Improvement of lipid content in green algae for subsequent use in bio-fuel production

Full text: Heterotrophic cultivation technique of microalgae, Tetraselmis suecica, in shake flask under different medium composition and culture conditions were developed aimed at improvement of the cell composition and biomass production for subsequent used in bio diesel synthesis. Heterotrophic microalgae cell was developed from the adaptation of the photo trophic cell by photo periodic, manipulation of medium and culture conditions. The performance of heterotrophic cultivation of T. suecica was substantially improved in term of growth rate, final cell concentration, specific growth rate and productivity as well as cell composition especially totals lipid concentration. The cultivation time to reach maximum cell concentration was decreased from 408 hr in photoautotrophic to 142 hr in heterotrophic cultivation. The final cell concentration (24.3 g/L) was increased more than three times in heterotrophic cultivation as compared to that obtained in photoautotrophic cultivation (8.4 g/L). In addition, the maximum productivity (0.17 g/L.h-1) for heterotrophic cultivation was nine times higher than photoautotrophic cultivation (0.02 g/L.h-1). Moreover the among of protein decreased from 47.7 percentage of dry cell weight in photoautotrophic to 10.5 percent in heterotrophic cells. On the other side the total lipid (53.8) and carbohydrate (14.8) percentage of dry cell weight in heterotrophic cells increased more than two times compare with photoautotrophic cells (24.5 and 7.4 respectively) that is very important from bio fuel production viewpoint. (author)