Genetically engineered herbicide resistance for maintaining axenic cultures

This disclosure provides herbicide resistant algae and cyanobacteria. This disclosure also provides a method to cultivate algae and cyanobacteria in axenic cultures without contaminating species. Moreover, this disclosure provides transgenic algal and cyanobacterial cells that are capable of high production in high light intensities as typically applied in cultivation. Furthermore, a novel transformation method is provided for algal cells.