In an attempt to accumulate lycopene in the bacterium Dietzia natronolimnaea HS-1 cultured in beet molasses, the influence of lycopene cyclase inhibitors on carotenogenesis (within the range 0-60 ppm) were evaluated. All inhibitors blocked the biosynthesis of canthaxanthin and resulted in accumulation of lycopene as the predominant carotenoid. As the final step of a study aiming at the optimization of culture conditions, a central composite design to a fed-batch process was applied to optimize the concentrations of lycopene cyclase inhibitors (within the range 0-50 ppm) in order to achieve high level accumulation of lycopene from D. natronolimnaea HS-1 cultured in beet molasses. On the basis of this approach, the optimum concentrations of lycopene cyclase inhibitors required to achieve the highest level of lycopene accumulation ($8.26pm0.17$ mg/L) were determined as follows: imidazole, 24.74 ppm; nicotinic acid, 28 ppm; piperidine, 24.05 ppm; pyridine, 27.6 ppm; and triethylamine, 23.22 ppm.