Electronic Thesis and Dissertation Repository


Master of Engineering Science


Chemical and Biochemical Engineering


Dr. Lars Rehmann


Limited fossil fuel reserves, increasing demand for energy in all parts of the world are some driving forces to look for new sources of transportation fuels. Among different options available, microalgae are currently attracting wide interests as an alternative and renewable fuel source.

Microalgae are single cell photosynthetic organisms that are known for rapid growth and high energy content and as a part of photosynthesis; they produce oil that can be used as a feedstock for biodiesel production. Some algae strains could contain lipid up to 80% of the dry biomass. The amount of lipid production is in direct relation with the medium composition and growth conditions of algae.

For biodiesel production from microalgae, increasing the growth rate and lipid content are the main goals. It has been suggested by some researchers that there are plant hormones capable of improving growth rate and biomass. Plant hormones are chemicals produced by plants and play a crucial role in controlling the way in which plants grow and develop.

In this research, the effect of different plant hormones from Brassinosteroids (BRs), Auxin and cytokinin families on biomass, growth kinetic and lipid content of chlorella vulgaris was investigated, and it was found that of the tested hormones only Epibrassinolide has a positive effect on the growth of microalgae. At initial concentrations between 10-12M and 10-10M the total amount of biomass produced was doubled. The lipid content of the algae remained unchanged, resulting in an overall increase of lipid production.

Additionally an ionic liquid mediated process for the extraction of lipids was investigated and a one-pot process combining lipid extraction and trans-esterification was proposed.