Mitochondrial expression of metabolic enzymes for improving carotenoid production in Saccharomyces cerevisiae

Abstract

The utilization of renewable feedstocks for producing bio-based chemicals by Saccharomyces cerevisiae is a viable option. Carotenoids are a class of pigments with important biological functions and are synthesized via the derived mevalonate pathway. Among the various approaches, the accumulation of intermediates is an important strategy to enhance carotenoid production in yeast. Acetyl-CoA is an important intermediate synthesized mainly in the cytosol and mitochondria. Here, we focused on the utilization of accumulated intermediates, including acetyl-CoA, in mitochondria by compartmentalization of enzymes. Hence, we attempted localizing enzymes related to carotenoid production in the mitochondria to improve carotenoid production in S. cerevisiae. The strain that expressed carotenoid-producing enzymes in the mitochondria (YPH-mtβ) showed improved production of carotenoid compared to that shown by the strain expressing carotenoid-producing enzymes in the cytosol (YPH-cyβ). In addition, the increase in glucose concentration resulted in improved cell growth and carotenoid production in YPH-mtβ, but not in YPH-cyβ (0.354 or 0.023 mg/L culture/OD600 with 120 g/L glucose after 48 h of cultivation with YPH-mtβ or YPH-cyβ, respectively). These results show that the mitochondrial compartmentalization of enzymes can provide a new strategy for the improvement of carotenoid production by S. cerevisiae.