Concomitant Production of Erythritol and β-Carotene by Engineered <i><i>Yarrowia lipolytica</i></i>

Abstract

While the expansion of the erythritol production industry has resulted in unprecedented production of yeast cells, it also suffers from a lack of effective utilization. β-Carotene is a value-added compound that can be synthesized by engineered <i><i>Yarrowia lipolytica</i></i>. Here, we first evaluated the production performance of erythritol-producing yeast strains under two different morphologies and then successfully constructed a chassis with yeast-like morphology by deleting <i>Mhy1</i> and <i>Cla4</i> genes. Subsequently, β-carotene synthesis pathway genes, <i>CarRA</i> and <i>CarB</i> from <i><i>Blakeslea trispora</i>,</i> were introduced to construct the β-carotene and erythritol coproducing <i><i>Y. lipolytica</i></i> strain ylmcc. The rate-limiting genes <i>GGS1</i> and <i>tHMG1</i> were overexpressed to increase the β-carotene yield by 45.32-fold compared with the strain ylmcc. However, increased β-carotene accumulation led to prolonged fermentation time; therefore, transporter engineering through overexpression of <i>YTH1</i> and <i>YTH3</i> genes was used to alleviate fermentation delays. Using batch fermentation in a 3 L bioreactor, this engineered <i><i>Y. lipolytica</i></i> strain produced erythritol with production, yield, and productivity values of 171 g/L, 0.56 g/g glucose, and 2.38 g/(L·h), respectively, with a concomitant β-carotene yield of 47.36 ± 0.06 mg/g DCW. The approach presented here improves the value of erythritol-producing cells and offers a low-cost technique to obtain hydrophobic terpenoids.