Biotechnology (microbial fuel cells) Essay Example | Topics and Well Written Essays - 3000 words

Biotechnology (microbial fuel cells) - Essay Example 16.298 g of this component was added to 5.395 g of sodium phosphate monobasic monohydrate whose molecular weight was137.99 g/mol. Ammonium ferrous sulphate (for the COD test) was also prepared as was done in the first three experiments. The final concentration of this reagent was 0.025 M, whereas the final volume was 2 litres. The prepared solution was kept in the refrigerator ready for use. Synthetic wastewater, LB broth, and sucrose solution were covered with aluminium foil and tape indicator. Prior to autoclaving the solutions, the caps of the containers were loosened to improve the efficacy of the process. Microbial (Shewanella) culture was made by aseptically transferring some cells from an eppendorf to the fresh growth medium. 4 micro litre of Shewanella was transferred into 100 ml of LB broth at room temperature. After that, the microorganisms were then incubated at 37 0C with continuous shaking for 24 hours at 150 rpm. After 24 hours, it was observed that the previously transparent LB had changed to a cloudy and opaque solution. That was an indication that the active microorganisms grew in the culture. The culture was subsequently refrigerated. Four H-type MFCs were prepared as was previously done using two similar copies of Duran glass bottles, external metal clips, cation exchange membranes and two rubber gaskets. A membrane was used to divide the two chambers, which were slightly asymmetric, by squeezing the membrane between the two chambers. Two chambers divided by a membrane. The chambers were slightly asymmetric, and the membrane was squeezed between two glass chambers. New graphite plates were used as anode and cathode electrodes, whereas the second and third experiments had used old electrodes, which had to be washed before reusing. The electrodes in this experiment had a different shape from the ones in experiment one. The anode was placed in the centre of the anodic