Dataset Information

Downregulation of ammonium uptake improves the growth and tolerance of Kluyveromyces marxianus at high temperature.

ABSTRACT: The growth and tolerance of Kluyveromyces marxianus at high temperatures decreased significantly in the synthetic medium (SM), which is commonly used in industrial fermentations. After 100 days of adaptive laboratory evolution, a strain named KM234 exhibited excellent tolerance at a high temperature, without loss of its growth ability at a moderate temperature. Transcriptomic analysis revealed that the KM234 strain decreased the expression of the ammonium (NH₄ ⁺ ) transporter gene MEP3 and increased the synthesis of the amino acid carbon backbone, which may contribute greatly to the high-temperature growth phenotype. High NH₄ ⁺ content in SM significantly increased the reactive oxygen species (ROS) production at high temperatures and thus caused toxicity to yeast cells. Replacing NH₄ ⁺ with organic nitrogen sources or increasing the concentration of potassium ions (K⁺ ) in the medium restored the growth of the wild-type K. marxianus at a high temperature in SM. We also showed that the NH₄ ⁺ toxicity mitigated by K⁺ might closely depend on the KIN1 gene. Our results provide a practical solution to industrial fermentation under high-temperature conditions.

SUBMITTER: Ai Y

PROVIDER: S-EPMC9131600 | biostudies-literature | 2022 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Downregulation of ammonium uptake improves the growth and tolerance of Kluyveromyces marxianus at high temperature.

Ai Yi Y Luo Tongyu T Yu Yao Y Zhou Jungang J Lu Hong H

MicrobiologyOpen 20220601 3

The growth and tolerance of Kluyveromyces marxianus at high temperatures decreased significantly in the synthetic medium (SM), which is commonly used in industrial fermentations. After 100 days of adaptive laboratory evolution, a strain named KM234 exhibited excellent tolerance at a high temperature, without loss of its growth ability at a moderate temperature. Transcriptomic analysis revealed that the KM234 strain decreased the expression of the ammonium (NH<sub>4</sub><sup>+</sup> ) transporte ...[more]

PMID: 35765191

Similar Datasets

Project description:BackgroundCurrently, the synthesis of compounds based on microbial cell factories is rapidly advancing, yet it encounters several challenges. During the production process, engineered strains frequently encounter disturbances in the cultivation environment or the impact of their metabolites, such as high temperature, acid-base imbalances, hypertonicity, organic solvents, toxic byproducts, and mechanical damage. These stress factors can constrain the efficiency of microbial fermentation, resulting in slow cell growth, decreased production, significantly increased energy consumption, and other issues that severely limit the application of microbial cell factories.ResultsThis study demonstrated that sterol engineering in Kluyveromyces marxianus, achieved by overexpressing or deleting the coding genes for the last five steps of ergosterol synthase (Erg2-Erg6), altered the composition and ratio of sterols in its cell membrane, and affected its multiple tolerance. The results suggest that the knockout of the Erg5 can enhance the thermotolerance of K. marxianus, while the overexpression of the Erg4 can improve its acid tolerance. Additionally, engineering strain overexpressed Erg6 improved its tolerance to elevated temperature, hypertonic, and acid. YZB453, obtained by overexpressing Erg6 in an engineering strain with high efficiency in synthesizing xylitol, produced 101.22 g/L xylitol at 45oC and 75.11 g/L xylitol at 46oC. Using corncob hydrolysate for simultaneous saccharification and fermentation (SSF) at 46oC that xylose released from corncob hydrolysate by saccharification with hemicellulase, YZB453 can produce 45.98 g/L of xylitol, saving 53.72% of the cost of hemicellulase compared to 42oC.ConclusionsThis study elucidates the mechanism by which K. marxianus acquires resistance to various antifungal drugs, high temperatures, high osmolarity, acidity, and other stressors, through alterations in the composition and ratio of membrane sterols. By employing sterol engineering, the fermentation temperature of this unconventional thermotolerant K. marxianus was further elevated, ultimately providing an efficient platform for synthesizing high-value-added xylitol from biomass via the SSF process at temperatures exceeding 45 °C.

Dataset Information

Downregulation of ammonium uptake improves the growth and tolerance of Kluyveromyces marxianus at high temperature.

Publications

Downregulation of ammonium uptake improves the growth and tolerance of Kluyveromyces marxianus at high temperature.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets