Carotenoid production in selected haploid deletion strains. The selected haploid deletion strains were transformed with YEplac195-YB/I/E plasmid. Cells were grown in 50 ml glucose CM-uracil for 5 days. Carotenoids were extracted from liquid cultures and quantified. In green, dos2, the highest producing deletion and rox1, a previously identified enhancer of carotenoid biosynthesis. The wild type BY4741 parental is shown in blue color.