Characterizing an engineered carotenoid-producing yeast as an anti-stress chassis for building cell factories

Abstract

Background A microorganism engineered for non-native tasks may suffer stresses it never met before. Therefore, we examined whether a Kluyveromyces marxianus strain engineered with a carotenoid biosynthesis pathway can serve as an anti-stress chassis for building cell factories. Results Carotenoids, a family of antioxidants, are valuable natural products with high commercial potential. We showed that the free radical removal ability of carotenoids can confer the engineered host with a higher tolerance to ethanol, so that it can produce more bio-ethanol than the wild type. Moreover, we found that this engineered strain has improved tolerance to other toxic effects including furfurals, heavy metals such as arsenate (biomass contaminant) and isobutanol (end product). Furthermore, the enhanced ethanol tolerance of the host can be applied to bioconversion of a natural medicine that needs to use ethanol as the delivery solvent of hydrophobic precursors. The result suggested that the engineered yeast showed enhanced tolerance to ethanol-dissolved hydrophobic 10-deacetylbaccatin III, which is considered a sustainable precursor for paclitaxel (taxol) bioconversion. Conclusions The stress tolerances of the engineered yeast strain showed tolerance to several toxins, so it may serve as a chassis for cell factories to produce target products, and the co-production of carotenoids may make the biorefinary more cost-effective.

Adaptation of Proteome and Metabolism in Different Haplotypes of Rhodosporidium toruloides during Cu(I) and Cu(II) Stress

“…Generally, cellular detoxification of these ROS compounds is mediated by specialized oxidoreductases, including peroxidases, catalases, and superoxidases [ 11 , 12 ]. Additionally, carotenoids are known to exhibit antioxidant activities, acting as radical quenchers that are able to inactivate different ROS [ 12 , 13 ]. Furthermore, both the cell wall and cell membrane act as barriers to protect the cell from the environment and undergo modification when exposed to stress [ 14 ].…”

Tryptophan plays an important role in yeast’s tolerance to isobutanol

“…However, as the production of a novel compound creates a stress to the host, it becomes a hurdle in mass production [ 6 ]. To solve this problem, genetic modifications have been made to obtain tolerant strains [ 7 , 8 ]. Our previous study has provided an example for increasing ethanol and n -butanol productivity through enhanced tolerance of the host cell by removing oxidative stress in E. coli [ 9 ].…”

MAL62 overexpression enhances uridine diphosphoglucose-dependent trehalose synthesis and glycerol metabolism for cryoprotection of baker’s yeast in lean dough

“…However, freezing often causes oxidative stress and cell death to baker’s yeast [ 3 ], which reduces the yeast growth and gas production capacity [ 4 , 5 ]. A number of protective molecules have been identified in yeast stress tolerance [ 6 – 8 ]. Among them, the disaccharide trehalose, which protects the cell membrane and stabilizes the protein structure, has captured wide attention [ 9 ].…”