Open AccessDownregulation of ammonium uptake improves the growth and tolerance of Kluyveromyces marxianus at high temperature
Author(s) -
Ai Yi,
Luo Tongyu,
Yu Yao,
Zhou Jungang,
Lu Hong
Publication year - 2022
Publication title -
microbiologyopen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.881
H-Index - 36
ISSN - 2045-8827
DOI - 10.1002/mbo3.1290
Subject(s) - kluyveromyces marxianus , ammonium , yeast , strain (injury) , chemistry , fermentation , carbon fibers , toxicity , biochemistry , biology , saccharomyces cerevisiae , organic chemistry , materials science , anatomy , composite number , composite material
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 4 + ) transporter gene MEP3 and increased the synthesis of the amino acid carbon backbone, which may contribute greatly to the high‐temperature growth phenotype. High NH 4 + content in SM significantly increased the reactive oxygen species (ROS) production at high temperatures and thus caused toxicity to yeast cells. Replacing NH 4 + 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 NH 4 + toxicity mitigated by K + might closely depend on the KIN1 gene. Our results provide a practical solution to industrial fermentation under high‐temperature conditions.