Zeaxanthin production by metabolic engineering approach

Zeaxanthin is a carotenoid molecule which, with time, gained particular importance in pharmaceutical industries, as well as in food industries as food supplement, colorant and animal food additive. The aim of this thesis was to make heterologous expression of zeaxanthin in Escherichia coli by using metabolic engineering principles. In order to ensure the heterologous zeaxanthin production in E. coli, the plasmid (pAC-EHER-EBIidiYZ) carrying the genes (crtEBIYZ) which are responsible for expression of enzymes involved in zeaxanthin biosynthesis, was assembled using the Gibson Assembly Method. This newly constructed plasmid was transformed into different E. coli strains (E. coli MG1655, E. coli NEB 10-beta, E. coli DH5α, E. coli DH5α-Pro, E. coli NEB-Turbo, E. coli XL1-Blue, E. coli TOP10, E. coli EPI300, E. coli DE3) and their liquid cultures were prepared. From bacterial cultures which were prepared in the above manner, time-related zeaxanthin production was measured by zeaxanthin extraction and analyzing the extraction products with the HPLC (High Pressure Liquid Chromotography). In this study, zeaxanthin analyses was done by HPLC in E. coli strains which were transformed with pAC-EHER-EBIidiYZ plasmid during 72 hours incubation and at the 24th hour the highest zeaxanthin production was found as 2,786±0,145 mg/l for E. coli MG1655 strain, 2,757±0,102 mg/l for E. coli NEB 10-beta strain, 2,669±0,104 mg/l for E. coli DH5α strain. Key words: Zeaxanthin, Escherichia coli, Heterolog Production, Metabolic Engineering