Systematic modulating carbon metabolism to improve α-farnesene production in Pichia pastoris

Abstract

α-farnesene, a simple acyclic sesquiterpenes, has significant economic value in medicine, condiments, cosmetics and bioenergy. In this study, we increased α-farnesene production through modifying three module pathways: the main MVA biosynthesis module, the farnesyl pyrophosphate (FPP) branch module and the cytosolic acetyl-CoA supply module. To do these, the appropriate promoters were used to control the expression level of the key enzymes to strengthen the main MVA biosynthesis module and the cytosolic acetyl-CoA supply module as well as to weaken FPP branch module in P. pastoris X33 with expression of α-farnesene synthase (αFS) from Malus domestica. As a result, a α-farnesene high-producing strain P. pastoris XF22 was obtained, which produced 17.92 ± 1.35 g/L of α-farnesene with a productivity of 0.107 g/(L·h) and a yield of 0.078 g/(g glucose) after 168 h in fed-batch fermentation. Although the titer of α-farnesene is not the highest, the productivity and the yield in this study are the highest among the reported literatures, demonstrating that strain XF22 is a competitive platform strain for α-farnesene production.