Bacteria in Biofuel Production

In this work, bacteria are regarded either as production organisms or as interacting organisms with another production organism, namely yeast. The aim of using bacteria as a production organism was, to optimize Rubisco activity by introducing additional gene cassettes of Rubisco in Cyanobacteria. At first, RBC operon was tried to clone in pDF-Trc plasmid, using infusion cloning, but did not obtained E. coli transformants containing the RBC operon, when E.coli was transformed with infusion cloning reaction. This might be because of the plasmid concentration that was used, which was less than the recommended concentration. When cloning the RBC operon by conventional restriction/ligation, E. coli transformants containing the operon were obtained. Further characterisation of the cloned operon could not be performed during this project. In the second part of the project, the ethanol tolerant lactic acid bacterium Lactobacillus vini was investigated, with a special focus on its interaction with ethanol producing organisms, Saccharomyces cerevisiae and Dekkera bruxellensis. Lower ethanol concentrations did not have any considerable effect on the growth of L. vini. However, at higher ethanol concentration, a continuous decrease in cell numbers of L. vini was observed. The study shows, that L. vini can tolerate and survive higher ethanol concentrations, as compared to other microorganisms. L. vini had better growth rate, when it was co-cultured separately with Saccharomyces cerevisiae and Dekkera bruxellensis compared to, when it was co-cultured with both the yeasts. Ethanol production in batch was relatively higher when L. vini was cocultured with S. cerevisiae compared to co-cultivation with D. bruxellensis and with both yeasts, which is most probably due to the rapid growth of S. cerevisiae compared to D. bruxellensis