The heterologous synthesis of lycopene in non-carotenogenic Escherichia coli required the introduction of the biosynthesis genes crtE, crtB, and crtI. Recombinant E. coli strains, expressing each lycopene biosynthesis gene from Pantoea ananatis using multi-copy plasmid or single-copies after stable chromosomal integration, were cultivated and the formation of lycopene was investigated. The different expression conditions significantly influenced the lycopene formation as well as the growth behaviour. High plasmid expression levels of crtI with a single copy background of crtE and crtB in E. coli led to a predominate synthesis of tetradehydrolycopene at 253 mu g g(-1) (cdw).