UCLA

This thesis describes how using a heterotrophy-recovery-autotrophy route (called the green cycle) for the cultivation of Botryococcus braunii results in high biofuel production. Our experiments show that the addition of citrate to a culture can increase cell numbers by up to 20 times compared with the control in the first week. A metal solution was then added to help cells synthesize chlorophyll, enabling Botryococcus braunii to regenerate the chlorophyll content in the plastids and become autotrophic. In our experiments, high cell numbers were obtained after two weeks and biofuel production was enhanced.

We also developed an N-N-A source media which could achieve enhanced cell growth as opposed to using nitrate as the only nitrogen source. This N-N-A source media was able to balance pH variation due to nitrate uptake, so as to maintain the pH level in the media solution without the use of buffer.

By applying these techniques to the Botryococcus braunii culture, we found that cell growth could increase by up to 58 times in comparison with the control