Engineering Yarrowia lipolytica for efficient γ-linolenic acid production

Abstract

γ-Linolenic acid (GLA) has various well-documented beneficial physiological effects and high biological significance. Because the natural supply of GLA is insufficient, microbial GLA production is a promising method for pharmaceutical and nutraceutical purposes. To establish and develop a biotechnological process for GLA production by Yarrowia lipolytica, the codon-optimized △6-desaturase from Mortierella alpina was introduced into this yeast under the control of the strong hp4d promoter. A recombinant Y. lipolytica strain was constructed, which produced 4.6% GLA in total fatty acids. By using a temperature-shift strategy of cultivation, consisting in preliminary growth at 28°C followed by 6-day culture at 20°C, optimal levels of dry cell weight (DCW), lipid content and GLA concentration were obtained from the recombinant strain: 18.55g/L, 1.16g/L and 71.6mg/L, respectively. These DCW, lipid and GLA values were respectively 25.7%, 19.6% and 60.9% higher than those obtained in the control cultivation experiment at the standard constant temperature of 28°C. This work demonstrates the excellent capacity of Y. lipolytica for GLA production, by combining metabolic engineering with a temperature-shift strategy.