The biotechnology of microalgae has attracted considerable interest in recent decades owing to it is potential to provide renewable energy and its capacity to produce bioactive molecules such as carotenoids, fatty acids and other high value compounds, which can be used in the biomaterials, cosmetics and pharmaceuticals industries. One microalga of particular interest is Nannochloropsis gaditana, which is a robust marine unicellular species that naturally produces large quantities of storage lipids. The availability of a recently completed draft genomic sequence, a protocol for nuclear genome transformation and its high lipid productivity have positioned N. gaditana as a promising oleaginous alga for metabolic engineering. However, to develop N. gaditana as an industrially relevant algal platform, a set of molecular tools is needed to facilitate gene functional analysis and genetic engineering of metabolic pathways, particularly those located in the chloroplast. Thus, the aim of this project is to develop a reliable chloroplast transformation method for the alga. The research has therefore involved optimizing the cultivation conditions for N. gaditana, the evaluation of sensitivity to antibiotic and herbicide compounds in order to identify suitable selectable markers, and the creation of transformation vectors for introduction of novel genes into the chloroplast genome. An initial plasmid carrying a bacterial chloramphenicol resistance marker failed to generate transformants despite testing two DNA delivery methods – biolistics and electroporation. A forward-genetics approach is therefore being used to develop an endogenous marker based on a variant of the chloroplast psbA gene that confers resistance to the herbicide, atrazine. Following development of transformation methodology, the focus will be metabolic engineering of the chloroplast to produce high value terpene products.

The biotechnology of microalgae has attracted considerable interest in recent decades owing to it is potential to provide renewable energy and its capacity to produce bioactive molecules such as carotenoids, fatty acids and other high value compounds, which can be used in the biomaterials, cosm...