Enhancing β-farnesene production in engineered Yarrowia lipolytica: A new process control strategy

beta-Farnesene, a sesquiterpene with diverse applications, is applied in fields ranging from bioenergy and agriculture to medicine. In this study, a series of fermentation conditions and process control strategies were employed to enhance the accumulation of beta-farnesene. Through the optimization of medium components, a suitable environment was created for beta-farnesene biosynthesis in Yarrowia lipolytica, using only three inorganic salts as the initial medium. On this basis, cell growth and citrate supply were enhanced by adjusting the feeding time point, which begins when dissolved oxygen level below 40%. Additionally, initial cell density and glucose concentration during fermentation were separately optimized. Ultimately, nitrogen -limited conditions were applied to maximize carbon flux towards beta-farnesene synthesis and the ideal condition was found to be C/N ratio of 100. Under the optimal condition, the titer of beta-farnesene was increased by 227%, reaching 22.04 g/L in a 2 L bioreactor. This study optimizes terpenoid biosynthesis fermentation control and establishes a platform for the potential utilizing of waste biomass in Y. lipolytica.