interlab results, we decided to re-plate up the positive control to ensure that we would have enough colonies to carry out the interlab study again.

28/06/16

Today we made a microbial fuel cell by following the Reading University’s protocol, see below.

We sourced the material such as the neoprene gaskets, carbon fibre electrode material, cation-exchange membrane, J-cloth from Professor Ian Head, Dr. Ed Milner and Paniz Izadi from the School of Civil Engineering and Geosciences. We also sourced electric wires with crocodile clips and a multimeter from the Engineering Departments.

First, we prepared the 1M glucose solution, 0.02M potassium hexacyanoferrate (III) solution, 10mM methylene blue solution, these were made up in a 0.1M potassium phosphate buffer.

Phosphate Buffer

To start we made a stock solution of the two constituents compounds and then we diluted them down.

1M Potassium Hydrogen Phosphate Stock Solution

We dissolved 87.09g of potassium hydrogen phosphate (K2HPO4) in 400ml of distilled water. Once dissolved, this was made up to 500ml with distilled water.

1M Potassium Dihydrogen Phosphate Stock Solution

For the stock solution we dissolved 68.05g of potassium dihydrogen phosphate (KH2PO4) in 400ml of distilled water. This was again, once dissolved, made up to 500ml with distilled water.

0.01M Potassium Phosphate Buffer, pH7.0

For the final potassium phosphate buffer, we mixed 61.5ml of the 1M K2HPO4 stock solution with 38.5ml of the 1M KH2PO4 stock solution. We then added 900ml of distilled water to make up to 1 litre. This buffer was then used to make up the rest of the solutions required for the fuel cell, see below.

10mM of Methylene Blue

For the methylene blue, we dissolved 1.87g in 500ml of the potassium phosphate buffer.