Enhancing 3-hydroxypropionic acid production in Saccharomyces cerevisiae through enzyme localization within mitochondria

Abstract

Microbial 3-hydroxypropionic acid (3-HP) production can potentially replace petroleum-based production methods for acrylic acid. Here, we constructed a yeast strain that expressed enzymes related to 3-HP biosynthesis within the mitochondria. This approach aimed to enhance the 3-HP production by utilizing the mitochondrial acetyl-CoA, an important intermediate for synthesizing 3-HP. The strain that expressed 3-HP-producing enzymes in the mitochondria (YPH-mtA3HP) showed improved production of 3-HP compared to that shown by the strain expressing 3-HP-producing enzymes in the cytosol (YPH-cyA3HP). Additionally, cMCR was overexpressed, which regulates a rate-limiting reaction in synthesizing 3-HP. In this study, we aimed to further enhance 3-HP production by expressing multiple copies of cMCR in the mitochondria using the δ-integration strategy to optimize the expression level of cMCR (YPH-mtA3HPx*). The results of flask-scale cultivation showed that 3-HP production by cMCR δ-integration was significantly higher, exhibiting a yield of 160 mg/L in YPH-mtA3HP6* strain and 257 mg/L in YPH-mtA3HP22* strain. Notably, YPH-mtA3HP22*, exhibited the highest 3-HP titer, which was 3.2-fold higher than that of YPH-cyA3HP. Our results demonstrated the potential of utilizing the mitochondrial compartment within S. cerevisiae for enhancing 3-HP production.